Nature Made TripleFlex With Vitamin D3 Review
Tier ⓘ
Tier 4 · Rank 11
Tier 4 · Emerging. A promising mechanism or animal data, with thin human evidence so far. Rank 11 within Tier 4 for Blood Sugar; 56 of 67 overall. Tiers run from 1, the strongest evidence, to 5. How we grade →
Evidence ⓘ
15 /100
How strongly the evidence says this product works: human studies count most, then real reviews, then our biohacker panel.
Biohacker Mentions
0 of 10
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Study, Trial or Testing Result Summary
Members Only56 human studies · 16 improved
2 of these 56 human studies gave the ingredient by drip, not by mouth.
56 human studies16 improved29 no effect328,557 people studied
Vitamin D is at a full dose here (2000 units a day) and has the most blood sugar research. In people with type 2 diabetes, two large pooled analyses found that vitamin D modestly lowered fasting blood sugar, the long-term blood sugar marker and insulin resistance, most in people who were low in vitamin D [1][2]. In adults with prediabetes, three trials found a 15% lower risk of developing diabetes over about 3 years [3]. In pregnant women it lowered the risk of pregnancy diabetes by about 36% [4]. However, a large 5-year trial of older adults taking this same 2000 unit dose found no significant drop in diabetes risk [5], and another pooled analysis in prediabetes found no change in fasting blood sugar [6]. The joint ingredients do not appear to help blood sugar. Glucosamine did not change blood sugar, insulin or the long-term marker in controlled trials [7][8][9], and a review found some studies showing worse insulin sensitivity in people already insulin resistant [10]. Chondroitin, tested only with glucosamine, showed no benefit [8], and glucose tolerance changes were a common side effect [11]. Methylsulfonylmethane alone did not change blood sugar [12][13]. Animal and cell studies are never counted.
See all 56 studies →Hide the studies
- Across 53 trials of 9,443 pregnant women, vitamin D supplements lowered the risk of gestational diabetes by about 36% and improved blood sugar, blood fat, inflammation and oxidative stress markers.Dietary supplementation for gestational diabetes prevention and management: a meta-analysis of randomized controlled tri…
- In 46 trials of 4,313 people with type 2 diabetes, vitamin D lowered HbA1c by 0.20 points, fasting glucose by 5 mg/dl and insulin resistance, most in people who were deficient and with high doses over a short time.What is the impact of vitamin D supplementation on glycemic control in people with type-2 diabetes: a systematic review …
- In 39 trials of 2,982 people with type 2 diabetes, vitamin D lowered fasting glucose, HbA1c by 0.30 points, insulin resistance and fasting insulin, especially with short-term high doses in deficient or overweight people.Efficacy of vitamin D supplementation on glycaemic control in type 2 diabetes: An updated systematic review and meta-ana…
- In 15 trials of 2,833 pregnant women, two trials of 219 women found no clear difference in gestational diabetes risk between vitamin D and placebo or no treatment, though the evidence was very low quality.Vitamin D supplementation for women during pregnancy.
- In 8 trials with 1,580 people with prediabetes, vitamin D did not change HbA1c, fasting glucose or insulin resistance versus placebo but improved the 2-hour glucose tolerance test result.Association between vitamin D and prediabetes: A PRISMA-compliant meta-analysis.
- A pooled analysis of Iranian studies found vitamin D improved fasting glucose, HbA1c and insulin resistance in people with type 2 diabetes, while gestational diabetes showed gains only in insulin resistance.The effects of vitamin D supplementation on indices of glycemic control in Iranian diabetics: A systematic review and me…
- In 27 trials in pregnant women, vitamin D above 2000 IU a day lowered the risk of gestational diabetes by 30%, but did not change preterm birth or birth weight, and lower doses were enough to reduce preeclampsia.Vitamin D supplementation higher than 2000 IU/day compared to lower dose on maternal-fetal outcome: Systematic review an…
- In three placebo-controlled trials of adults with prediabetes, vitamin D cut the risk of developing type 2 diabetes by 15% over about 3 years and made a return to normal blood sugar 30% more likely.Vitamin D and Risk for Type 2 Diabetes in People With Prediabetes : A Systematic Review and Meta-analysis of Individual …
- An analysis of 15 meta-analyses of trials in women with polycystic ovary syndrome found vitamin D lowered triglycerides, total and LDL cholesterol, but did not change HDL cholesterol, insulin or body mass index.Effect of vitamin D supplementation on lipid profile, and hormonal functions in polycystic ovary syndrome: An umbrella s…
- A network analysis in people with type 2 diabetes found vitamin D was best of the vitamins for lowering HbA1c, with 4,100 to 7,500 IU a day giving the biggest gain in insulin resistance.Network meta-analysis of the effects of combined exercise and vitamin intervention on insulin resistance and related ind…
- A review of 16 reviews covering 250,569 pregnant women found low vitamin D linked to more gestational diabetes, and supplementation in women who already had gestational diabetes reduced some complications in them and their babies.Effects of vitamin D in pregnancy on maternal and offspring health-related outcomes: An umbrella review of systematic re…
- A review of 8 cohort studies and 11 trials found higher vitamin D status linked to lower type 2 diabetes risk, but supplements did not change blood sugar in people with normal glucose or established diabetes, and improved insulin resistance in two trials of people with glucose intolerance.Vitamin D and type 2 diabetes: a systematic review.
