Transparent Labs Lean Pre-Workout Review
Transparent Labs Lean Pre-Workout is a powdered pre-workout supplement. The label lists a serving size of 1 scoop (13.7g), and each container holds 30 servings. Each serving has 5 calories. The main ingredients per serving, as printed on the label, are Citrulline Malate 2:1 at 6000 mg, Beta-Alanine at 2000 mg, Betaine Anhydrous at 1500 mg, Acetyl L-Carnitine HCl at 1000 mg, Choline Bitartrate at 500 mg, L-Theanine at 180 mg, PurCaf Organic Caffeine at 180 mg, Theobromine at 50 mg, Bioperine at 5 mg, and Huperzine A at 100 mcg. The label also lists minerals: iodine 225 mcg, zinc 15 mg, selenium 55 mcg, copper 1 mg, and chromium 200 mcg. Other ingredients are Natural Flavors (900mg), Stevia Extract (350mg), Calcium Silicate (305mg), Silicon Dioxide (305mg), and Rebaudioside M from stevia extract (105mg). No directions for use are printed in the label information provided, so check the container for them.
Tier ⓘ
Tier 4 · Rank 3
Tier 4 · Emerging. A promising mechanism or animal data, with thin human evidence so far. Rank 3 within Tier 4 for Thyroid Health; 32 of 61 overall. Tiers run from 1, the strongest evidence, to 5. How we grade →
Evidence ⓘ
57 /100
How strongly the evidence says this product works: human studies count most, then real reviews, then our biohacker panel.
Positive Reviews
84% of 334
Biohacker Mentions
9 of 10
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Study, Trial or Testing Result Summary
Members Only168 human studies · 48 improved
2 of these 168 human studies gave the ingredient by drip or injection, not by mouth.
168 human studies48 improved76 no effect643,349 people studied
This is a pre-workout. Its main ingredients, citrulline malate, beta-alanine, betaine, acetyl carnitine, theanine, theobromine and huperzine A, have no human studies for thyroid health. Caffeine showed no thyroid benefit [1][2], and choline has no study showing it helps the thyroid [3]. Any thyroid support comes from the added minerals. Iodine at a full dose helps mainly people who lack it, shrinking goitre [4] and cutting cretinism in iodine-poor pregnancies [5], though too much can slow thyroid recovery [6]. Selenium reaches the studied dose at two servings. It lowered thyroid antibodies in Hashimoto thyroiditis [7] and restored normal function in some people with a mildly underactive thyroid [8], but one review judged the evidence too weak to recommend it [9]. Zinc, at a full dose with two servings, raised active thyroid hormone only with low certainty. The clearest benefit came when it was combined with magnesium and vitamin A, which this product does not contain [10]. Other zinc trials found little or no change [11][12]. Copper showed no clear benefit [13]. Chromium cut absorption of thyroid hormone medicine [14]. Animal and cell studies are never counted.
See all 168 studies →Hide the studies
- A pooled analysis of 114 observational studies found lower zinc in thyroid cancer tissue, but it did not test zinc supplements and is about cancer rather than thyroid health.Serum and tissue zinc in epithelial malignancies: a meta-analysis.
- In a pooled analysis of 35 trials with 3,508 people with underactive thyroid, adding zinc to a med raised free triiodothyronine (low certainty), and zinc with magnesium and vitamin A raised free thyroxine (high certainty).Additional treatment strategies for hypothyroidism: a network meta-analysis.
- Pooling randomized trials in people with Hashimoto thyroiditis, selenium lowered thyroid-stimulating hormone (in those not on thyroid hormone replacement), thyroid antibodies and an oxidative stress marker, with no more side effects than control.Selenium Supplementation in Patients with Hashimoto Thyroiditis: A Systematic Review and Meta-Analysis of Randomized Cli…
- In 10 case-control studies with 2205 people, those with thyroid cancer had lower blood selenium than healthy people, but this does not test whether taking selenium helps.Relationship between Serum Levels of Selenium and Thyroid Cancer: A Systematic Review and Meta-Analysis.
- Across 21 randomized trials in 1610 people with Hashimoto thyroiditis, selenium lowered thyroid antibodies at 3 and 6 months and thyroid-stimulating hormone at 6 months, with selenomethionine working better than sodium selenite or selenium yeast.Clinical efficacy of selenium supplementation in patients with Hashimoto thyroiditis: A systematic review and meta-analy…
- Across eight studies of 1291 people, those with thyroid cancer had higher blood copper levels than healthy people, but no copper was given, so this shows an association only.The Association Between Serum Levels of Selenium, Copper, and Magnesium with Thyroid Cancer: a Meta-analysis.
- In 11 studies of children given radioactive treatment for neuroblastoma, about 41% still had raised thyroid-stimulating hormone despite iodine blockade, which worked better when given longer and combined with other drugs than potassium iodide alone.Incidence of subclinical and overt hypothyroidism in children treated with [131I]mIBG: a systematic review and meta-anal…
- In 31 mostly cross-sectional studies, low iodine intake raised the odds of thyroid nodules by about 24%, while higher or excessive intake showed no consistent effect.The myth of iodine: A systematic review and meta-analysis on the relationship between iodine and thyroid nodule.
- A pooled analysis of 32 observational studies found people with underactive thyroid had lower blood zinc than healthy people, but it did not test zinc supplements.Trace Element Status and Hypothyroidism: A Systematic Review and Meta-analysis.
- A pooled analysis of 10 observational studies found blood zinc was not significantly lower in people with thyroid cancer than in healthy controls.Zinc Status and Occurrence of Thyroid Cancer: Systematic Review and Meta-Analysis.
- In 23 trials in adults with autoimmune thyroiditis, selenium lowered thyroid antibodies and thyroid echogenicity but did not change thyroid-stimulating hormone and carried a higher risk of side effects, so the authors judged the evidence insufficient to justify its use.Insufficient evidence to support the clinical efficacy of selenium supplementation for patients with chronic autoimmune …
- In four randomized trials of people with Graves' orbitopathy (thyroid eye disease), selenium beat placebo at 6 and 12 months for eye disease activity and quality of life, with no difference in adverse effects.The efficacy and safety of selenium supplementation versus placebo in the treatment of Graves' orbitopathy: A systematic…
- In a pooled analysis of 10 trials in people with Hashimoto's thyroiditis and normal thyroid function, selenium lowered thyroid antibody levels more than placebo, over treatment of about 6 months.Effects of different supplements on Hashimoto's thyroiditis: a systematic review and network meta-analysis.
- A summary of 8 reviews of scans using radiolabelled tracers, including choline, found unexpected thyroid spots are not rare and carry a real cancer risk, but it did not test choline as a supplement for thyroid health.Evidence-Based Data About Prevalence and Risk of Malignancy of Thyroid Incidentalomas Detected by Different PET Radiopha…
- Across three trials of 1551 pregnant women in iodine-deficient areas, iodine supplements cut childhood cretinism by about 73% and infant deaths by about 29%, with no apparent harm.Maternal iodine supplements in areas of deficiency.
- This withdrawn review of three trials in 1551 pregnant women found iodine supplements reduced childhood cretinism and infant deaths with no apparent harm.WITHDRAWN: Maternal iodine supplements in areas of deficiency.
- In four trials with 463 people with Hashimoto thyroiditis (average 7.5 months), 200 mcg selenomethionine lowered thyroid antibodies versus placebo in several trials, but the trials were at unclear to high risk of bias so evidence was judged incomplete.Selenium supplementation for Hashimoto's thyroiditis.
- A review of 25 patients with cobalt poisoning from chrome-cobalt hip implants found thyroid symptoms in 48%, but this was driven by blood cobalt rather than blood chromium, and no chromium supplement was given.A Systematic Review of Systemic Cobaltism After Wear or Corrosion of Chrome-Cobalt Hip Implants.
- Across 27 randomized trials of iodine used on wounds, thyroid problems were not more frequent with iodine than with other treatments.Benefit and harm of iodine in wound care: a systematic review.
- A review of iodine status in Eastern Mediterranean countries found iodine deficiency is controlled in some countries with salt iodization but remains a serious problem in others.Iodine deficiency status in the WHO Eastern Mediterranean Region: a systematic review.
- A review of 11 studies found results on zinc and other supplements and thyroid cancer risk were inconsistent and inconclusive.Vitamin and mineral supplements and thyroid cancer: a systematic review.
- A review of 57 studies found observational links between zinc and iodine status, but randomized trials did not confirm this relationship.Micronutrients, iodine status and concentrations of thyroid hormones: a systematic review.
