Kirkland Signature Fiber Capsules Review

Kirkland Signature Psyllium Fiber, 720 Capsules is a Costco Kirkland Signature fiber supplement sold under item number 598848. The page describes the product as 100% natural psyllium husk fiber and lists the package as two bottles with 360 capsules each, for 720 capsules in total. Per the page, this item is only available for purchase at a local Costco warehouse and is not available for purchase on Costco.com. The warehouse listed on the page is Norfolk, where the item is shown as in stock, with a warehouse price of $19.99. The page also notes Same-Day Delivery through Instacart with pricing that may vary, and an in-stock notice for the selected warehouse. A price update note is shown alongside the $19.99 price, and the page lists a unit price of $0.03 per capsule. The Specifications section identifies the brand as Kirkland Signature, the form as Capsule, and the type as Fiber. The features section marks the item as FSA Eligible. The page includes an FSA explanation stating that a Flexible Spending Account allows employees to set aside pre-tax funds for medical expenses, that the item is marked as FSA eligible to show it may be purchased with an FSA, and that individual employers determine which expenses their FSA programs cover. It also lists categories of over-the-counter medical supplies that may be reimbursable, including contact lens solution, diagnostic devices such as blood pressure and blood glucose monitors, durable medical equipment and goods, insulin, and meds. The page shows an overall rating of 3.4 from 24 reviews, with a rating snapshot that lists 14 five-star reviews, one two-star review, and nine one-star reviews. The page does not print a full ingredient panel, suggested serving size, or servings per day in the text provided, so those details should be checked on the physical bottle or at the warehouse. The product description on this page is brief and focuses on sourcing, pricing, and FSA eligibility rather than detailed usage instructions.

Product Focus: Regularity: Long-Term ReliefAlso covers:Digestion
Tier ⓘ
Tier 4 · Rank 5
Tier 4 · Emerging. A promising mechanism or animal data, with thin human evidence so far. Rank 5 within Tier 4 for Regularity: Long-Term Relief; 7 of 15 overall. Tiers run from 1, the strongest evidence, to 5. How we grade →
Evidence ⓘ
63 /100
How strongly the evidence says this product works: human studies count most, then real reviews, then our biohacker panel.
Positive Reviews
93% of 7,503
Biohacker Mentions
10 of 10

Study, Trial or Testing Result Summary

Members Only53 human studies · 14 improved

4 of these 53 human studies gave the ingredient by drip, not by mouth.

53 human studies14 improved29 no effect117,796 people studied

This product is a fiber capsule, but no study of its main fiber ingredient was provided, so the research here covers only the small amounts of iron and potassium on the label. Iron does not help regularity and often causes constipation. Large reviews of women after childbirth found iron taken by mouth raised constipation compared with iron given into a vein [1][2]. In adults with kidney disease, ferric citrate caused more constipation than placebo [3][4]. In pregnant women, 80 milligrams of iron daily raised constipation and laxative use, while lower doses did not change digestive complaints [5]. A large study of veterans linked iron pills to more laxative use [6]. This product gives only about 1.2 milligrams of iron a day, far below the doses in these trials, so these findings say little about this capsule either way. For potassium, no study tested it for regularity; one study of a kidney salt-wasting disorder did not report whether constipation improved [7], and another did not give potassium at all [8]. Overall, the studies given neither show this fiber product works nor that it fails. Animal and cell studies are never counted.

See all 53 studies →Hide the studies

Review Totals and Summary

Members Only7,503 reviews · 93% positive
7,503 reviews · Amazon 7,346 · Walmart 73 · EBay 60 · Costco 24
93% positive4% neutral3% negative