- A systematic review of 76 studies found the evidence on vitamin D in pregnancy too inconsistent and low quality to support firm conclusions about maternal blood pressure or blood sugar outcomes.Vitamin D supplementation in pregnancy: a systematic review.
- A review of knee osteoarthritis treatments found glucosamine studies on blood sugar handling were short or excluded people with metabolic disorders, so no conclusion on blood sugar could be drawn.Treatment of primary and secondary osteoarthritis of the knee.
- A review of eleven studies found mixed evidence on glucosamine and blood sugar handling: four studies found worse insulin sensitivity or higher fasting glucose, especially in people who already had impaired glucose tolerance or insulin resistance.The effect of glucosamine on glucose metabolism in humans: a systematic review of the literature.
- A review of eleven observational studies found that reported lower rates of death and diseases including heart disease and diabetes with glucosamine use were likely due to selection bias, so they cannot support its use for prevention.Glucosamine and lower mortality and cancer incidence: Selection bias in the observational studies.
- In 22,220 older US adults followed for about 5.3 years, 2000 IU of vitamin D3 daily did not significantly reduce type 2 diabetes risk compared with placebo, though pooling with prior trials showed a modest reduction.Vitamin D supplementation vs. placebo and incident type 2 diabetes in an ancillary study of the randomized Vitamin D and…
- In the VITAL trial, baseline blood sugar markers predicted later type 2 diabetes and heart disease, and randomization to vitamin D did not change those associations.Biomarkers of glucose-insulin homeostasis and incident type 2 diabetes and cardiovascular disease: results from the Vita…
- In 627 people with knee osteoarthritis given glucosamine sulfate plus chondroitin or a reference product for 24 weeks, knee pain improved similarly, and changes in glucose tolerance were among the most frequent treatment-related side effects.Treatment of knee osteoarthritis with a new formulation of a fixed-dose combination of glucosamine sulfate and bovine ch…
- In 307 infertile men, taking 1400 units of vitamin D3 plus 500 mg calcium daily for 150 days lowered fasting insulin and insulin resistance and raised HDL cholesterol compared with placebo.Vitamin D Supplementation Improves Fasting Insulin Levels and HDL Cholesterol in Infertile Men.
- In 239 Italian adults with type 2 diabetes and low vitamin D, six months of vitamin D3 lowered fasting and after-meal glucose and HbA1c compared with placebo, and some patients needed less meds.Vitamin D3 supplementation improves glycemic control in type 2 diabetic patients: Results from an Italian clinical trial…
- In a 12-month placebo-controlled trial of 173 African-American men with prediabetes and low vitamin D, weekly high-dose vitamin D2 raised vitamin D levels but did not improve insulin sensitivity or HbA1c compared with placebo.EFFECT OF HIGH-DOSE VITAMIN D REPLETION ON GLYCEMIC CONTROL IN AFRICAN-AMERICAN MALES WITH PREDIABETES AND HYPOVITAMINOS…
- In 130 adults with type 2 diabetes on a med, vitamin D over 6 months improved HbA1c and lowered advanced oxidation protein products at 3 months with higher doses, but did not significantly change insulin resistance.The Effects of Vitamin D Supplementation on Metabolic and Oxidative Stress Markers in Patients With Type 2 Diabetes: A 6…
- In 100 adults with type 2 diabetes, drinking vitamin D-fortified yogurt twice daily for 12 weeks improved fasting glucose, HbA1c, insulin sensitivity index and blood fats compared with plain yogurt, along with markers of blood vessel lining health.Regular consumption of vitamin D-fortified yogurt drink (Doogh) improved endothelial biomarkers in subjects with type 2 …
- In 78 overweight or obese adults, taking 1,000 IU of vitamin D3 daily for 12 weeks, with or without magnesium, did not improve glucose, insulin or insulin resistance compared with placebo.Combined vitamin D and magnesium supplementation does not influence markers of bone turnover or glycemic control: A rand…
- In 60 people with spinal joint arthritis, taking a joint supplement sachet daily for 6 weeks relieved back pain about as well as meds, and blood glucose changes stayed within the upper limit of normal.[Experience of using the chondroprotector Sustagard Artro (sashe) in the treatment of lower back pain].