- A review of eight zinc supplementation studies and ten blood zinc studies found the evidence on whether zinc changes thyroid hormone levels inconclusive because results differed and came only from people with illness.Relation Between Zinc and Thyroid Hormones in Humans: a Systematic Review.
- A review of 13 trials in people with overweight or obesity found zinc raised free triiodothyronine, but this rested on one study in people with underactive thyroid and the overall effect on thyroid function could not be determined.The Effects of Zinc and Selenium Supplementation on Body Composition and Thyroid Function in Individuals with Overweight…
- A review of studies on trace elements and thyroid disease found few supplementation trials, but zinc supplementation lowered a marker of oxidative damage (malondialdehyde) in people with underactive thyroid.The Role of Selected Trace Elements in Oxidoreductive Homeostasis in Patients with Thyroid Diseases.
- In five cross-sectional studies, some found lower selenium in people with thyroid cancer and others found no difference, so the evidence is inconclusive and no selenium was given.Selenium and thyroid cancer: a systematic review.
- An overview of 6 systematic reviews covering 75 trials found selenium may lower thyroid antibodies at 3 and 6 months in autoimmune thyroiditis, but the certainty of evidence was low to very low.The Effects of Selenium Supplementation in the Treatment of Autoimmune Thyroiditis: An Overview of Systematic Reviews.
- In severely burned patients, intravenous trace element supplements including up to 4 mg of copper a day for 3 weeks were reported to be safe, improve recovery and normalize thyroid function, but copper was given with selenium and zinc and the abstract gives no patient numbers.Trace element requirements in critically ill burned patients.
- A review of 23 studies on electronic waste exposure found thyroid function changes that were not consistent across studies, and it did not test chromium as a supplement for thyroid health.Health consequences of exposure to e-waste: a systematic review.
- A review of 15 articles on scans using radiolabelled choline (a diagnostic tracer, not a supplement) found thyroid spots showed up unexpectedly and were cancerous in about half of case reports, so it says nothing about choline improving thyroid health.F18-choline/C11-choline PET/CT thyroid incidentalomas.
- In pregnant women with thyroid antibodies, 200 mcg of selenomethionine daily during pregnancy and after birth reduced the rate of postpartum thyroid dysfunction (28.6% vs 48.6% with placebo) and permanent hypothyroidism.The influence of selenium supplementation on postpartum thyroid status in pregnant women with thyroid peroxidase autoant…
- In 491 older Danes followed for five years, selenium yeast at 100 to 300 mcg daily slightly lowered TSH and free T4 versus placebo, with no effect on free T3, and the authors do not recommend it for marginal deficiency.Does selenium supplementation affect thyroid function? Results from a randomized, controlled, double-blinded trial in a …
- In 430 people with newly diagnosed Graves' hyperthyroidism, 200 mcg of selenium daily for 24 to 30 months alongside standard drugs did not increase remission or improve quality of life compared with placebo.Selenium supplementation in individuals with newly diagnosed Graves' hyperthyroidism: a double-blind, multi-centre RCT.
- In 368 healthy older UK adults, taking high-selenium yeast for 6 months raised blood selenium but did not change thyroid hormone levels compared with placebo.Randomized controlled trial of the effect of selenium supplementation on thyroid function in the elderly in the United K…
- In 324 Tibetan children with Kashin-Beck disease, selenium supplementation for 12 months did not change joint symptoms, growth or thyroid function compared with placebo once iodine deficiency was corrected.Selenium and iodine supplementation of rural Tibetan children affected by Kashin-Beck osteoarthropathy.
- In 307 thyroid cancer patients given radioactive iodine, those prepared with recombinant thyrotropin had success rates of 43.8% versus 47.1% with hormone withdrawal, meeting the noninferiority standard with fewer side effects.Recombinant Human Thyrotropin Plus Radioactive Iodine Among Patients With Thyroid Cancer: A Noninferiority Randomized Cl…
- In 230 pregnant women in the UK with mild iodine deficiency, 60 mcg of selenium daily until delivery did not lower thyroid antibodies more than placebo, though it tended to change thyroid function in women who had thyroid antibodies.Effect of low-dose selenium on thyroid autoimmunity and thyroid function in UK pregnant women with mild-to-moderate iodi…
- In 196 people with autoimmune thyroiditis and mild underactive thyroid, 83 mcg of selenomethionine daily for four months restored normal thyroid function in 31% of those taking it, compared with 3% of controls.Selenium supplementation could restore euthyroidism in subclinical hypothyroid patients with autoimmune thyroiditis.
- In 170 women with Hashimoto's thyroiditis, a 6-month course of selenomethionine reduced immune cell release of inflammatory cytokines and lowered C-reactive protein compared with placebo, with the strongest effect when combined with a med.Read the study on PubMed (21508145) →
- In 168 people with Hashimoto's thyroiditis and mildly raised thyroid-stimulating hormone, adding myo-inositol to selenium for six months lowered thyroid-stimulating hormone and thyroid antibodies and raised free thyroxine more than selenium alone.Myo-inositol plus selenium supplementation restores euthyroid state in Hashimoto's patients with subclinical hypothyroid…
- In 166 people with iodine-deficiency goitre, 400 mcg iodine daily for 8 months shrank the thyroid by about 37%, similar to a med, and the shrinkage was sustained 4 months after stopping (-32.5%).Read the study on PubMed (2515973) →
- In 147 people with Graves' disease given radioactive iodine, 94% of those dosed by the target thyroid mass method were cured at one year, similar to 97% with a fixed high dose that needed more radioactivity.Personalization of radioiodine treatment for Graves' disease: a prospective, randomized study with a novel method for ca…
- In 134 adults with autoimmune thyroiditis, 200 mcg of selenium yeast daily for 6 months lowered thyroid antibody levels, and antibodies fell in 52 of the 77 people who took it.[Effects of selenium supplementation on antibodies of autoimmune thyroiditis].
- In 102 adults with autoimmune thyroiditis, 200 mcg of selenium daily for 3 months lowered thyroid antibodies within the group, but the change was no greater than placebo or vitamin C.Effects of selenium and vitamin C on the serum level of antithyroid peroxidase antibody in patients with autoimmune thyr…
- In 100 older New Zealanders aged 60 to 80, 100 mcg of selenium daily for 3 months raised selenium and antioxidant enzyme levels but did not change thyroid hormone levels compared with placebo.Selenium and iodine supplementation: effect on thyroid function of older New Zealanders.
- In 90 people with Hashimoto's thyroiditis, 6 months of selenious yeast tablets lowered thyroid antibodies and TSH compared with no treatment; the dose was not stated in the abstract.Effect of selenium on thyroid autoimmunity and regulatory T cells in patients with Hashimoto's thyroiditis: A prospectiv…
- In 88 women with autoimmune thyroiditis, 200 micrograms of selenium daily for 3 months cut thyroid antibody levels by about 26 percent, while placebo caused no change; lower doses of 100 micrograms gave weaker results.Selenium treatment in autoimmune thyroiditis: 9-month follow-up with variable doses.
- In 86 adults with underactive thyroid, 10 weeks of zinc combined with magnesium and vitamin A raised free thyroxine and lowered an inflammation marker (hs-CRP), while thyroid-stimulating hormone did not change significantly.Randomized Study of the Effects of Zinc, Vitamin A, and Magnesium Co-supplementation on Thyroid Function, Oxidative Stre…
- In 77 adults with high cholesterol taking Brazil nut flour providing about 227 mcg of selenium daily for 90 days, total cholesterol fell, but this was not different from the placebo group, and thyroid health was not measured as an improvement.Intake of partially defatted Brazil nut flour reduces serum cholesterol in hypercholesterolemic patients--a randomized c…
- In 71 children and adolescents with autoimmune thyroiditis, 200 mcg of selenium daily for 6 months lowered one thyroid antibody more than placebo, but the other antibody did not differ significantly.l-selenomethionine supplementation in children and adolescents with autoimmune thyroiditis: A randomized double-blind pl…
- In 70 adults with autoimmune thyroiditis, 200 mcg of selenium daily for 3 months lowered thyroid antibody levels compared with placebo, while thyroid hormone levels did not change.Selenium supplementation in patients with autoimmune thyroiditis decreases thyroid peroxidase antibodies concentrations.
- In 70 people with untreated Graves' hyperthyroidism, 300 mcg of selenite daily for 24 weeks added to methimazole did not change response or relapse rates compared with placebo.Double-Blind, Placebo-Controlled, Randomized Trial of Selenium in Graves Hyperthyroidism.