Across the stores that sell it, Kirkland Signature Fiber Capsules carries about 7,430 ratings, and feedback leans positive, with roughly two in three star ratings at 4 or 5. Buyers like the convenience and price, while a vocal minority object to an ingredient change, and some Walmart-sold listings had a shipping problem. I left out reviews of the powder and other forms and cover the capsules only. **What buyers say it did for them:** Most praise is for simple, reliable fiber. One buyer says it is an "easy way to add fiber," and another reports being "very happy with the results." The eBay page adds that buyers say it works as well as Metamucil or better, and one says it helps with digestion and cholesterol. One recent eBay buyer, a week in, could not yet tell how well it worked. **What they complain about:** The biggest complaint is the ingredient list. One reviewer says it is "No longer pure" and cites emulsifiers, including polysorbate-80. Another asks Costco to "bring back the previous formula." Others dispute this: one says the company "made changes taking it back" to psyllium husk and gelatin only, and another buyer reports seeing only those two ingredients. The reviews conflict, so check the label on the package you receive. One reviewer links the product to a histamine sensitivity with swelling in the hands, and says similar products from other brands caused no trouble. That is a single report. On Walmart, several buyers of a two-pack received only one container: "only one container received instead of 2." One said customer service was helpful, and another got a refund. Availability is a smaller issue, as one Costco reviewer could not find the capsules in store after shelves were reduced. **Taste, smell, pill size or form:** The capsule form is the main draw. Reviewers switched from mixing powder because capsules are "much more convenient" and easier to take daily. The eBay page adds that one buyer dislikes chewing or drinking liquid fiber. One reviewer who bought the powder by mistake called it "very time consuming." The store summaries and reviews offer no detail on capsule size or smell. One Walmart reviewer mentions a sugar-free orange taste, which seems to refer to the powder. A reviewer who takes them notes you "must take with water or you can choke." **Value for money:** Price is a consistent strength. Reviewers call it "such a good deal compared to the name brand" and say Walmart/Kirkland "had the best price" against other store brands. The Costco summary describes the price as good and quality high. On eBay, buyers praise value for the quantity, say the capsules last a long time, and one finds more product in the bottle than Metamucil. **Who it seems to suit and who it did not:** It suits people who want daily fiber without mixing powder, and price-conscious buyers moving off name brands. Some take one capsule three times a day, others two or three before meals, and one takes five daily. It suited people less if they want to avoid additives such as emulsifiers, if they are sensitive to the product (as the histamine reviewer was), or if they order a multipack from the Walmart third-party seller and risk getting one container.

Biohacker Summary

Members Only10 of 10 recommend it
10 of 10 biohackers on our panel recommend it

On iron, the main ingredient, the panel leans toward testing first and supplementing only when levels are low. Four of the ten recommend it in their latest position, mainly for women who are deficient, for muscle, brain and hair health, and for thyroid function, while one takes it and finds less soreness in training. One panelist took 10 milligrams of heme iron and eventually stopped after years of low iron that no form of supplement fixed. Several warn against taking it blindly: one says too much iron promotes oxidative stress and inflammation, another says it should not be taken aggressively without proper testing, and another says low hemoglobin does not always mean low iron. Potassium is a smaller ingredient in this product, and the panel mostly talks about it as an electrolyte for blood pressure, muscle and heart function, with several using electrolyte drinks that contain it.