- In 20 lean and 20 obese adults, 1500 mg of glucosamine daily for 6 weeks did not cause or significantly worsen insulin resistance or blood vessel dysfunction compared with placebo.Oral glucosamine for 6 weeks at standard doses does not cause or worsen insulin resistance or endothelial dysfunction in…
- In 22 veterans with type 2 diabetes, a daily glycocalyx-precursor supplement containing glucosamine sulfate for 8 weeks did not improve blood vessel lining integrity or blood vessel function compared with placebo.Impact of dietary supplementation of glycocalyx precursors on vascular function in type 2 diabetes.
- In 22 overweight or obese adults, 3 g of methylsulfonylmethane daily for 16 weeks raised HDL cholesterol compared with the start, but the abstract reports no blood sugar benefit.The Effect of Daily Methylsulfonylmethane (MSM) Consumption on High-Density Lipoprotein Cholesterol in Healthy Overweigh…
- In 19 healthy adults, 1500 mg of glucosamine sulfate daily for 12 weeks did not change fasting or post-sugar-drink blood glucose, insulin, or long-term blood sugar compared with placebo.Effect of glucosamine supplementation on fasting and non-fasting plasma glucose and serum insulin concentrations in heal…
- In 18 healthy adults, glucosamine infused into the forearm artery for up to 5 hours did not change how well insulin moved sugar into the muscle or the body compared with saline.Short-term glucosamine infusion does not affect insulin sensitivity in humans.
- In 16 adults with type 2 diabetes and low vitamin D, 12 weeks of vitamin D3 (280 mcg daily for 2 weeks, then 140 mcg daily) raised vitamin D levels but did not improve insulin sensitivity or HbA1c compared with placebo; there were only borderline gains in insulin secretion.Effects of 12 weeks high dose vitamin D3 treatment on insulin sensitivity, beta cell function, and metabolic markers in …
- In 12 people with diabetes and low HDL cholesterol, 1,500 mg of glucosamine a day for 2 weeks did not change fasting blood sugar, fructosamine, HDL cholesterol or apolipoprotein AI compared with placebo.The effect of glucosamine on Serum HDL cholesterol and apolipoprotein AI levels in people with diabetes.
- In 10 healthy adults, short-term glucosamine infusion raised fasting blood sugar slightly, and at the high dose it lowered insulin and glucose action by about 30-40%.Effects of glucosamine infusion on insulin secretion and insulin action in humans.
- Over 24 months, 4000 IU of vitamin D3 daily did not improve insulin sensitivity or insulin-producing cell function in overweight adults with prediabetes overall, though people starting with very low vitamin D levels (below 12 ng/mL) showed a benefit.Effects of Vitamin D Supplementation on Insulin Sensitivity and Secretion in Prediabetes.
- In people with well-controlled type 2 diabetes, 1,500 mg of glucosamine with chondroitin daily for 90 days did not change long-term blood sugar (hemoglobin A1c) compared with placebo.The effect of glucosamine-chondroitin supplementation on glycosylated hemoglobin levels in patients with type 2 diabetes…
- In adults with back pain or osteoarthritis, 6 g of methylsulfonylmethane daily for 16 weeks did not change glucose, blood pressure, weight, or blood, liver or kidney tests compared with placebo.Methylsulfonylmethane for treatment of low back pain: A safety analysis of a randomized, controlled trial.