- In 68 overweight or obese women with underactive thyroid, 12 weeks of zinc alone or with selenium raised some thyroid hormones (free T3, and free T4 with lower TSH when combined with selenium), but there were no significant differences between groups for most measures.Effects of Zinc and Selenium Supplementation on Thyroid Function in Overweight and Obese Hypothyroid Female Patients: A …
- In 68 people on hemodialysis, 200 mcg of selenium daily for 12 weeks lowered reverse T3 compared with placebo, but did not change free T3, free T4 or TSH.Effects of Selenium and/or N-Acetyl-Cysteine Supplementation on Nonthyroidal Illness Syndrome in Hemodialysis Patients: …
- In 62 very low birth weight infants, adding trace elements to fortified human milk raised zinc intake, but zinc deficiency was rare and the abstract reports no thyroid result.Nutrition of very low birth weight infants fed human milk with or without supplemental trace elements: a randomized cont…
- In 61 euthyroid women with thyroid antibodies, 200 mcg of selenite daily for 6 months raised selenium levels but did not change antibody levels, thyroid-stimulating hormone or quality of life compared with placebo.Selenite supplementation in euthyroid subjects with thyroid peroxidase antibodies.
- In 60 people with overt Graves disease, adding a combined L-carnitine and selenium supplement to methimazole brought antibody levels to normal sooner and lowered methimazole needs, but thyroid hormone levels did not differ from methimazole alone.Adding L-Carnitine and Selenium to Methimazole in Graves' Disease: A Prospective Randomized Trial on Thyroid Markers and…
- In 55 people with high thyroid-stimulating hormone after thyroid surgery, 1 mg iodine daily for 20 weeks delayed recovery: all iodine-treated bilateral surgery patients were hypothyroid at 6 months versus 38% of placebo patients.Iodine therapy for thyroidectomy patients exhibiting high thyroid-stimulating hormone values: a randomised study.
- In 55 adults with thyroid autoimmunity, 200 mcg of selenomethionine daily for 6 months lowered thyroid antibody levels, while placebo did not.A randomized-controlled, double-blind study of the impact of selenium supplementation on thyroid autoimmunity and inflam…
- In 49 children with autoimmune thyroiditis, 12 months of sodium selenite at 100 or 200 mcg daily, added to a med, did not lower thyroid peroxidase antibodies.Selenium supplementation does not decrease thyroid peroxidase antibody concentration in children and adolescents with au…
- In 48 healthy young men given 500 mg or 250 mg of alpha glycerylphosphorylcholine daily for 7 days, thyroid stimulating hormone was lower with the 500 mg dose than with the other treatments, and strength and alertness did not differ between groups, but jump power improved most with 250 mg.Evaluation of the effects of two doses of alpha glycerylphosphorylcholine on physical and psychomotor performance.
- In 47 adults with autoimmune thyroiditis, 200 mcg of selenium daily lowered thyroid antibodies over 3 months, and antibodies rose again when selenium was stopped in the follow-up phase.Selenium in the treatment of autoimmune thyroiditis.
- In 45 women with thyroiditis in pregnancy, 83 mcg of selenium daily lowered thyroid autoantibodies compared with placebo, with antibodies rebounding in the placebo group after delivery.Selenium supplementation in the management of thyroid autoimmunity during pregnancy: results of the "SERENA study", a ra…
- In a small pilot study, 150 micrograms per day of iodine during pregnancy did not change the two-year neurodevelopment scores of 44 children compared with controls, and higher PCB 118 exposure may have offset any benefit.Neurotoxicant exposure during pregnancy is a confounder for assessment of iodine supplementation on neurodevelopment out…
- In 42 people with newly diagnosed Graves' hyperthyroidism, adding selenium and vitamin D to methimazole for 180 days lowered thyroid hormone levels faster and improved quality of life more than methimazole alone.Add-On Effect of Selenium and Vitamin D Combined Supplementation in Early Control of Graves' Disease Hyperthyroidism Dur…
- In 41 critically ill sepsis patients, selenium given for 2 weeks improved outcomes and restored selenium levels, but did not directly change free or total thyroid hormone levels compared with placebo.Selenium substitution has no direct effect on thyroid hormone metabolism in critically ill patients.
- In 40 children with autoimmune thyroid disease, 12 weeks of 25 mg daily elemental zinc did not change thyroid antibodies, thyroid tests or oxidative stress, but children given zinc needed no increase in a med dose, while the standard-therapy group did.Effect of daily zinc supplementation for 12 weeks on serum thyroid auto-antibody levels in children and adolescents with…
- In 40 critically ill septic patients, high-dose selenium for 3 days raised blood selenium and antioxidant enzyme levels but did not reduce oxidative damage, and thyroid test results were not reported as improved.Effect of selenium supplementation on biochemical markers and outcome in critically ill patients.
- In 40 people with Graves' disease and mild active eye involvement, a Mediterranean diet providing about 178 mcg of selenium daily for 24 weeks improved eye symptom scores compared with a free diet, but thyroid function did not differ between groups.Mediterranean diet, selenium and Graves' ophthalmopathy: a prospective, randomized, single-center study.
- In 40 adults with Hashimoto's thyroiditis, 200 mcg of selenium from enriched yeast for 60 days significantly lowered a blood marker of oxidative stress, but thyroid antibody and hormone levels did not change significantly compared with placebo.Effect of Selenomethionine- Enriched Yeast on Hypothyroidism Patients.
- In 37 infants having heart surgery, a skin antiseptic containing iodine (povidone-iodine) given before surgery did not clearly lower thyroid hormones afterward; the heart bypass itself had the larger effect on thyroid hormones.Thyroid function in infants following cardiac surgery: comparative effects of iodinated and noniodinated topical antisep…
- In 36 people with Graves' disease, radioactive iodine treatment was followed by rising thyroid antibody levels and myxoedema in 5 of 16 treated people, while propylthiouracil had milder effects.Thyroid stimulating antibodies, thyroglobulin antibodies and serum proteins during treatment of Graves' disease with rad…
- In 36 people with autoimmune thyroiditis, 200 mcg of sodium selenite daily for 3 months did not lower thyroid antibodies or change immune cytokine patterns compared with placebo.No immunological benefit of selenium in consecutive patients with autoimmune thyroiditis.
- In a placebo-controlled trial of 36 elderly nursing home residents, selenium raised selenium levels and lowered thyroxine, while placebo changed nothing.Low selenium status in the elderly influences thyroid hormones.
- In 31 critically ill trauma patients given selenium for 5 days, adding 13 mg zinc (with vitamin E) produced no additional change in thyroid hormones beyond selenium alone.Influence of selenium supplements on the post-traumatic alterations of the thyroid axis: a placebo-controlled trial.
- In 30 people with mild Graves' orbitopathy, 100 mcg selenium taken twice daily for 6 months reduced eye disease activity compared with placebo.Oral selenium improved the disease activity in patients with mild Graves' orbitopathy.
- In 29 people with multiple sclerosis, 12 weeks of a histamine and caffeine blend was well tolerated with no laboratory abnormalities reported, including thyroid stimulating hormone tests, but thyroid function was only checked for safety and no thyroid benefit was reported.A double-blind pilot study of the effect of Prokarin on fatigue in multiple sclerosis.
- In 28 overweight or obese adults on a calorie-restricted diet, 8 weeks of 25 mg daily zinc gluconate plus selenium did not change thyroid function compared with placebo.The Effects of Zinc and Selenium Co-Supplementation on Resting Metabolic Rate, Thyroid Function, Physical Fitness, and F…
- In 25 people with inactive moderate to severe Graves' eye disease, 200 micrograms of selenium daily for six months widened the eyelid opening more than placebo, with no significant change in eye movement or quality of life.Selenium supplementation in inactive moderate to severe Graves' orbitopathy patients: a randomized controlled trial.
- In 18 healthy adults, iodine from the seaweed Gracilaria verrucosa was absorbed better than from Laminaria hyperborea, with absorption of 85% to 101% versus 61.5% to 90%.Bioavailability of seaweed iodine in human beings.
- In a single-dose study of 12 healthy adults, a zinc-bound form of liothyronine (50 mcg) produced a lower but longer-lasting rise in blood T3 than standard liothyronine, with no tested health outcome.Extended Absorption of Liothyronine from Poly-Zinc-Liothyronine: Results from a Phase 1, Double-Blind, Randomized, and C…
- In 11 healthy men on a high-selenium diet of 297 mcg daily for about 17 weeks, blood thyroid hormone T3 fell and TSH rose compared with the low-selenium diet, along with lower sperm motility.Effects of dietary selenium on sperm motility in healthy men.
