Supplement analysis backed by scientific evidence · PT

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Limited evidenceJoints & skin

Hair-Skin-Nails Formulas

These formulas are built around megadose biotin, which does nothing for hair in people who are not deficient — and which reliably corrupts common blood tests, including the troponin assay used to diagnose heart attacks. The category's few positive trials are small, sponsor-funded, and specific to individual branded products.

What the science says

  • High-dose biotin thickens hair and strengthens nails Limited evidence

    A review of the published literature found every case of biotin improving hair or nails occurred in people with an underlying biotin deficiency or an inborn metabolic disorder — there is no evidence of benefit in healthy, non-deficient people. Biotin deficiency is rare, the adequate intake is about 30 mcg/day, and typical formulas contain 5,000-10,000 mcg, i.e. 150-350 times that amount with no added effect.

  • Multi-ingredient formulas regrow hair Limited evidence

    A 2023 systematic review in JAMA Dermatology assessed 30 studies of nutritional supplements for hair loss and concluded that while a handful of specific branded products showed benefit in small trials, the overall evidence base is low quality and heavily industry-funded, and does not support supplements generally. Findings for one branded formula do not transfer to a different product with a similar-looking label.

  • Correcting a deficiency helps — if you actually have one Moderate evidence

    Iron deficiency, zinc deficiency, hypothyroidism and protein malnutrition genuinely cause hair shedding, and correcting them restores growth. That is an argument for testing ferritin, TSH and zinc before buying a formula — not for taking a shotgun blend — and repletion doses (e.g. therapeutic iron for a ferritin under 30 ng/mL) are far higher than what these products contain.

  • Improves skin and nails visibly Limited evidence

    Most formulas include vitamin C, vitamin E, zinc, silica, MSM and collagen at doses below or around what has been individually studied. Where a benefit exists it is usually attributable to a single studied ingredient — collagen peptides at 2.5-10 g/day for skin hydration, for instance — not to the blend, and blends typically contain far less than the studied amount.

Dosage & safety

Studied doseTypical labels: biotin 5,000-10,000 mcg, vitamin C 60-250 mg, vitamin E 30-50 IU, zinc 5-15 mg, plus token silica, MSM, keratin or collagen. Studied comparators: biotin has no effective dose in non-deficient people; collagen peptides 2.5-10 g/day; zinc 15-30 mg/day only in deficiency. The gap between label dose and studied dose is the story of this category.
SafetyThe headline risk is not the ingredients but the lab interference: the FDA has issued safety communications that biotin at these doses distorts streptavidin-biotin immunoassays, producing falsely LOW troponin results — a documented cause of a missed, fatal heart attack — plus spurious thyroid and hormone panels. Stop biotin-containing supplements at least 2-3 days (longer at 10,000 mcg) before blood tests and tell any emergency clinician you take it. Zinc above 40 mg/day long-term causes copper deficiency and anemia. Formulas containing saw palmetto may affect PSA readings and are not for use in pregnancy; those containing vitamin A or high-dose vitamin E carry their own upper limits. Persistent hair loss needs a medical workup, not a supplement.

Scientific references

Where to buy

Codeage, Hair Skin Nails Vitamins, Platinum, 60 Vegetable Capsules

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