- In 140 pregnant women, a blend of inositol, zinc, vitamin C, folate and 100 mg daily methylsulfonylmethane taken from before pregnancy to week 24 was linked to better blood sugar tests and HbA1c than folic acid alone.Prevention of neural tube defects and maternal gestational diabetes through the inositol supplementation: preliminary re…
- In 100 Tunisian adults with type 2 diabetes and low vitamin D, three months of vitamin D supplementation raised vitamin D levels but did not significantly improve blood sugar control or insulin resistance.Influence of vitamin D supplementation on glycemic control in type 2 diabetics.
- In 83 pregnant women with high early fasting glucose, a blend including 10 mg daily methylsulfonylmethane led to gestational diabetes in 5 of 40 women versus 18 of 43 on folic acid alone.The influence of D-chiro-inositol and D-myo-inositol in pregnant women with glucose intolerance.
- In a small case-control study of 18 people with type 2 diabetes, lower vitamin D was linked to more microvascular complications such as nerve, eye, and kidney damage.Vitamin D levels and microvascular complications in type 2 diabetes.
- In 50 people with Cushing's disease who were low in vitamin D, a single large vitamin D3 dose followed by six weeks of treatment improved insulin sensitivity and raised vitamin D levels, compared with their own starting values.Vitamin D Deficiency in Cushing's Disease: Before and After Its Supplementation.
- A genetic analysis of over 10,000 people in China found no causal link between genetically higher vitamin D levels and type 2 diabetes, prediabetes, or blood sugar measures.Vitamin D, prediabetes and type 2 diabetes: bidirectional Mendelian randomization analysis.
- In a large survey of Hispanic and Latino adults without diabetes, those eating the most vitamin D from food had lower insulin resistance, but their two-hour blood sugar after a glucose drink was higher, and HbA1c showed no link.Vitamin D, Calcium, Magnesium, and Potassium Consumption and Markers of Glucose Metabolism in the Hispanic Community Hea…
- In a Chinese cohort of 5,543 adults followed for about 3.9 years, lower blood vitamin D was not linked to a higher risk of developing type 2 diabetes.25-Hydroxyvitamin D and Incidence of Type 2 Diabetes from a Chinese Cohort Study.
- In 2,160 people in Tehran, higher blood vitamin D levels were linked to lower insulin resistance and better blood sugar measures, though this study did not test supplements.The association of vitamin D levels and insulin resistance.
- In 912 people from western India, low vitamin D was not associated with HbA1c or insulin resistance in either people with type 2 diabetes or non-diabetic controls.Does vitamin D play a significant role in type 2 diabetes?
- In pregnant South African women, vitamin D levels did not change between visits, while some vitamin D metabolites were linked to blood sugar and insulin measures in mixed directions.Longitudinal changes in vitamin D and its metabolites in pregnant South Africans.
- In 235 people with type 2 diabetes, low vitamin D levels were not linked to diabetic eye damage or its severity.Is there any correlation between vitamin D insufficiency and diabetic retinopathy?
- In 234 young Indian military recruits, higher vitamin D was linked to lower fasting blood glucose, but not to insulin resistance, cholesterol, or triglycerides.Vitamin D, body mass composition and metabolic risk factors in healthy young Indians.
- In 227 obese Mexican children and adolescents, those with low vitamin D had higher fasting insulin and insulin resistance than those with sufficient levels.Vitamin D status and its relation to insulin resistance in a Mexican pediatric population.
- In 180 middle-aged adults, low vitamin D was linked to higher odds of type 2 diabetes, but higher vitamin D levels were also associated with higher blood sugar and insulin resistance measures, so the pattern was inconsistent.Association of vitamin D deficiency with insulin resistance in middle-aged type 2 diabetics.
- In 174 adults with prediabetes or normal glucose tolerance, higher levels of vitamin D binding protein were linked to nerve control of the heart and body fat, but this study did not test any vitamin D supplement.Vitamin D binding protein is related to cardiac autonomic function and metabolic status in prediabetes.
- In 127 women with recurrent pregnancy loss, vitamin D levels were not significantly linked to insulin levels or insulin resistance, although women with higher insulin resistance had lower vitamin D.Glucose/insulin metabolism and vitamin D in women with recurrent pregnancy loss.
- In rats fed a high-sugar diet, vitamin D3 lowered blood glucose and improved insulin release during a glucose load, and lab work suggests this works by calming inflammation in insulin-producing cells.Vitamin D protects against high glucose-induced pancreatic β-cell dysfunction via AMPK-NLRP3 inflammasome pathway.