- In seven competitive cyclists, 22 mg of zinc daily for 30 days did not change thyroid hormone levels, although insulin rose later on.Plasma zinc, copper, and serum thyroid hormones and insulin levels after zinc supplementation followed by placebo in com…
- In severely iodine-deficient Zaire villages, single doses of potassium iodide had small and inconsistent effects on thyroxine levels, while oral iodized oil worked about as well as injected oil eight months later.Iodine supplementation: comparison of oral or intramuscular iodized oil with oral potassium iodide. A controlled trial i…
- In 110 people with Down's syndrome given zinc for about a year, thyroxine was lower and thyroid-stimulating hormone higher than before treatment, so thyroid function did not improve.Thyroid function and plasma immunoglobulins in subjects with Down's syndrome (DS) during ontogenesis and zinc therapy.
- In 90 people with heart disease living at altitude, 6 months of sodium selenite with vitamin E raised blood selenium and lowered malondialdehyde, and 31 of 42 treated people (73.81%) returned to normal thyroid hormone levels; the dose was not stated.[Influence of oral sodium selenite and vitamin E on thyroid hormones in patients with cardiovascular disease at altitude…
- In 86 people with Hashimoto's thyroiditis, 200 mcg selenomethionine daily for 3 or 6 months did not change anti-TPO antibodies but did lower anti-thyroglobulin antibodies.Selenomethionine treatment in patients with autoimmune thyroiditis: a prospective, quasi-randomised trial.
- In 55 people with non-toxic goitre, 5 days of furosemide 40 mg daily raised radioactive iodine uptake by about 58%, a larger increase than the 17% seen with a 14-day low-iodine diet.Read the study on PubMed (12845488) →
- In 52 adults with low blood selenium given 10 to 40 micrograms of selenium daily for 20 weeks, thyroxine levels fell in the supplemented groups, but the drop differed from placebo only in the 10-microgram group.An estimation of selenium requirements for New Zealanders.
- In 52 schoolchildren in an iodine and selenium deficient area of Zaire, 50 mcg of selenium daily for 2 months lowered blood T4, free T4 and reverse T3 without changing T3 or TSH, so the effect on thyroid function was mixed.Effect of selenium supplementation on thyroid hormone metabolism in an iodine and selenium deficient population.
- In children with Down syndrome, zinc sulfate supplements restored plasma zinc, TSH and reverse T3 levels that had been abnormal, though the study duration was not stated.Modulation of the neuroendocrine system and immune functions by zinc supplementation in children with Down's syndrome.
- In 47 women with Hashimoto's thyroiditis and low vitamin D, those already taking 200 mcg daily of selenomethionine saw larger drops in thyroid antibodies when given vitamin D for 6 months than women not taking selenium, though thyroid hormone levels did not change.Selenomethionine potentiates the impact of vitamin D on thyroid autoimmunity in euthyroid women with Hashimoto's thyroid…
- In 46 people with Graves disease, Lugol's iodine taken before surgery lowered blood flow within the thyroid, though changes in blood flow did not always match what surgeons heard.[Ultrasonographic evaluation of thyroid tissue perfusion in patients with Graves-Basedow disease as preparation for surg…
- In 46 head and neck cancer patients, nutritional counseling during radiotherapy was not shown to prevent underactive thyroid, and baseline thyroid-stimulating hormone and ferritin were the main predictors of it.The impact of nutritional counseling on thyroid disorders in head and neck cancer patients after (chemo)radiotherapy: re…
- In 44 newborns, selenium-enriched formula raised blood selenium over three months, but the abstract reports no thyroid result.Selenium status of New Zealand infants fed either a selenium supplemented or a standard formula.
- In 21 people with an overactive thyroid, 150 mg of potassium iodide daily for 3 to 7 weeks lowered thyroid hormone levels, but the effect was variable and unpredictable, and it did not meaningfully change how thyroid hormones are broken down in the body.The effect of iodide on serum thyroid hormone levels in normal persons, in hyperthyroid patients, and in hypothyroid pat…
- In 32 women taking 400 micrograms of selenium daily for 15 weeks while eating fish, blood arsenic rose with fish intake, and the link between arsenic and thyroid hormone balance changed with selenium, so the thyroid effect is unclear.Fish arsenic may influence human blood arsenic, selenium, and T4:T3 ratio.
- In a crossover study of 20 people, a med alone suppressed thyroid-stimulating hormone more than a med with 100 micrograms of iodide over 8 weeks, while 12 of 20 people with goitre had a smaller thyroid after 4 weeks.[Thyroxine vs iodine and thyroxine. Comparison of the TSH suppression test].
- In seven healthy adults, chromium picolinate taken with a single a med thyroid hormone dose significantly reduced how much of the hormone was absorbed over six hours, so people on meds should separate the two by several hours.Read the study on PubMed (17725434) →
- In Down syndrome children with low blood zinc, zinc sulfate supplementation for 6 months lowered TSH from about 4.0 to 2.6 mIU/mL, bringing it to levels similar to children with normal zinc.Zinc sulfate supplementation improves thyroid function in hypozincemic Down children.
- In 80 women with Hashimoto's thyroiditis, 200 mcg selenium daily for 6 months lowered anti-TPO antibodies by about 21% over the year, with no placebo group.Effects of 12 months treatment with L-selenomethionine on serum anti-TPO Levels in Patients with Hashimoto's thyroiditis…
- In 64 pregnant women treated with a 7-day iodine vaginal suppository, newborns showed no signs of an underactive thyroid when checked 4 to 5 days after delivery.[Clinical significance of betadine vaginal suppository treatment in pregnancy].
- In 40 hemodialysis patients, eating one Brazil nut daily for three months raised selenium, free thyroxine and triiodothyronine levels, though triiodothyronine did not return to normal.EFFECT OF SELENIUM SUPPLEMENTATION VIA BRAZIL NUT (BERTHOLLETIA EXCELSA, HBK) ON THYROID HORMONES LEVELS IN HEMODIALYSIS…
- In 28 healthy adults taking 200 mcg of selenomethionine daily for about 28 months, thyroid hormone levels showed no clinically significant change.Effects of selenomethionine supplementation on selenium status and thyroid hormone concentrations in healthy adults.
- In 23 children with early autoimmune thyroiditis, 50 micrograms of selenium daily for 3 months did not change thyroid antibodies, but 35 percent of children had their thyroid shrink by 30 percent or more.Effects of selenium supplementation in the early stage of autoimmune thyroiditis in childhood: an open-label pilot study…
- In 22 people with normal thyroid function, iodine contrast dye given for scans caused a temporary rise in thyroid-stimulating hormone within the first week, and four people went above the normal range.Do iodine-containing contrast media induce clinically relevant changes in thyroid function parameters of euthyroid patie…
- In 21 people with early autoimmune thyroiditis, six months of myo-inositol with selenium lowered TSH and thyroid antibody levels, with no placebo group.Myo-inositol and selenium reduce the risk of developing overt hypothyroidism in patients with autoimmune thyroiditis.
- In 10 healthy men taking 27 mg of iodine daily for 4 weeks, the thyroid gland enlarged and thyroid-stimulating hormone rose, and both returned to baseline within a month after stopping.Evidence of thyroid volume increase in normal subjects receiving excess iodide.
- In 10 sedentary young men, 4 weeks of oral zinc sulfate supplements prevented the drop in thyroid hormone levels that followed bicycle exercise, though zinc did not raise thyroid hormones at rest beyond the pre-supplement values.Effect of fatiguing bicycle exercise on thyroid hormone and testosterone levels in sedentary males supplemented with ora…
- In 10 people on hemodialysis, six months of oral sodium selenite raised free T3 and lowered TSH, with no placebo group.Thyroid function and plasma selenium in chronic uremic patients on hemodialysis treatment.
- In five people with neurological endemic cretinism, giving iodide caused signs of an underactive thyroid, suggesting a hidden weakness in thyroid hormone production.Effects of iodides on the hypothalamic-pituitary-thyroid axis in neurological endemic cretinism: evidence for compensate…
- In five people with a gene mutation affecting selenoprotein production, selenium supplements raised blood selenium but did not correct their abnormal thyroid function tests.Selenium supplementation fails to correct the selenoprotein synthesis defect in subjects with SBP2 gene mutations.