See all 10 biohackers →Hide the biohackers
  • Dr. Eric Berg · Iron · neutral
    • 30 Oct 2026 · neutral · YouTube ↗
      Identifies iron as the Achilles' heel of cancer, as it is needed for its DNA to replicate.
    • 29 Oct 2026 · Potassium · recommends · Podcast ↗
      States that people need more potassium than any other mineral, yet most people aren’t getting enough.
    • 28 Oct 2026 · Potassium · recommends · YouTube ↗
      Explains that potassium is essential for peristalsis, the pumping action through the colon, and without it, things can sit there, leading to constipation.
    • 25 Oct 2026 · Potassium · neutral · YouTube ↗
      Explains that the normal requirements for potassium are 4,700 mg every single day, and that very few people get half of that amount. They describe potassium's role in the sodium potassium pump, which is essential for cellular electricity, muscle contraction, and heart function. Deficiency can lead to tiredness, muscle cramps, heart palpitations, or rising blood pressure.
    • 25 Oct 2026 · Potassium · recommends · X ↗
      Recommends increasing potassium to restore balance and support healthy blood pressure.
    • 23 Oct 2026 · Potassium · recommends · YouTube ↗
      States that potassium is the most important electrolyte and that most people are not getting enough of it, needing around 4,700 mg daily, or even more, to avoid issues like fatigue, muscle cramps, heart palpitations, high blood pressure, and fluid retention.
    • 23 Oct 2026 · Potassium · neutral · Instagram ↗
      Dr. Eric Berg states that potassium is essential for health, supporting healthy muscles, nerves, and heart function, but warns that getting too much, especially from supplements, can be dangerous.
    • 23 Oct 2026 · Potassium · recommends · Instagram ↗
      Dr. Eric Berg states that most people are getting nowhere near enough potassium to balance the amount of sodium they’re already eating, implying a recommendation for increased potassium intake.
    • 20 Oct 2026 · Potassium · neutral · YouTube ↗
      Explains that potassium relaxes blood vessels, keeps elasticity in arteries, lowers adrenaline, supports the sympathetic nervous system, protects the endothelial layer of arteries, increases nitric oxide, and keeps insulin receptors sensitive.
    • 19 Oct 2026 · Potassium · uses · YouTube ↗
      Was very successful in practice using potassium for hypertension, noting that bodies need 4700 mg of potassium every single day.
    • 19 Oct 2026 · Potassium · neutral · YouTube ↗
      States that low potassium can lead to constipation because potassium controls the smooth muscles of the body, affecting the contraction and relaxation of muscles in the colon.
    • 18 Oct 2026 · neutral · YouTube ↗
      Mentions that grass-fed liver has heme iron, the most bioavailable form of iron that prevents anemia.
    • 10 Oct 2026 · warns · Podcast ↗
      Dr. Berg warns that too much iron can be damaging to the body and advises focusing on food sources to avoid overconsumption.
    • 3 Oct 2026 · warns · YouTube ↗
      Warns that too much iron, especially the ferrous sulfate or fumarate type found in many supplements, is corrosive and oxidizing, can mess with the liver, and create inflammation, noting that males have no natural way to excrete excess iron.
  • Dr. Mark Hyman · Iron · neutral
    • 21 Oct 2026 · neutral · YouTube ↗
      Mentions iron as an existing biomarker that plays a role in mental health, which Function Health includes in their measurements.
    • 16 Oct 2026 · Potassium · warns · Facebook ↗
      Warns that potassium bromate, a dough conditioner banned in the EU, UK, and Canada, is still allowed in U.S. bread.
    • 31 Aug 2026 · neutral · YouTube ↗
      Notes that a woman patient had very low iron.
    • 20 Aug 2026 · recommends · YouTube ↗
      States that they get the whole picture when it comes to iron, looking at ferritin, iron reserves, iron in the blood, iron saturation, and iron binding capacity to spot problems before full-blown anemia.
    • 20 Aug 2026 · Potassium · neutral · YouTube ↗
      States that potassium plays a critical role in nerve signaling and muscle contraction, especially in the heart, and low levels can lead to dangerous irregular heart rhythms.
    • 28 Jul 2026 · Potassium · neutral · Facebook ↗
      Notes that meds flush out potassium.
    • 17 Jun 2026 · Potassium · recommends · TikTok ↗
      States that with potassium, water can fully cross the cell membrane and get inside where it's needed for intracellular hydration.
    • 10 Jun 2026 · neutral · YouTube ↗
      Mentions iron as an example of a common nutritional deficiency.
    • 3 Jun 2026 · neutral · YouTube ↗
      Notes that many Americans are deficient in iron, which affects mood and brain function.
    • 18 May 2026 · recommends · Instagram ↗
      Recommends testing Iron as a biomarker before training for fitness.
    • 18 May 2026 · Potassium · recommends · YouTube ↗
      Recommends using targeted electrolyte support, advising to look for products with meaningful amounts of sodium, potassium, and magnesium, low sugar content, and avoidance of artificial colors, flavors, and sweeteners.
