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Vitamin

Vitamin B7 (Biotin)

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Vitamin B7 (Biotin). Carboxylase cofactor marketed for hair, skin, and nail support.

How it works. Prosthetic group for 5 mammalian carboxylases involved in fatty acid synthesis and gluconeogenesis.

What the research supports. 2 graded claims. Strongest: Reverses brittle nails in some cases (limited).

How much to take. Typical dose: 30 mcg general; 2,500–5,000 mcg for hair/nails.

Side effects and interactions. 1 medication interaction listed. Serious: Falsely abnormal thyroid/troponin labs at high doses.

Stacking. Pairs well with Collagen peptides, Vitamin C.

Common forms. Available as D-biotin.

Key studies. 9 studies cited. The strongest are listed with links to PubMed.

Community. Experiences from people who have tried Vitamin B7 (Biotin). Anecdotes are not medical advice.

Vitamin B7 (Biotin). Carboxylase cofactor marketed for hair, skin, and nail support.

Molecular structureC10H16N2O3S · 244.31 g/mol

What it is

Carboxylase cofactor marketed for hair, skin, and nail support.

Also called

Vitamin H

Food sources

Egg yolkLiverNuts

Goals

Skin, Hair & Nails

How it works

Prosthetic group for 5 mammalian carboxylases involved in fatty acid synthesis and gluconeogenesis.

Pathways

  • Carboxylation reactions

Effects

  • +Keratin infrastructure (if deficient) supports

What the research supports

Reverses brittle nails in some caseslimited
Helps biotin-deficient hair loss onlylimited

Strong: consistent results across large trials or meta-analyses. Moderate: several trials, mostly positive. Limited: small or mixed studies. Preclinical: animal or cell research only.

Typical dose
30 mcg general; 2,500–5,000 mcg for hair/nails
TimingConsistent daily timing recommended; split larger doses if GI tolerance is a concern.
With foodWith a meal containing fat for fat-soluble compounds; otherwise either.
Best formMost evidence is based on the d-biotin form.
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Side effects & interactions

Serious

  • Falsely abnormal thyroid/troponin labs at high doses

Medication interactions

Lab assays (thyroid, troponin)moderate

Stop ≥48h before testing.

Check any supplement–medication combination with your pharmacist before starting.

Combines with

Pairs well

  • Collagen peptidesProvides amino acid substrate for connective tissue synthesis.
  • Vitamin CRequired cofactor for collagen hydroxylation.

Common forms

  • D-biotin

Key studies

9 studies cited in total.

PubMed: Vitamin B7 (Biotin) — Reverses brittle nails in some cases ↗
Systematic review · PubMed (NLM) · 2026

Opens current human and preclinical literature matching Vitamin B7 (Biotin) and "Reverses brittle nails in some cases". Filter by RCT, meta-analysis, or year on the results page.

PubMed: Vitamin B7 (Biotin) — Helps biotin-deficient hair loss only ↗
Systematic review · PubMed (NLM) · 2026

Opens current human and preclinical literature matching Vitamin B7 (Biotin) and "Helps biotin-deficient hair loss only". Filter by RCT, meta-analysis, or year on the results page.

PubMed: Vitamin B7 (Biotin) — randomized controlled trial ↗
Systematic review · PubMed (NLM) · 2026

Opens current human and preclinical literature matching Vitamin B7 (Biotin) and "randomized controlled trial". Filter by RCT, meta-analysis, or year on the results page.

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