- In a large cohort of over 566,000 adults, dietary zinc intake was not clearly linked to thyroid cancer risk.The association between selenium and other micronutrients and thyroid cancer incidence in the NIH-AARP Diet and Health S…
- In 4,771 community adults with normal thyroid tests, higher blood choline was linked to higher TSH, a sign of lower-normal thyroid function, and this link was stronger in people with fatty liver.Lower Thyroid Function and Higher Plasma Choline: Effect Modification by Metabolic Dysfunction-Associated Steatotic Live…
- In a survey of 2,582 US adults, low caffeine intake was linked to higher thyroid-stimulating hormone, while moderate intake (about 10 to 265 mg per day) was linked to lower levels in people with metabolic disorders, with the findings being inconsistent in direction.Relationship between caffeine intake and thyroid function: results from NHANES 2007-2012.
- In 2041 pregnant women at 12 weeks, those taking selenium, zinc and copper supplements were about 1.46 times less likely to have elevated thyroid peroxidase antibodies, though plasma selenium was negatively related to free thyroxine.Plasma mineral (selenium, zinc or copper) concentrations in the general pregnant population, adjusted for supplement int…
- In a large French cross-sectional study, higher selenium levels were linked to smaller thyroid volume and lower goiter risk in women, with no such link found in men.Association of selenium with thyroid volume and echostructure in 35- to 60-year-old French adults.
- In 1802 healthy children and adolescents in Germany, many had urine iodine below the WHO target, but iodine levels did not correlate with thyroid hormone levels or thyroid antibodies.Spot urine iodine levels below the WHO recommendation are not related to impaired thyroid function in healthy children a…
- In children aged 8 to 12 in western Poland, goiter cases fell from 35.4% in 1992 to 6.3% in 2005 after salt iodization, though antibody levels rose in some children.Changes in thyroid morphology and function in children in western Poland as a result of intensified iodine prophylaxis.
- In 1022 pregnant Chilean women in the first trimester, iodine intake was adequate, but about 6% had clinical or subclinical hypothyroidism, a higher rate than in the literature.Thyroid-Stimulating Hormone Reference Ranges in the First Trimester of Pregnancy in an Iodine-Sufficient Country.
- In children in areas with high iodine in drinking water, goitre prevalence fell from 24.6% to 5.9% after iodized salt was removed from their diet for about one and a half years.[Influence of removing iodized salt on children's goiter status in areas with high iodine in drinking water].
- In a population study of 856 adults plus 16 volunteers given thyroid hormone, a thyroid hormone metabolite was not tied to classic thyroid function, while caffeine and its breakdown products were the strongest signal linked to coffee intake.A Thyroid Hormone-Independent Molecular Fingerprint of 3,5-Diiodothyronine Suggests a Strong Relationship with Coffee Me…
- In 741 pregnant women in China, higher blood iodine was linked to higher free and total thyroxine levels, while its link to free triiodothyronine was curved, peaking at intermediate levels.Serum iodine concentration in pregnant women and its association with thyroid function.
- In 726 mother-infant pairs, prenatal triclosan exposure was linked to birth measures, with thyroid hormones and choline among the factors that appeared to mediate these links.Multiple mediation effects on association between prenatal triclosan exposure and birth outcomes.
- In a survey of 625 school-age children in northern Cyprus, no child had a thyroid larger than the recommended limit, and most had adequate iodine intake, with a median urinary iodine of 120 micrograms per liter.Iodine status and thyroid volumes of school age children from Northern Cyprus.
- In 608 people newly diagnosed with papillary thyroid cancer, urinary zinc levels were not reported as linked to tumor aggressiveness; men had higher zinc than women.Associations between essential microelements exposure and the aggressive clinicopathologic characteristics of papillary …
- In 399 older heart patients in São Paulo, about 1 in 14 had an overactive thyroid and about 1 in 12 had an underactive thyroid, and about 31% had urinary iodine above the excessive-intake level of 300 micrograms per liter; the study did not test iodine supplementation.The prevalence of thyroid dysfunction in elderly cardiology patients with mild excessive iodine intake in the urban area…
- In a case-control study of 197 people with thyroid tumor or goiter and 197 matched healthy controls, higher chromium levels were linked to lower risk, but cadmium and mercury showed mixed effects on thyroid function.A case-control study on the association of mineral elements exposure and thyroid tumor and goiter.
- In 387 middle-aged and older adults, red blood cell zinc was only weakly and negatively related to total T4 thyroid hormone levels.Basal metabolic rate and thyroid hormones of late-middle-aged and older human subjects: the ZENITH study.
- In 387 healthy men aged about 77, higher selenium status was linked to better bone mineral density but not to thyroid hormone levels.Selenium Status Is Positively Associated with Bone Mineral Density in Healthy Aging European Men.
- In 365 pregnant women in New York City, those offered 150 mcg of potassium iodide daily had higher urine iodine (170 vs 128 mcg/L) and less risk of iodine deficiency (23% vs 39%), though over 20% of supplemented women were still at risk.Apparent insufficiency of iodine supplementation in pregnancy.
- In 334 pregnant women in southern India, iodine status was adequate, yet 18% had thyroid insufficiency, with overweight and anemia predicting it.High prevalence of maternal hypothyroidism despite adequate iodine status in Indian pregnant women in the first trimeste…
- After mandatory iodized salt was introduced in a severely iodine-deficient area of Turkey, goiter prevalence in 304 schoolchildren fell (19.4% by palpation, 14.6% by ultrasound) and the area became only mildly iodine-deficient within 3 years.Effect of iodine supplementation on goiter prevalence among the pediatric population in a severely iodine deficient area…
- In 237 people with overactive thyroid treated with low-dose radioactive iodine plus 12 to 18 months of antithyroid drugs, 83% had clinical remission and 0.8% developed lasting underactive thyroid.[Treatment of diffuse toxic goiter with radioactive iodine in combination with prolonged antithyroid therapy].
- In 219 men, blood chromium was not linked to thyroid stimulating hormone levels, although it was positively linked to prolactin, while arsenic and lead and copper showed other thyroid-related patterns.Multiple metals predict prolactin and thyrotropin (TSH) levels in men.
- Thyroid autoimmunity was more common in women with breast cancer than in controls, and thyroid autoimmunity did not affect survival, though higher serum selenium was linked to worse relapse-free survival.Thyroid autoimmunity occurs more frequently in women with breast cancer compared to women with colorectal cancer and con…
- In 200 people, blood selenium levels were similar in those with and without thyroid nodules, so no link between selenium and nodules was found.Serum Selenium Levels in Euthyroid Nodular Thyroid Diseases.
- Egyptian women with autoimmune subclinical hypothyroidism had higher urine iodine than healthy controls, and within the patients higher iodine went with higher thyroid-stimulating hormone.Excess urinary iodine is associated with autoimmune subclinical hypothyroidism among Egyptian women.
- In 133 Spanish adolescent boys, higher urinary chromium was associated with lower thyroid-stimulating hormone levels, a association whose health meaning is unclear.Association of urinary metal concentrations with blood pressure and serum hormones in Spanish male adolescents.
- In a retrospective review of 130 people having thyroid surgery, serum zinc levels did not differ significantly between those with papillary thyroid cancer and those with benign disease; copper was higher in the cancer group.Copper as ancillary diagnostic tool in preoperative evaluation of possible papillary thyroid carcinoma in patients with …
- Among 129 people with cystic fibrosis, 83.7% had low iodine levels and 11.6% had subclinical hypothyroidism, though no link to age, weight, nutrition or lung function was found.Iodine deficiency and subclinical hypothyroidism are common in cystic fibrosis patients.
- Thyroid tissue from people with nodular goitre contained less copper than tissue from healthy autopsy thyroids.Determination of cadmium, cobalt, copper, iron, manganese, and zinc in thyroid glands of patients with diagnosed nodular…
- In 110 pregnant women in the Paris area, lower iodine levels were linked to smaller fetal thyroid glands, and widespread iodine deficiency was found.Iodine deficiency in northern Paris area: impact on fetal thyroid mensuration.
- In 110 people in Iran, blood chromium levels were higher in patients with thyroid disease, and chromium was linked to a higher risk of hypothyroidism, hyperthyroidism, and thyroid cancer in this observational study.Thyroid dysfunction: how concentration of toxic and essential elements contribute to risk of hypothyroidism, hyperthyroi…
- In 107 patients scheduled for thyroid surgery, a choline-based PET tracer showed diffuse uptake in most people with autoimmune thyroiditis, and uptake strength tracked inflammation, fibrosis and antibody levels.Thyroid 18F-fluorocholine uptake in patients with chronic autoimmune thyroiditis.
- Among 105 patients treated with radioactive iodine for overactive thyroid, 81% were clinically euthyroid at follow-up, and raised TSH levels in about half of the euthyroid patients did not progress to overt hypothyroidism over 12 months.Thyroid function in patients treated with radioactive iodine for thyrotoxicosis.