    • 12 May 2026 · Potassium · warns · Facebook ↗
      Warns that potassium bromate, a chemical dough conditioner, has been linked to cancer, oxidative stress, DNA damage, and reproductive harm in animal studies.
    • 24 Apr 2026 · neutral · YouTube ↗
      States that low iron, specifically a ferritin level less than 45, is a big hidden cause of insomnia, affecting up to half the population.
    • 26 Jan 2026 · Potassium · warns · Facebook ↗
      Warns that electrolyte drinks, while marketed for hydration, are loaded with high-glycemic sugars, synthetic potassium salts, and artificial dyes that can trigger insulin resistance, blood sugar crashes, and inflammation.
  • Siim Land · Iron · neutral
    • 14 Oct 2026 · neutral · Instagram ↗
      Mentions that iron is a mineral necessary for making collagen.
    • 30 Sep 2026 · Potassium · neutral · X ↗
      Lists potatoes and fruit as sources of Potassium.
    • 3 Sep 2026 · warns · YouTube ↗
      States that excess iron promotes oxidative stress and inflammation, which increases heart disease risk.
    • 31 Jul 2026 · Potassium · neutral · X ↗
      Notes that bananas have potassium but there are at least 8 other foods with more potassium than bananas.
    • 31 Jul 2026 · Potassium · neutral · X ↗
      States that potassium is the most abundant intracellular cation that helps to maintain intracellular fluid volume and that without it, one greatly increases the risk of hypertension, cardiovascular disease, diabetes, and stroke.
    • 24 Mar 2026 · neutral · YouTube ↗
      Notes that iron deficiency is found in children with premature graying of hair and that some people get gray hair due to iron deficiency.
    • 8 Feb 2026 · recommends · YouTube ↗
      Recommends ensuring sufficient iron intake, especially during pregnancy and early life, to prevent mental developmental and cognitive issues.
    • 5 Jan 2026 · neutral · YouTube ↗
      States his iron level is 103 micrograms per deciliter, which he considers a good result, and advises that men should aim for lower iron levels to reduce the risk of heart disease and aging.
    • 28 Dec 2025 · warns · YouTube ↗
      Places iron in the 'junk tier', warning that high iron levels are associated with heart disease, mortality, and liver disease, and advises caution with supplementation, especially for men with high iron.
    • 3 Dec 2025 · warns · YouTube ↗
      Warns that high iron levels are associated with increased risk of mortality and reduced lifespan, and that iron in excess is bad for maximum longevity. He states that iron levels slightly on the lower end, around 60 to 90 micrograms per deciliter, are associated with the lowest mortality risk, and that iron below 45 and above 145 micrograms per deciliter is associated with increased risk of mortality.
    • 20 Sep 2025 · warns · YouTube ↗
      Warns that very high iron levels can cause damage to the endothelium and increase the risk of heart disease, especially in men who accumulate iron more easily.
    • 8 Sep 2025 · warns · TikTok ↗
      Warns that too much iron can damage blood vessels, though people with low iron status are safe.
    • 29 Aug 2025 · Potassium · neutral · YouTube ↗
      States that potassium lowers blood pressure.
    • 23 Aug 2025 · warns · YouTube ↗
      Theorizes that Brian's lower iron status and hemoglobin status, possibly due to his plant-based diet and lack of iron supplementation, limits his V2 max.
  • Thomas DeLauer · Iron · neutral
    • 18 Sep 2026 · neutral · Facebook ↗
      Compares iron content in spinach (2.7mg) and beef (2.6mg), but emphasizes that beef's heme iron absorbs at about 25%, while spinach's non-heme iron absorbs at 2-8%.
    • 28 Oct 2026 · Potassium · uses · YouTube ↗
      Uses Element's cans which contain 100 milligram potassium, finding that electrolytes help his workout performance.
    • 24 Oct 2026 · Potassium · uses · YouTube ↗
      Uses Element's 100 mg potassium cans first thing in the morning to prime his day and help with workout performance.
    • 29 Aug 2026 · Potassium · recommends · YouTube ↗
      Recommends Element's ready-to-drink sparkling electrolyte drinks as a low or zero-calorie soda replacement that provides 1,000 milligrams of sodium, 200 milligrams of potassium, and 60 milligrams of magnesium.
    • 29 Aug 2026 · Potassium · uses · YouTube ↗
      Uses Element Electrolytes for about eight years, noting they contain 1000 mg sodium, 200 mg potassium, and 60 mg magnesium, and help curb appetite without adding many calories.
    • 24 Aug 2026 · recommends · YouTube ↗
      Recommends iron from meat, specifically red meat and beef liver, stating that it is a crucial part of the mechanistic triad for thyroid hormone function and is iron-dependent for iodine incorporation into thyroid hormone.
    • 8 Aug 2026 · Potassium · uses · YouTube ↗
      Personally drinks Element's pink lemonade or sparkling drinks, which contain 1,000 mg sodium, 200 potassium, and 60 magnesium, to hydrate and feel satiated, curbing hunger without stopping the ghrelin response.
