Comparison guide
Biotin or collagen for hair?
Both are marketed for hair, skin and nails, but neither has a controlled trial showing better hair in healthy people. Biotin helps only in genuine deficiency, which is rare on a normal diet, and collagen's evidence is for skin elasticity and hydration, not hair.
The options, compared
| Option | Evidence | Best for | The honest note | |
|---|---|---|---|---|
| Biotin (Vitamin B7) | Limited evidence | Only confirmed biotin deficiency | No placebo-controlled trial shows a hair benefit in people with normal biotin status, and typical 5–10 mg doses distort lab tests such as troponin and thyroid panels. Stop it 48–72 hours before any blood test and tell the lab. | View |
| Collagen Peptides | Moderate evidence | Skin, not hair | Trials give moderate evidence for skin elasticity and hydration after 8–12 weeks at 2.5–10 g/day, but none of its graded claims covers hair. It is very safe, essentially an incomplete protein. | View |
Our verdict
For hair, neither is worth buying unless a clinician has found a biotin deficiency. If skin is also a goal, collagen has the better evidence and fewer downsides; skip high-dose biotin, whose most important real-world effect is distorting blood tests.