- Women with newly diagnosed subclinical hypothyroidism had a higher copper to zinc ratio and a higher copper to magnesium ratio than healthy women.Association Between Low Circulating Omentin-1, Vitamin D, Antioxidants, and Trace Elements Imbalances in Women with Subc…
- In people exposed to dioxins, thyroid disease was more common, but caffeine was only used as a test to measure liver enzyme activity, and that enzyme activity was not linked to thyroid disease.Cytochrome P450 1A2 activity and incidence of thyroid disease and cancer after chronic or acute exposure to dioxins.
- In 67 adults with an overactive or underactive thyroid, blood zinc levels showed no clear link to thyroid activity.Free amino acids, copper, iron and zinc composition in sera of patients with thyrometabolic diseases.
- In a case-control study of 30 pregnant women with low thyroid function matched to 30 controls, higher blood chromium was associated with a somewhat greater risk of gestational hypothyroidism, with an odds ratio of 1.11.Association of metal mixtures during the second trimester with gestational hypothyroidism and its mediation by metabolit…
- In 54 rural Brazilian children exposed to pesticides and metals, higher blood chromium was linked to higher levels of the thyroid-stimulating hormone and lower free thyroxine, which points to poorer thyroid function.Exposure to environment chemicals and its possible role in endocrine disruption of children from a rural area.
- In a study of 50 people, serum zinc was lower in thyroid cancer patients than in controls both before and after surgery, while zinc was higher in thyroid tissue; this study did not give zinc and so does not show an effect of zinc on thyroid health.Changes in the Serum Levels of Trace Elements Before and After the Operation in Thyroid Cancer Patients.
- Of 47 people with lung metastases from thyroid cancer, 28 showed radioactive iodine uptake in the tumors, and those with less severe underactive thyroid after surgery were more likely to show this uptake.Increased uptake of iodine-131 in metastases of differentiated thyroid carcinoma associated with less severe hypothyroid…
- In a retrospective review of 45 Chinese adults admitted with thyrotoxic periodic paralysis, about one quarter had normal red blood cell zinc levels; this was not a zinc supplement study.Thyrotoxic periodic paralysis in a Chinese population.
- Women with thyroid gland disease had lower serum selenium levels than healthy controls, with the lowest levels in the hyperthyroid group.[Selenium concentration in serum of women with thyroid gland disease].
- In 38 retrospectively reviewed thyroid cancer patients with raised thyroglobulin but no visible disease, extra high-dose radioactive iodine treatment was followed by normal thyroglobulin levels in 6 patients over 8 to 46 months, and the long-term effect on survival was unclear.I-131 therapy for thyroglobulin positive patients without anatomical evidence of persistent disease.
- In a small pilot of 20 people, those with head and neck tumors or thyroid disease had blood heavy metal and PCB levels at least twice the reference maximum, while healthy volunteers did not; chromium was not reported separately.The role of heavy metals and polychlorinated biphenyls (PCBs) in the oncogenesis of head and neck tumors and thyroid dis…
- Among five team members exposed to a radioactive plume in Fukushima, those who took two potassium iodide pills about 36 hours before exposure showed an inverse link between age and thyroid radioactivity, suggesting stable iodine may have a protective effect.A Study of Thyroid 131I Activity of Five Human Subjects Exposed to a Radioactive Plume at Tamura City in Fukushima.
- In a case-control study in India, people with hypothyroidism had higher urinary iodine and anti-TPO antibody levels than matched controls, which the authors interpret as an association between excess iodine intake and hypothyroidism.Does iodine excess lead to hypothyroidism? Evidence from a case-control study in India.
- This study tested a zinc measurement kit and found red blood cell zinc was lower in Graves' disease than in silent thyroiditis, helping tell the two apart; it did not test any supplement.Measurement of red blood cell zinc concentration with Zn-test kit: discrimination between hyperthyroid Graves' disease a…
- In a 1977 study, people with overactive thyroid excreted more zinc in urine than healthy people, and the extra loss tracked with how severe the thyroid-driven metabolic response was; no supplement was tested.Zinc metabolism and thyroid status.
- Both too little and too much of trace elements, including chromium, were linked to goiter, and living in carbonate rock areas was associated with more thyroid disease.[Hair trace elements in patients with goiter].
- People with goiter had lower blood selenium and thyroid hormone levels than healthy controls, and the abstract does not report the effect of 6 months of selenium plus iodine supplementation.Effects of selenium supplementation on iodine and thyroid hormone status in a selected population with goitre in Pakista…
- In 20 men with autoimmune thyroiditis and normal thyroid function, 6 months of 83 mcg daily selenium raised free thyroxine and improved sperm parameters, while the thyroid-stimulating hormone did not change significantly.Effects of Selenium Supplementation on Sperm Parameters and DNA-Fragmentation Rate in Patients with Chronic Autoimmune T…
- In goitrous patients, a single yearly dose of an iodised oil containing 376 mg iodine per mL was reported to normalise thyroid function within 3 months in early-stage goitre.Brassiodol, a new iodised oil for goitrous patients.
- In patients with thyroid cancer, a diagnostic iodine scan reduced thyroid uptake of the later therapeutic radioactive iodine dose, with the effect larger for iodine-131 than iodine-123 and greatest when the two doses were about 25 days apart.Self-stunning in thyroid ablation: evidence from comparative studies of diagnostic 131I and 123I.
- In children with normal thyroid function, sodium iodide at 1500 to 2000 micrograms per square meter of body surface per day maximally suppressed thyroid uptake of radioactive iodine, and the suppression reversed when the iodide was stopped.Minimal dosage of iodide required to suppress uptake of iodine-131 by normal thyroid.
- In a 1977 animal study in male albino rats, chromium added to food across a wide range of doses affected thyroid gland structure and function, and the lowest dose tested, about 3 micrograms per kilogram of body weight, was judged the most physiological.[Thyroid gland morphological and functional indices in the experimental action of chromium].
Review Totals and Summary
Members Only334 reviews · 84% positive
334 reviews · Amazon 334
84% positive8% neutral8% negative
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Biohacker Summary
Members Only9 of 10 recommend it
9 of 10 biohackers on our panel recommend it
Zinc drew comments from all ten panelists: four recommend it, four use it, one warns, and the rest are neutral or mixed. Most of them link it to immune support and wound healing, and one also mentions testosterone, gut lining, sleep, and skin protection. The forms named are zinc carnosine for the gut and a zinc sunscreen applied to the skin; one pairs zinc with vitamin C for fall and winter, and another pairs it with magnesium. Doses are rare: one takes 15 mg in the morning, and one describes a short course around surgery for wound healing, while the one who warns says taking too much can lead to low copper. Caffeine is a smaller ingredient in this product, and the panel mostly talks about timing it earlier in the day, with two of them having stopped it for a time.
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Dr. Eric Berg · Zinc · recommends
- Recommends zinc as a trace mineral, noting that modern farming practices deplete it from the soil, leading to low levels in crops.
- Notes that sardines are rich in selenium, which binds with mercury.
- Recommends using povidone-iodine daily with a small bandage for skin tags and warts, stating it may help deactivate the virus behind these growths.
- Recommends selenium as a trace mineral, noting that modern farming practices deplete it from the soil, leading to low levels in crops.
- Recommends iodine as a trace mineral, noting that modern farming practices deplete it from the soil, leading to low levels in crops.
- Dr. Eric Berg states that 80% of the body's iodine is concentrated in the thyroid, but other tissues like breast tissue, reproductive organs, and stomach also rely on iodine to function properly, emphasizing the importance of getting enough iodine even with a normally functioning thyroid.
- Introduces his new product, Plant-based Iodine Icelandic Sea Kelp, which he uses and recommends taking one vegetable capsule delivering 200 micrograms of plant-based iodine in the morning.
- Notes that white spots on nails point to zinc deficiency, which is usually depleted by eating sugar and refined carbs.
- States that zinc greatly supports natural killer cells.
- States that the thyroid uses about 6 mg of iodine a day, and other tissues like breast tissue, ovaries, brain, stomach lining, and eyes also need iodine.
- Recommends ensuring adequate choline intake, as a deficiency can make one susceptible to liver fat, and it's important for preventing fat accumulation in the liver.
- States that zinc is needed to absorb magnesium.
- Recommends ensuring sufficient zinc intake because the prostate needs enough zinc for the conversion from testosterone to DHT to be smooth and optimized.
- Recommends choline for brain health, noting that consuming two eggs provides 300 mg of choline, which is essential for brain communication.