    • 30 Jul 2026 · Potassium · uses · Instagram ↗
      Sometimes pivots to straight potassium supplementation when generally depleted.
    • 30 Jul 2026 · Potassium · uses · YouTube ↗
      Uses Element ready-to-drinks as a perfect electrolyte blend to start his day, noting that they contain 500 mg of sodium, 100 mg of potassium, and 30 mg of magnesium, and are slightly carbonated.
    • 18 Jul 2026 · Potassium · neutral · YouTube ↗
      Mentions potassium as an important electrolyte but suggests there's another layer to performance beyond just focusing on it.
    • 26 Jun 2026 · Potassium · recommends · YouTube ↗
      States that potassium is important for hydration, skin repair, and fluid balance in the skin, and recommends countering sodium intake with potassium.
    • 25 Jun 2026 · Potassium · uses · YouTube ↗
      Sips on LMNT Recharge cans throughout the day, especially when fasting, noting they are a new smaller can with 500 mg sodium, 100 mg potassium, and 30 mg magnesium.
    • 6 Jun 2026 · neutral · YouTube ↗
      Notes that iron is essential for delivering oxygen to muscles and the brain, making it an important cofactor for signals to reach their targets.
    • 4 Jun 2026 · recommends · YouTube ↗
      Recommends assessing iron along with selenium and iodine for optimal thyroid function, suggesting red meat as a source of iron.
  • Andrew Huberman · Iron · recommends
    • 20 Jul 2026 · recommends · YouTube ↗
      States that Iron is one of the critical nutrients with the best evidence for cognitive function and reducing the risk of dementia.
    • 27 Jul 2026 · Potassium · uses · YouTube ↗
      Uses Element, an electrolyte drink with sodium, magnesium, and potassium in correct ratios and no sugar, to ensure adequate hydration and electrolytes, especially when starting days fast or during physical exercise.
    • 18 May 2026 · Potassium · uses · YouTube ↗
      Uses Element, which contains potassium in the correct ratios, to ensure proper hydration and electrolyte intake for brain and body function.
    • 26 Mar 2026 · Potassium · neutral · Podcast ↗
      Mentions potassium as an electrolyte.
    • 12 Jan 2026 · Potassium · uses · YouTube ↗
      Uses Element, an electrolyte drink with sodium, magnesium, and potassium in correct ratios and no sugar, to ensure adequate hydration and electrolytes, drinking it first thing in the morning and during physical exercise.
    • 22 Dec 2025 · Potassium · uses · YouTube ↗
      Uses Element, an electrolyte drink with sodium, magnesium, and potassium in correct ratios and no sugar, to ensure he is hydrated and has sufficient electrolytes. He drinks it first thing in the morning and during physical exercise, especially on hot days.
    • 10 Nov 2025 · Potassium · uses · YouTube ↗
      Uses Element, an electrolyte drink with sodium, magnesium, and potassium but no sugar, to ensure adequate hydration and electrolytes, especially when waking up and during exercise.
    • 30 Oct 2025 · warns · YouTube ↗
      Warns that excess iron will increase the number of senescent cells in the body, which accumulate as people get older and cause inflammation and cancer. He notes that people who are healthy and have a fairly vegetarian diet often have slightly low iron levels but super amounts of energy.
    • 27 Oct 2025 · Potassium · uses · YouTube ↗
      Uses LMNT, an electrolyte drink with sodium, magnesium, and potassium in correct ratios and no sugar, to ensure adequate hydration and electrolytes for brain and body function, especially when starting his day fast or during physical exercise.
    • 25 Aug 2025 · Potassium · uses · YouTube ↗
      Uses Element, which contains potassium, for proper hydration and electrolyte balance.
    • 9 Jun 2025 · Potassium · uses · YouTube ↗
      Ensures adequate intake of sodium, magnesium, and potassium, which are vital electrolytes for the functioning of all body cells, especially neurons, by drinking Element.
    • 26 May 2025 · Potassium · uses · YouTube ↗
      Uses Element, an electrolyte drink with sodium, magnesium, and potassium, to ensure adequate hydration and electrolytes for optimal brain and body function, especially when waking up and during physical exercise.
    • 14 Apr 2025 · neutral · YouTube ↗
      Notes that about 50% of the population is iron deficient.
    • 31 Mar 2025 · neutral · Instagram ↗
      Mentions that the podcast will review the role of iron in treating depression.
  • Ben Greenfield · Iron · recommends
    • 9 Jul 2026 · recommends · YouTube ↗
      Recommends testing for and replenishing iron if levels are low, as it can affect the ability to maintain or preserve muscle, especially for those on GLP-1s.
    • 22 Oct 2026 · Potassium · uses · YouTube ↗
      Says he is drinking LMNT, which contains sodium, potassium, and magnesium, and states that he actually drinks this stuff.
    • 17 Aug 2026 · Potassium · recommends · Instagram ↗
