Does Biotin Really Help Hair Growth?
Quick Answer
Only if you're deficient, which is rare. Biotin deficiency causes hair loss, but most people get enough from food. Taking biotin when you're not deficient doesn't make hair grow faster or thicker. The billion-dollar hair supplement industry is mostly selling expensive pee.
Key Points
- Only works if you're actually deficient (rare)
- Most people get plenty from food
- Hair supplement industry is mostly marketing
- Nail benefits are more plausible
- Look for real causes of hair loss instead
Detailed Answer
Biotin (vitamin B7) is essential for hair keratin. That's true. But here's the thing: you're almost certainly not deficient.
THE DEFICIENCY REALITY:
• Biotin deficiency is rare. Your gut bacteria make it, and it's in tons of foods (eggs, nuts, meat, fish).
• True deficiency causes: brittle nails, hair loss, rashes, neurological symptoms
• At-risk groups: rare genetic disorders, alcoholism, pregnancy (mild depletion), long-term raw egg whites (avidin blocks biotin)
WHAT RESEARCH SHOWS:
• In deficient people: supplementation reverses hair loss. Real effect.
• In non-deficient people: No good evidence that extra biotin does anything. You pee out the excess.
• The "studies" supplement companies cite: Usually case reports of deficient people, not trials in normal people
WHY THE MYTH PERSISTS:
• Hair grows slowly. You take biotin, wait 6 months, hair seems better. Confirmation bias. It would have grown anyway.
• Marketing is powerful. Everyone wants better hair.
• Some people notice nail improvements, even without deficiency. (This is real, but modest.)
WHAT ACTUALLY HELPS HAIR:
• Iron (if deficient, especially women) • Protein (hair is protein) • Zinc (if deficient) • Vitamin D (if deficient) • Addressing underlying causes (thyroid, stress, hormones)
Evidence Quality
Few studies, preliminary findings
Key Sources:
- reviewBiotin for Hair Disorders: Review of Evidence
- guidelineNIH Biotin Fact Sheet
- reviewNutrient Deficiencies and Hair Loss: Review
Related Questions
Placebo effect, coincidental timing, or they were actually deficient (rare). Hair has natural growth cycles. People credit biotin for what would have happened anyway.
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About this information: Our recommendations draw from peer-reviewed clinical trials, systematic reviews, and the same medical databases your doctor uses. These statements have not been evaluated by the FDA. Supplements are not intended to diagnose, treat, cure, or prevent any disease.
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