Dr. Rhonda Patrick · Zinc · neutral
- Mentions that getting too little zinc may play a role in declining testosterone levels, and that zinc helps the body make testosterone.
- Explains that caffeine can activate AMPK, a cellular energy sensor involved in fat burning and glucose regulation, which helps muscle cells take up glucose and promotes using fatty acids for energy.
- Recommends pairing caffeine with L-theanine to enhance alertness and focus while mitigating anxiety and jitteriness, suggesting a dose of 100 to 150 mg of caffeine.
- Recommends pairing coffee with L-theanine to enhance cognitive performance, noting that L-theanine can help balance caffeine’s stimulatory effects.
- Notes that not getting enough zinc can affect testosterone, as zinc is very important for testosterone synthesis.
- Recommends men take a 30 milligram zinc supplement for sperm health when preparing for IVF.
- Recommends cutting out caffeine in the three months before conception for both men and women, as it affects sperm.
- Discusses findings from a meta-analysis on zinc supplementation, noting it improved insulin resistance, inflammation, and oxidative stress in people with diabetes or prediabetes, and explains its biological role in the pancreas.
- Recommends caffeine for alertness and focus, especially when combined with L-theanine to smooth out the response and maintain cognitive benefits, suggesting a practical dose of 100-150 mg.
- States that choline helps make acetylcholine for cognition and phosphatidylcholine for cell membranes, and can be converted into betaine to help clear homocysteine.
- Recommends nutrients like zinc for men to prioritize sperm mitochondrial health.
- Recommends cutting down or eliminating caffeine when actively trying to conceive.
- Warns that a very high dose of caffeine, around 350 mg pre-workout, may blunt some of creatine's performance benefit due to opposite effects on muscle relaxation.
- Self-administers 350 mg of caffeine in a bolus right after returning from mass and his workout, and before eating, noting that he likes dark roast Starbucks.
Andrew Huberman · Zinc · neutral
- Notes that AG1 Pro contains zinc carnosine to support and improve the lining of the gut.
- Zinc carnosine to support and improve the lining of your gut.
- Notes that AG1 Pro contains zinc carnosine to support and improve the lining of the gut.
- Used caffeine, taking 400 milligrams, to improve his mood and physical vigor during mundane tasks like swimming, noting that it made life not so bad and allowed him to rip through the water.
- Mentions caffeine in a discussion about supplement use.
- Discusses caffeine timing as a tool related to sleep.
- He recommends caffeine, in coffee or tea form, or in tablet or capsule form at lower dosages than found in coffee and tea, as a reasonable way to explore stimulant-based approaches for enhancing cognitive function and focus.
- States that AG1 Pro contains zinc carnosine to support and improve the lining of the gut.
- Uses AG1 Pro, which contains zinc carnosine to support and improve the lining of the gut.
- Huberman states that caffeine can improve focus and concentration, with a general useful range of 100 to 400 milligrams, and most people do well with 100 to 200 milligrams prior to focused work.
- Discusses caffeine as a tool for improving attention, noting its impact on focus and sleep.
- States that AG1 Pro contains zinc carnosine to support and improve the lining of the gut, and he was already taking some of these ingredients separately.
- Mentions that coffee and tea produce caffeine, which were likely defense chemicals, and that plants learned it was better to alter consciousness than kill predators outright.
- Discusses caffeine and its health benefits.
Ben Greenfield · Zinc · warns
- Ben Greenfield's formulation includes 30 grams of zinc a day, taken for one week before surgery and two weeks after, as it is an important cofactor for wound healing.
- Mentions that overshooting zinc can lead to a copper deficiency, highlighting the interplay between these elements.
- Came off caffeine for a year after his separation.
- Quit caffeine in the same year he quit testosterone replacement therapy and alcohol.
- Uses caffeine, such as coffee or green tea, in his morning fasted fat-burning session to slightly increase the oxidation of fats.
- Advises against relying on caffeine for morning energy, suggesting that natural sugar-based stimulants combined with hydration and meditation can provide sufficient wakefulness.
- Recommends taking sufficient iodine to ensure free T3 levels are right, which is important for the reverse calcium transport system.
- Recommends taking sufficient selenium to ensure free T3 levels are right, which is important for the reverse calcium transport system.
- Mentions chromium as a secondary ingredient in blood sugar control products, along with vanadium and bittermelon extract.
- Emphasizes that zinc sufficiency is crucial for immunity because the thymus-derived peptide thymulin, which trains lymphocytes, requires zinc to be active.
- Recommends Caffeine, noting that it can improve focus, mood, and training, help control appetite, raise calories burned, and reduce fatigue.
- Recommends Beta-alanine, explaining it builds up carnosine in muscles, helping buffer acidity during hard efforts.
- Recommends adding zinc into one's stack because it is a co-factor for enzymes involved in testosterone synthesis and sperm maturation, and zinc deficiency is a reproducible cause of low sperm count.
- He mentions zinc as a supplement with real human data behind it for male fertility.
Dr. Mark Hyman · Zinc · neutral
- Explains that zinc is important for the body's repair crew, helping to heal damaged tissue, and a deficiency can lead to cuts and wounds taking longer to heal.
- Gave a patient with psoriatic arthritis a little zinc, which contributed to significant improvement in her condition.
- Discusses with patients their caffeine consumption, suggesting that too much caffeine can artificially increase their stress response.
- Recommends ensuring adequate zinc intake on a regular basis for immune support, noting some data on zinc lozenges for early cold.
- Includes selenium in a formula he uses to support health during the winter season.
- Recommends correcting nutrient deficiencies with zinc.
- Recommends stopping caffeine by noon.
- Recommends nutrient-dense foods rich in zinc, such as pumpkin seeds and oysters, to reduce inflammation.
- Recommends nutrient-dense foods rich in selenium, such as Brazil nuts and sardines, to reduce inflammation.
- Used zinc as part of a protocol to rebuild the gut microbiome and heal the gut of a nine-year-old girl with severe behavioral issues.
- States that caffeine's effect on ADHD depends on the person, as it can help focus but also activate irritation or stress, and its impact is related to individual caffeine metabolism.
- Notes that zinc supports immune health, helps wounds heal, and plays a key role in growth and tissue repair, and they measure it.
- Mentions zinc is needed for phase one liver functions and inflammation.
- Mentions copper is needed for superoxide dismutase.
Thomas DeLauer · Zinc · uses
- Adds zinc to their immunity duo because it helps them absorb vitamin C, considering the two together a fantastic combination for fall and winter.
- Recommends taking a low dose of caffeine later in the morning, around 7 or 8 a.m., after cortisol has settled and adenosine has started to build, to maximize its effect on blocking fatigue.
- Would consume more caffeine throughout the day to mobilize fat, emphasizing the importance of combining it with activity to oxidize the mobilized fat.
- If you can wait for your cortisol levels to play out, call it 30-60 minutes, then the caffeine is actually going to land when adenosine is reasserting and cortisol is falling, and you're going to get so much more out of your caffeine.
- Explains that caffeine from green tea mobilizes fatty acids, which can be converted into ketones, providing a ketone boost, especially in a fasted or low-carb state.
- Warns that treating brain fog with caffeine without addressing underlying inflammation is ineffective and likely to make the situation worse.
- Notes that caffeine significantly increased fat metabolism and fat oxidation during exercise, especially at lower intensities, and that adding coffee around an exercise bout led to more calories and fat burned.
- Says that caffeine significantly increased fat metabolism and that at low intensity cardio or exercise caffeine works better at mobilizing and utilizing fat.
- Might have some caffeine before fasted training.
- Recommends zinc, noting it is a cofactor for enzymes that build neurotransmitters, and deficiency can affect mood, happiness, and motivation.
- Recommends adding selenium to the diet, found in Brazil nuts (two or three a day), eggs, shellfish, and mushrooms, as the glutathione recycling process is very selenium dependent and it helps protect against feroptosis.
- Mentions that more zinc could be beneficial for testosterone, but it's not working on the axis that most people need help with.
- Recommends caffeine as a must on the fasting day to create a low-grade energy demand that forces the body to favor lipolysis.
- Mentions that choline from avocado (and eggs) contributes to the liver's ability to tag and process toxins, focusing on phase II detox.
Dave Asprey · Zinc · uses
- Developed a nonnano zinc sunscreen over five years, stating her skin is probably better now than it's ever been.
- Host Dave Asprey explores caffeine's effects on cardiovascular function, adenosine signaling, and inflammation, explaining why individualized responses matter more than blanket dietary restrictions.