      Recommends Celtic Sea Salt's new electrolyte drink 'Hydrate' for replenishing electrolytes and trace minerals lost through sweat, noting it contains 70 naturally occurring trace minerals, magnesium, taurine, and potassium, with no added sugar, artificial colors, or synthetic ingredients.
    • 29 May 2026 · neutral · Facebook ↗
      Notes that one can eat iron-rich foods or supplement with iron, but still feel exhausted if iron is not the missing piece, emphasizing that focusing on a single mineral in isolation can support a number on a lab test rather than the system itself.
    • 6 May 2026 · neutral · X ↗
      Mentions iron as a common deficiency.
    • 16 Apr 2026 · recommends · YouTube ↗
      Recommends a nutritious diet including iron, as it is critical for brain development.
    • 7 Jan 2026 · recommends · YouTube ↗
      Notes that the guidelines mention iron supplementation for infancy and early childhood.
    • 26 Nov 2025 · uses · Facebook ↗
      Started thinking about getting more heme-based iron in his diet after a podcast about reasons people feel fatigue.
    • 22 Nov 2025 · stopped · YouTube ↗
      Warns that modern society has flipped the narrative on iron intake, leading people to consume excessive amounts (20-50 mg) through an iron-fortified diet, which the body cannot assimilate, leading to storage in tissues and disrupting iron physiology, contributing to aging.
    • 10 Jul 2025 · Potassium · recommends · YouTube ↗
      Recommends adding potassium sulfate to a Morasco cold plunge.
    • 19 Apr 2025 · recommends · YouTube ↗
      Notes that some people need to supplement with iron, recommending iron biscinate as a form that doesn't irritate the gut.
    • 10 Apr 2025 · Potassium · neutral · YouTube ↗
      Mentions that potassium can be helpful for blood pressure but also risky for people with kidney disease or other conditions prone to elevated potassium levels, advising consultation with a physician.
    • 3 Apr 2025 · warns · YouTube ↗
      Explains that 10X can pinpoint genetic variations that predispose some people to absorbing too much iron and will adjust the iron content in their supplement, potentially reducing or removing it entirely.
    • 26 Dec 2024 · neutral · TikTok ↗
      Covers iron as a key supplement for kids.
  • Bryan Johnson · Iron · stopped
    • 8 Jul 2026 · stopped · YouTube ↗
      Has had low iron for 11 years and despite eating meat and trying all forms of iron supplementation at different times and sequences, none of it worked to raise his iron or ferritin levels.
    • 7 Jul 2026 · uses · X ↗
      Had low iron for 11 years, with ferritin averaging 38 ng/mL, and has finally boosted it back to healthy levels.
    • 26 Sep 2023 · uses · YouTube ↗
      Takes 10 milligrams of heme iron to get his iron levels up, as they are borderline.
    • Date not recorded · recommends · Website ↗
      Recommends adequate Iron for hair health, noting it is in the Blueprint stack.
    • Date not recorded · recommends · Source ↗
      Recommends supplementing with iron for brain health for both the mother and the baby during pregnancy.
    • Date not recorded · Potassium · recommends · Website ↗
      Recommends potassium during the luteal phase to help reduce water retention and bloating.
  • Dave Asprey · Iron · warns
    • 24 Jun 2026 · warns · X ↗
      Warns that if a doctor diagnoses anemia, one should not assume they just need more iron, as low hemoglobin doesn't always mean low iron and the issue can sometimes be how well the body is using iron.
    • 16 Jun 2026 · neutral · Facebook ↗
      Notes that when energy intake is too low for training demand, nutrient intake often falls short, especially for iron, which is associated with impaired recovery.
    • 19 Mar 2026 · recommends · YouTube ↗
      Recommends ensuring iron levels are good as it is a cofactor that can help thyroid function, especially with conversion issues.
    • 7 Feb 2026 · Potassium · recommends · YouTube ↗
      Recommends having more potassium during a fast to increase mineral intake.
    • 6 Jan 2026 · Potassium · recommends · YouTube ↗
      States that people who are salt-sensitive hypertensives usually need more potassium.
    • 1 Jan 2026 · Potassium · neutral · Podcast ↗
      Explains why electrolytes, especially sodium, potassium, and magnesium, are foundational for recovery.
    • 1 Jan 2026 · Potassium · recommends · YouTube ↗
      States that potassium is a really important electrolyte for everyone, but the demand is significantly higher for people with nervous system, immune system, and endocrine system dysregulation.
    • 30 Dec 2025 · Potassium · recommends · YouTube ↗
      Recommends using potassium citrate, if tolerated, to raise urinary citrate and block crystal formation.
    • 4 Dec 2025 · Potassium · neutral · YouTube ↗
      Notes that the potassium in the Vineia blood flow hydration product is from coconut water.
    • 26 Aug 2025 · Potassium · neutral · YouTube ↗
      Mentions that atrial fibrillation has to do with mineral status, including potassium.
    • 15 Aug 2025 · recommends · YouTube ↗