- Genetic analyses suggested that people genetically predisposed to glucosamine use had lower odds of type 2 diabetes, but this is not a trial and cannot confirm that taking the supplement lowers diabetes risk.Glucosamine supplementation contributes to reducing the risk of type 2 diabetes: Evidence from Mendelian randomization c…
Review Totals and Summary
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Biohacker Summary
Members Only0 of 10 recommend it
0 of 10 biohackers on our panel recommend it
Vitamin D3, the main ingredient, gets broad support: all ten panelists spoke about it, and most recommend it or take it themselves, while two stay neutral and one of those still says most people are probably low and benefit from supplementing. People take it for immune health, brain and mood, bone strength, heart health, and to make up for little sun in fall and winter, and several say to test blood levels first, with targets ranging from about 40 up to 100 nanograms per milliliter. Doses vary widely, from 5000 international units a day, which three panelists take in the morning, to at least 10,000 a day from one who also warns that official intake guidance is too low. Several say to take it with dietary fat for better absorption, and others pair it with vitamin K2, magnesium, or both, especially for bones. The one caution is that one panelist says supplementing makes little sense for most goals unless you are actually deficient, and no one said they stopped taking it.
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Dr. Eric Berg · Vitamin D · warns
- Dr. Berg warns that the recommended daily intake for vitamin D is based on a massive error and that the actual necessary amount is closer to 8,895 IU, with millions remaining deficient.
- Recommends getting vitamin D levels tested to ensure they are between 50 and 70, as vitamin D is intimately involved in regulating prostate size.
- Recommends taking at least 10,000 IUs of vitamin D3 every single day in the winter, stating it is the most important vitamin to lower cancer risk.
- Recommends vitamin D to support the immune system, aiming for blood levels between 80 to 100 ng per ml.
- Recommends taking no less than 10,000 IU's of vitamin D3 for osteoporosis, alongside magnesium and K2.
- Recommends increasing vitamin D to restore balance and support healthy blood pressure.
- States that a lack of vitamin D can potentially cause achy bones or crashing mood.
- States that vitamin D is intimately involved in the immune system and recommends taking at least 10,000 IUs each day.
- States that taking high doses of vitamin D3 for 14 days can improve mood, sleep, low back pain, skin issues, and blood pressure, as well as act as a natural anti-inflammatory and reduce susceptibility to sickness.
- Mentions that grass-fed liver has vitamin D.
- Recommends glucosamine for osteoarthritis, noting it is a precursor for cartilage, increases lubrication and synovial fluid in joints, and helps prevent the breakdown of cartilage.
- Recommends N-Acetyl Glucosamine (NAG) as a precursor to the GAG structure, which can help improve psoriasis by controlling rapidly dividing cells, stimulating GAG production in the colon and skin, and providing an immunosuppressive and anti-inflammatory effect.
- Dr. Berg states that the breakdown of protein causing eye floaters can be eliminated with a remedy called liquid MSM, which stands for Methylsulfonylmethane.
- States that chondroitin sulfate is the most potent inhibitor of kidney stones and can reduce the risk of getting them.
Dave Asprey · Vitamin D · uses
- Takes Vitamin DAKE from Suppgrade Labs.
- Suggests that vitamin D supports brain health, muscle function, and focus.
- Host Dave Asprey explains why correcting a vitamin D deficiency still makes sense for male fertility, even though supplementation did not improve overall semen parameters in a randomized trial.
- States that currently, he is only taking vitamin C and vitamin D.
- Recommends vitamin D, noting it's actually a hormone and that most people are deficient, even those who take it, because they don't take enough.
- States that most people on the spectrum are low in vitamin D and need more of it, mentioning his own product, Vitam DAKNE, which contains real vitamin A.
- Dave Asprey recommends Vitamin D3 with K2, explaining D3 is a hormone made from sunlight and K2 directs calcium into bones, not arteries, highlighting its low cost, widespread deficiency, and the ability to test its effectiveness.
- Recommends Vitamin D as one of the most important supplements for overall health.
- Takes Vitamin DAKE from Suppgrade Labs because D3, A, K2, and E work together.
- Mentions taking vitamin D in the morning, comparing it to the daily dosing of testosterone.
- Implies chondroitin is ineffective for joint health, grouping it with glucosamine as 'age-old supplements for knees' that are 'just dead in 2025' and not fixing the problem.
- Notes that people dealing with osteoarthritis typically take high doses of glucosamine, MSM, and similar supplements, spending about $60-70 a month with virtually no benefit.