- Loves coffee, has the caffeine molecule tattooed on his arm, drinks it every morning, and says it does amazing things for your brain and for how long you can live, but it can't clear most brain fog on its own.
- Created Danger Coffee, a mineral-enriched, lab-tested, mold-free coffee that delivers rich flavor and clean caffeine without all the junk, and recommends it to others.
- Dave Asprey's lab proved that caffeine is a flow hack and the only known substance to actually make you flow prone. Coffee will make you more flow prone.
- Dave explains why the 1:2 ratio of caffeine to L-theanine beats coffee alone for working memory, accuracy, and calm, sustained concentration.
- States that his entire career started on caffeine and he uses it every morning, but notes it's like a loan from your future self, leading to an afternoon crash.
- Dave Asprey's company used caffeine, which is a safe ingredient, but they stopped using it because it doesn't provide the type of results and change in the skin that newer ingredients do.
- Recommends increasing choline intake, noting that it is missing in most people's diets and is important for cell membranes and liver function. He switched to a new American-made, plant-based choline called Vitacoline, which has prenatal clinical studies.
- Dave Asprey recommends eating eggs or taking a supplement that raises acetylcholine when taking racetams, as racetams can burn through choline, which the brain needs for focus.
- Emphasizes the importance of having enough zinc before trying advanced longevity strategies like peptides.
- States that caffeine is one of his superpowers and increases the rate of ketone formation, which fuels neurons.
- Emphasizes the importance of having enough copper before trying advanced longevity strategies like peptides.
- Emphasizes the importance of having enough selenium before trying advanced longevity strategies like peptides.
Siim Land · Zinc · recommends
- States that deficiencies in nutrients such as zinc can impair normal immune regulation.
- Recommends stopping caffeine earlier to improve sleep.
- Notes that polyphenolic compounds in coffee, both decaf and regular caffeinated, can influence cellular stress pathways and have been seen to increase autophagy activity in mice, with regular coffee appearing more potent due to caffeine's additional energetic stress.
- Mentions that copper is a mineral necessary for making collagen.
- Recommends moving caffeine intake earlier in the day because having it too late can disrupt sleep, especially for slow metabolizers.
- Recommends not having caffeine after lunch, noting that 400 mg 4 hours before bed reduced deep sleep by approximately 30 minutes in a trial, although he personally has a fast caffeine metabolism.
- Warns that combining a large dose of glycine with caffeine can amplify negative experiences, as caffeine independently increases arousal and can cause restlessness, anxiety, and increased heart rate.
- States that regular coffee promotes visceral fat loss, and going from low or zero intake to moderate intake increases fat loss due to caffeine and polyphenols.
- States that deficiencies in nutrients such as selenium can impair normal immune regulation.
- Recommends chromium as a mineral that can lead to better body composition.
- States that selenium is one of many other nutrients needed for glutathione.
- Would take chromium for pre-diabetes.
- Suggests that higher caffeine intake might be useful for older people because caffeine raises cortisol, and consuming it in the morning contributes to circadian regulation.
- Explains that zinc raises testosterone only if zinc status or testosterone levels are low, and can reduce the duration and severity of colds and flu, and lower blood sugar and lipids if zinc status is low.
Bryan Johnson · Zinc · uses
- Takes 15 mg of Zinc in the morning for longevity.
- Drinks coffee when starting to fade, ensuring the last cup is between 10 and 12 hours before bed so caffeine doesn't affect sleep.
- Used 300 mg of caffeine in the morning as part of their jet lag recovery.
- Uses 300 mg of slow release caffeine in the morning as part of a jet lag recovery protocol.
- Notes that coffee affects the gut, which then affects the brain, and that it is the coffee bean, not the caffeine, doing most of the work.
- Takes 15 mg of Zinc in the morning.
- Takes 15 mg of Zinc in the morning for longevity.
- Takes 2 mg of Copper in the morning for longevity.
- Notes that the culture in DC involves running on caffeine, along with alcohol and sleep deprivation, leading to poor nutrition and an unhealthy environment.
- Warns that caffeine has a 6-hour half-life, so consuming it later in the day will leave a significant amount in the body at bedtime, recommending consumption earlier in the day.
- Recommends consuming no caffeine past noon due to its 6-hour half-life, suggesting that if sleep is nailed, caffeine might not be needed.
- Warns against stimulants like caffeine for sleep, advising to have the last cup of coffee before noon if going to bed at 10:00 p.m.
- Advises that if one is going to drink caffeine, they should try to have it earlier in the day and experiment to find the right time that doesn't disrupt their sleep.
- Has stopped all caffeine, as it has helped him improve his sleep.
Peter Attia · Zinc · recommends
- Suggests that zinc and magnesium could potentially help with vasodilation and sleep, particularly for women experiencing severe symptoms in the luteal phase.
- States that he needs two to three times the normal dose of any medication or drug to feel an effect, including caffeine, and can drink four cups of coffee without feeling anything.
- Mentions data suggesting caffeine might be more helpful in the luteal phase to help with fatigue components.
- Peter Attia, who did not believe in dietary supplements as a collegiate athlete, later dove into understanding the impacts of beta-alanine during grad school.
- Uses caffeine in combination with Alpha GPC, MCT, and Theanine, often adding it to coffee for long periods of cognitive work.
- Finds Alpha GPC works well with caffeine, and he puts a product containing Alpha GPC, MCT, and caffeine into his coffee for long periods of cognitive work.
- Discusses the dangers of supplementing with high levels of iodine.
- Warns that high-dose iodine supplementation carries a risk of autoimmune thyroid disease, citing increased incidence in Japan due to higher dietary iodine intake.
- Notes that several studies show patients taking selenium can reduce TPO levels and prolong the honeymoon period of Hashimoto's disease.
- Mentions that experimenting with the timing of caffeine is a great idea for sleep.
- Warns that decaffeinated coffee can contain significant amounts of caffeine and advises cutting off all coffee, including decaf, by 11 a.m. for better sleep quality.
- Explains that caffeine is problematic because it blocks adenosine receptors, leading to a 'caffeine crash' when it wears off and adenosine floods the receptors, causing sleepiness.
- States that caffeine does not wake him up, which contributed to his belief that he did not have an addiction gene.
- States that caffeine does not wake him up.
RAL Summary
Members OnlyTier 4 for Thyroid Health
The tier rests on zinc, a trace mineral added to a pre-workout, and the strong zinc finding was for zinc combined with magnesium and vitamin A, while zinc alone gave only low-certainty and inconsistent results and the product's main ingredients have no thyroid evidence. So it is graded Tier 4, lower than the rules alone gave.
Take 4 servings a day (4 scoops) to match the dose that worked in the studies.
- Emerging: not enough evidence to rank higher yet.
Where the evidence disagrees: 76 of the 168 human studies found no effect.
More Details
Members OnlyBody systems · Combine with · Possible side effects
Body systems: Endocrine system, Nervous system, Muscular system
Possible side effects: Chromium taken with thyroid hormone medicine reduced its absorption, and high iodine intake can enlarge the thyroid or slow recovery after thyroid surgery. One review reported a higher risk of side effects with selenium.
Supplement Facts
Iodine 225 mcg · Zinc 15 mg · Selenium 55 mcg
Supplement Facts
Serving Size 1 Scoop (13.7g)
Servings Per Container 30
Amount Per Serving% Daily Value
| Calories | 5 | |
| Iodine | 225 mcg | |
| Zinc | 15 mg | |
| Selenium | 55 mcg | |
| Copper | 1 mg | |
| Chromium | 200 mcg | |
| Citrulline Malate 2:1 | 6,000 mg | † |
| Beta-Alanine | 2,000 mg | † |
| Betaine Anhydrous | 1,500 mg | † |
| Acetyl L-Carnitine HCl | 1,000 mg | † |
| Choline Bitartrate | 500 mg | † |
| L-Theanine | 180 mg | † |
| PurCaf® Organic Caffeine | 180 mg | † |
| Theobromine | 50 mg | † |
| Bioperine® | 5 mg | † |
| Huperzine A | 100 mcg | † |
† Daily Value not established.
Other ingredients: Natural Flavors (900mg), Stevia Extract (350mg), Calcium Silicate (305mg), Silicon Dioxide (305mg), Rebaudioside M (from stevia extract) (105mg).
Barcode (UPC) 602773999460 · Label source: Reverseagelab · Report a label change
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Graded November 11, 2026 by the Reverse Age Lab evidence engine, from human studies, real reviews and our biohacker panel. How we grade. Is this medical advice? No. Rala organizes the published evidence; go over any change with your doctor, especially if you take meds.
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