      Egg yolks, particularly raw egg yolks, fatty cuts of meat, choline sources like that, making sure there's enough iron and a lot of the micro minerals, trace minerals, things like that. Those would be really important for bone marrow because mineral deficiencies are going to block that at the start.
    • 7 Aug 2025 · Potassium · uses · YouTube ↗
      Takes a lot of potassium.
    • 5 Aug 2025 · Potassium · recommends · YouTube ↗
      Recommends lots of potassium citrate to help remove oxalates from the body.
    • 26 Jun 2025 · Potassium · uses · YouTube ↗
      Dave Asprey, who is salt-sensitive, balances out sodium intake with potassium, taking potassium citrate capsules from Designs for Health and carrying them all the time.
  • Dr. Rhonda Patrick · Iron · uses
    • 4 May 2026 · uses · YouTube ↗
      Recently found out he needed to get on an iron supplement and noticed he gets less sore in his training after taking it.
    • 23 Jun 2026 · Potassium · recommends · Facebook ↗
      Recommends getting enough potassium, noting that most people get too much sodium and not enough potassium.
    • 22 Jan 2026 · recommends · YouTube ↗
      Advises that menstruating women should ensure they are getting enough iron.
    • 28 Apr 2025 · warns · YouTube ↗
      Warns that iron is not an innocuous supplement and should not be taken aggressively without proper testing, as it can be complicated and has significant downsides if levels are not understood.
    • 29 May 2024 · Potassium · recommends · YouTube ↗
      States that maintaining a high potassium intake is important for hypertension.
    • 25 Aug 2020 · recommends · YouTube ↗
      Dr. Patrick explains that breast milk is incredibly low in iron, and by six months, infants can develop iron deficiency anemia, so pediatricians recommend introducing iron-rich complementary foods at that time.
    • 5 Apr 2017 · warns · YouTube ↗
      Rhonda discusses Dr. Lithgow's work on how excess dietary iron affects protein homeostasis in worms, noting that increased iron levels in the diet accelerated aging and the accumulation of insoluble proteins.
    • 11 Feb 2015 · Potassium · recommends · YouTube ↗
      Recommends getting enough potassium from veggies, bananas, and fruit because the body cares about the sodium-potassium ratio.
    • 6 Jan 2015 · Potassium · uses · YouTube ↗
      Dr. Patrick states that her smoothie, containing avocado and banana, has around 5,800 milligrams of potassium, which meets the adequate intake requirement for maintaining normal blood pressure and decreasing the risk of kidney stones.
    • Date not recorded · uses · Website ↗
      Dr. Patrick takes some iron during menstruation.
    • Date not recorded · warns · Website ↗
      Increased iron levels in the brain worsen cognitive test performance by as much as 10% in older adults, a phenomenon linked to brain atrophy and decline in memory and attention.
    • Date not recorded · neutral · Website ↗
      Iron plays a central role in health across the lifespan. It forms the core of hemoglobin, the molecule in red blood cells...
    • Date not recorded · neutral · Website ↗
      The requirement for iron is 1.8 times higher for vegetarians.
    • Date not recorded · recommends · Website ↗
      The findings highlight the importance of proper nutrition during development and suggest that iron supplementation may be beneficial, especially during adolescence.
  • Peter Attia · Iron · recommends
    • 8 Jun 2025 · recommends · YouTube ↗
      Recommends iron supplements for women of reproductive age who are iron deficient.
    • 6 Sep 2026 · Potassium · recommends · YouTube ↗
      States there is some evidence that increasing dietary potassium through potassium-rich foods like bananas and potatoes, rather than supplements, can lower blood pressure.
    • 9 Sep 2024 · neutral · YouTube ↗
      Notes that deficiencies in certain vitamins and minerals, such as iron, can be a cause of hair loss in women.
    • 8 Apr 2024 · neutral · X ↗
      Delves into the crucial yet often overlooked topic of iron and iron deficiency.
    • 8 Apr 2024 · neutral · YouTube ↗
      Explains that humans consume about 10 to 20 milligrams of iron per day, absorbing roughly 10% of that, which is 1 to 2 milligrams per day, perfectly offsetting the 1 to 2 milligrams lost daily.
    • 8 Apr 2024 · recommends · Podcast ↗
      Peter emphasizes the importance of consuming an adequate amount of iron daily to prevent deficiency.
    • 26 Oct 2020 · Potassium · recommends · YouTube ↗
      Notes that evolutionary ancestors consumed much more potassium than modern humans and suggests adding it back to the diet, ideally through whole foods.
    • 23 Jan 2020 · neutral · YouTube ↗
      Speculates that lower iron levels in women due to their menstrual cycle may offer a protective benefit against heart disease, citing data that metabolically deranged men benefit from therapeutic phlebotomy.
    • 31 Dec 2019 · Potassium · uses · YouTube ↗
      Mentions taking magnesium and potassium in addition to salt for minerals and electrolytes.