- Found that taking glucosamine HCL significantly improved his knee pain when he was younger.
- Recommends glucosamine HCL, not glucosamine sulfate, as an affordable old-school supplement for knee and joint pain, suggesting up to a gram.
Siim Land · Vitamin D · recommends
- Advises against taking vitamin D in the morning with other supplements because it is fat soluble and requires dietary fat for better absorption.
- Recommends taking Vitamin D with fat for better absorption.
- States that Vitamin D connects biology to light and that UVB reaching the skin enables its production.
- Thinks vitamin D has some of the strongest evidence and is worth considering.
- Notes that Vitamin K2 pairs well with vitamin D by regulating calcium and bone mineralization.
- Recommends taking vitamin D supplements with some fat to maximize its absorption, suggesting with food or a teaspoon of olive oil.
- Notes that taking vitamin D3 with a fat-containing meal resulted in 32% higher peak blood vitamin D levels.
- Recommends taking Vitamin D in the morning or at lunch with fat.
- Notes that Boron improves vitamin D.
- Recommends Vitamin D because microglia contain Vitamin D receptors, and Vitamin D helps keep the immune system properly regulated, with low levels associated with greater neuroinflammation and a higher risk of autoimmune conditions.
- States that glucosamine does actually improve joint pain, despite some thinking it's a scam supplement.
- Notes that glucosamine, often considered a gimmick for joint health, may also be beneficial for skin anti-aging due to its sulfur content supporting glutathione production and inhibiting MMPs.
- Explains that while there are no human studies on chondroitin for skin anti-aging, cell studies suggest it stimulates procollagen expression and promotes wound healing and skin regeneration.
- Notes that Glucosamine Sulfate is known for joint benefits, has anti-inflammatory effects, and even skin anti-aging effects, possibly through its sulfur content aiding glutathione synthesis, rating it as 'good' but not 'god tier'.
Ben Greenfield · Vitamin D · recommends
- Notes that Vitamin D is actually a hormone and recommends patients aim for levels around 40 to 50, or even 60 for fracture healing, for optimal healing, as opposed to just above 20 which is considered normal.
- Mentions vitamin D as part of a bare-minimum protocol.
- Advises getting vitamin D levels between 60 and 100 nanograms per milliliter as a minimum step for overall health and to slow down heart disease.
- Has been taking Vitamin D3 K2 for over a decade.
- Notes that sunlight influences more than just vitamin D production.
- Recommends keeping vitamin D levels high, suggesting that a supplement is probably not a bad idea, especially given that many people are deficient due to spending most of their time indoors.
- Recommends getting enough vitamin D for blood pressure management.
- Recommends optimizing vitamin D levels to a serum score of around 50 to 80 nanograms per milliliter, as deficiency is linked to tinnitus volume and can assist with it.
- Recommends using hormone building blocks like vitamin D for hormone optimization.
- Notes that vitamin D deficiency is the most common deficiency.
- Does not personally take D-glucosamine but plans to research its dosage and sourcing after seeing data suggesting it mimics calorie restriction and extends lifespan.
- Mentions glucosamine sulfate as an ingredient in the NOVOS supplement, which has decent human research for cellular longevity and staving off DNA damage.
- Ben Greenfield recommends glucosamine as a natural compound that supports recovery and joint comfort.
- Ben Greenfield recommends chondroitin as a natural compound that supports recovery and joint comfort.
Dr. Mark Hyman · Vitamin D · recommends
- Recommends Vitamin D for health, stating that amazing things happen when patients' vitamin D statuses reach optimal levels.
- Mentions vitamin D as an existing biomarker that plays a role in mental health, which Function Health includes in their measurements.
- Notes that vitamin D plays a role in immune function.
- Recommends checking vitamin D levels and states that if they had to pick one single intervention for immune health, vitamin D would be it.
- Dr. Hyman discusses vitamin D in relation to sun exposure patterns.
- States that vitamin D supplementation can help with oxidative stress.
- Mentions vitamin D as a key nutrient for supporting immune function.
- States that vitamin D is probably the single most important intervention for immune health, recommending levels of 45 to 70 and emphasizing testing to determine the right dose.
- Notes that rickets, which causes terrible bone deformities, is caused by vitamin D deficiency.
- Notes that vitamin D is an important nutrient for brain performance and aging, and that many people have gaps in these nutrients.
- Uses N-acetylglucosamine (NAG), describing it as a safe, non-toxic compound derived from shrimp, to support the gut wall.
- Notes that glucosamine is found only in beef and a lack of it has been associated with harm to the body, including connective tissue dysfunction.
Thomas DeLauer · Vitamin D · uses
- Uses vitamin D3 in the fall and winter months when getting less sun, as it's important to supplement it then.
- Recommends taking a massive amount of vitamin D simultaneously with an early morning massive breakfast to help reset circadian rhythms and address hyperphagia.
- Recommends Vitamin D, stating that it has receptors throughout the brain and deficiency can quickly impact brain and mood.
- Takes supplemental vitamin D because he is skin sensitive and from northern latitudes, limiting his UV exposure.
- Recommends taking vitamin D on non-liver days to ensure both nutrients get proper receptor access.
- Takes Purity's liquid vitamin D3 with K2 because she is constantly inside during the day; D3 is for overall wellness and K2 helps the body absorb calcium properly.
- Recommends getting vitamin D, suggesting it can be obtained while walking.
- States that vitamin D is best obtained from the sun, but getting it from food definitely helps, and notes its role as a hormone influencing many cells.
- Recommends D3, suggesting a dose of 2000-4000 IU, and notes that MK-7 slowed bone loss over three years.
- Recommends vitamin D, especially for Hashimoto's, explaining that it drives T reg expansion to suppress autoimmune responses that attack the thyroid, and notes that vitamin D and selenium deficiencies often co-occur.
- Notes that glucosamine chondroitin used to be popular for joint pain, but the literature on its efficacy was weak.
- Notes that the literature for glucosamine and glucosamine chondroitin for joint pain was pretty weak in terms of efficacy.
- Has been taking glucosamine religiously since the 90s after meeting a jacked 63-year-old man who recommended it, leading to the creation of his own 'Joint Warfare' supplement which includes it.
- Has been taking chondroitin religiously since the 90s after meeting a jacked 63-year-old man who recommended it, leading to the creation of his own 'Joint Warfare' supplement which includes it.
Bryan Johnson · Vitamin D · uses
- Takes 5000 IU of Vitamin D3 in the morning for general health.
- Takes 5000 IU of Vitamin D3 in the morning for general health.
- Mentions that the sunlight assessment claims low vitamin D levels cause the immune system to misfire, and notes that their vitamin D has been measured.
- Takes 5000 IU of Vitamin D3 in the morning for longevity.
- He takes 5000 IU of Vitamin D3 in the morning for general health.
- Takes 5000 IU of Vitamin D3 in the morning for general health.
- Takes 5,000 IU of Vitamin D3 in the morning for longevity.
- Takes 5,000 IU of Vitamin D3 in the morning.
- Takes 5,000 IU of Vitamin D3 in the morning.
- He takes 5000 IU of Vitamin D3 in the morning for general health.
- Advises avoiding Glucosamine Sulfate during pregnancy.
- Bryan Johnson takes Glucosamine Sulfate KCI daily as part of his Longevity Mix, which supports cartilage, joints, & skin.
Dr. Rhonda Patrick · Vitamin D · neutral
- Vitamin D supplementation was linked to a 40% lower risk of dementia in an observational study of more than 12,000 older adults.
- Mentions that vitamin D also plays a role in maintaining muscle mass.
- Recommends ensuring adequate vitamin D intake for men's sperm health.
- Vitamin D and strength training alone did not, but adding them strengthened the effect on one clock, with the full combination slowing that measure by ~3.8 months.
- Lutein and zeaxanthin can also be obtained from certain multivitamins.
- Recommends Vitamin D, noting it regulates over 5% of the genome, including genes involved in immune defense, neurotransmitter synthesis, and longevity, and correcting deficiency may slow epigenetic aging.
- Uses Vitamin D3 as an example of a supplement that an AI model could track to see its impact on other metrics like glucose levels.
- Recommends Vitamin D, explaining that it regulates over 5% of the genome, including genes involved in immune defense, neurotransmitter synthesis, and longevity.
- Combining omega-3s with vitamin D and exercise has an additive effect, translating to ~3 months of slowed biological aging.
- The effect got stronger when omega-3 was combined with vitamin D and resistance training, with the full stack delaying phenotypic aging by about 3.8 months.
- States they don't use glucosamine chondroitin much and haven't looked into the database in many years, noting mixed evidence and that it wouldn't be their first, second, or third line of defense for consistent injury issues.