RAL Summary

Members OnlyTier 4 for Regularity: Long-Term Relief

The ineffective grade rests on the trace iron in the label rather than on the fiber that makes up the product, and no study of that fiber was given, so the evidence is thin rather than negative. So it is graded Tier 4, as the studies disagree.

  • Emerging: not enough evidence to rank higher yet.

Where the evidence disagrees: 29 of the 53 human studies found no effect.

More Details

Members OnlyBody systems · Combine with · Possible side effects

Body systems: Digestive system

Combine with: For regularity, take psyllium with plenty of water (at least 8 oz per dose) and separate it from other supplements and medications by 1-2 hours. Good companions are magnesium citrate for gentle stool softening, probiotics (Lactobacillus and Bifidobacterium strains) for gut flora balance, and adequate daily hydration. If the user still wants muscle support, add separate products such as whey or plant protein, creatine monohydrate (3-5 g daily), vitamin D3, and omega-3 fatty acids, taken at a different time from the fiber to avoid reduced absorption.

Possible side effects: Iron at much higher doses than in this product raised constipation in studies. One reviewer reported swelling in the hands they linked to histamine sensitivity, and another warned the capsules must be taken with water to avoid choking.

Supplement Facts

Total Carbohydrates 3 g · Iron 0.4 mg · Potassium 30 mg
Supplement Facts
Serving Size 2-6 Capsule(s)
Servings Per Container 60
Amount Per Serving% Daily Value
Calories10
Total Carbohydrates3 g
Protein1 g
Iron0.4 mg
Potassium30 mg

Other ingredients: Psyllium, Gelatin, Polysorbate 80, Caramel color, Acacia, Black Iron Oxide.

Directions: Directions: Adults 12 years & over: 2-6 capsules for increasing daily fiber intake and 6 capsules for cholesterol-lowering program. Take this product with 8 oz of water (swallow 1 capsule at a time) up to 3 times daily. Children under 12 years: Consult a doctor New users: Start with 1 serving per day; gradually increase up to 3 servings per day as necessary. You may initially experience changes in bowel habits or minor bloating as your body adjusts to increased fiber intake. Notice: Take this product with at least 8 oz (a full glass) of liquid. Taking this product without enough liquid may cause choking. Do not take if you have difficulty swallowing.

Label source: NIH label database · Report a label change

Show entire label

More regularity: long-term relief products

Members OnlyThe highest ranked for the same goal

Read more

Our articles on this subject

Graded November 8, 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.