- Discusses whether glucosamine chondroitin actually helps joints.
- Considers glucosamine a 'tier two' supplement, noting that while the effect is small, there seems to be some evidence for its efficacy.
- Dr. Rhonda Patrick discusses glucosamine and Alzheimer's.
Andrew Huberman · Vitamin D · neutral
- Notes that most people are probably deficient in vitamin D and benefit from supplementing, but there's no point in doing it unless you're deficient for most things.
- Takes 5,000 IU of Vitamin D3 in the morning for longevity.
- Takes 5000 IU of Vitamin D3 in the morning for general health.
- States that Vitamin D is one of the critical nutrients with the best evidence for cognitive function and reducing the risk of dementia.
- Takes 5000 IU of Vitamin D3 in the morning.
- He takes 5,000 IU of Vitamin D3 in the morning for overall health.
- Takes 5000 IU of Vitamin D3 in the morning.
- Takes 5,000 IU of Vitamin D3 in the morning for general health.
- Takes 5000 IU of Vitamin D3 every day for longevity.
- Takes 5,000 IU of Vitamin D3 in the morning.
Peter Attia · Vitamin D · uses
- Lists vitamin D as one of her staple supplements.
- Notes that several studies show patients taking vitamin D can reduce TPO levels and prolong the honeymoon period of Hashimoto's disease.
- States that in mouse studies, there was a combined effect of alpha ketoglutarate with vitamin D for both sexes.
- Uses vitamin D as an example of how people might dismiss its efficacy due to failed clinical trials that didn't adjust the dose or measure levels.
- In mouse studies, Peter Attia's team found a combined effect of AKG with Vitamin D for both sexes.
- Suggests that supplementing with lots of vitamin D might help overcome the negative effects of phenytoin on bone health by improving calcium absorption, though he is unaware of studies on this.
- Recommends Vitamin D3 as one of the 'big three' micronutrients for bone health, suggesting a daily intake of 800 to 1,000 IU, which can be obtained through sunlight or supplementation.
- Suggests that supplementing with lots of vitamin D might overcome the negative effects of phenytoin on bone health by counteracting increased catabolism of vitamin D and subsequent decreased calcium absorption.
- Recommends vitamin D for people who tend to be vitamin D deficient, such as those living in Portland, Oregon.
- Discusses evaluating vitamin D, understanding deficiency, and optimal levels.
- Would make a smoothie with whey protein isolate, glutamine, glucosamine, and flaxseed oil for recovery after his run.
RAL Summary
Members OnlyTier 4 for Blood Sugar
Vitamin D at a full dose has modest but mixed support for blood sugar, while the other ingredients show no benefit, and there are no reviews, so the evidence stays emerging.
- Emerging: not enough evidence to rank higher yet.
Where the evidence disagrees: 29 of the 56 human studies found no effect.
More Details
Members OnlyBody systems · Combine with · Possible side effects
Body systems: Endocrine system, Metabolic system, Musculoskeletal system
Possible side effects: Glucosamine with chondroitin was linked to changes in glucose tolerance, and glucosamine may worsen insulin sensitivity in people already insulin resistant.
Supplement Facts
Vitamin D3 2000 IU · Glucosamine Hydrochloride 1.5 g · Chondroitin Sulfate 800 mg
Supplement Facts
Serving Size 2 Caplet(s)
Servings Per Container 40
Amount Per Serving% Daily Value
| Vitamin D3 | 2,000 IU | |
| Sodium | 75 mg | |
| Glucosamine Hydrochloride | 1.5 g | † |
| Chondroitin Sulfate | 800 mg | † |
| Methylsulfonylmethane | 750 mg | † |
† Daily Value not established.
Other ingredients: Glucosamine Hydrochloride, Sodium Chondroitin Sulfate, Methylsulfonylmethane, Hypromellose, Color added, Silicon Dioxide, Magnesium Stearate, Glyceryl Behenate, Polyethylene Glycol, Corn Starch, Triethyl Citrate, Polysorbate 80, Vitamin D3.
Directions: 2 caplets per day Suggested use: Take two caplets daily, with food. For easier swallowing, take with water before and during ingestion. Caplets can be taken together or at different times during the day. Take 4-6 weeks to see results.
Barcode (UPC) 031604011574 · Label source: NIH label database · Report a label change
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Graded November 6, 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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