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Head-to-head evidence comparison — which supplement is right for you?
Biotin vs Keratin: Biotin has the stronger overall evidence (5 vs 3/10); they're alternatives for hair growth & thickness — the best pick depends on your goals. Take the 60-second quiz for a pick tailored to your goals.
Biotin wins 2 of 3 categories. Both are solid choices — the best pick depends on your specific goals.
Verdict
Probably helps
5 of 8 studies with measurable effects showed benefit.
Top outcomes
Verdict
Mostly mechanism / observational
Top outcomes
2500-5000mcg (2.5-5mg) for hair/nails
Any time of day
Biotin capsules or tablets
~500-1000 mg hydrolyzed/solubilized keratin daily (trial-typical); Cynatine HNS trial used 500 mg keratin plus vitamins/minerals
with-meals
Solubilized keratin (Cynatine HNS) or feather keratin hydrolysate
3-6 months
3-6 months
~90 days
~90 days
Quantitative comparison of the efficacy of clinical drug treatments for primary progressive multiple sclerosis
Journal of clinical neuroscience : official journal of the Neurosurgical Society of Australasia (2023) · Meta analysis · n=3779
Among these, ocrelizumab showed outstanding performance, with wCDP% of 72.6 at 96 weeks, while the proportions of rest of the drugs ranged between approximately 55-70%.
Vitamin supplementation in the treatment of optic neuritis: A systematic review and meta-analysis
Multiple sclerosis and related disorders (2025) · Meta analysis · n=2465
The effect of MD1003 (high-dose biotin), vitamin A, and vitamin D on retinal nerve fiber layer (RNFL) thickness from pooled results showed a mean change of 0.15 (SMD 0.15, 95 % CI, -0.33 to 0.64, I2 = 61 %, τ² = 0.11, p = 0.08), which was not significant.
High-dose biotin for multiple sclerosis: A systematic review and meta-analyses of randomized controlled trials
Multiple sclerosis and related disorders (2021) · Meta analysis · n=830
Pooled data for ITW25 at 12 to 15 months yielded statistical significance (RR 2.06; 95% CI 1.04-4.09; 2 trials; 796 participants; I2 = 0%) [moderate COE] favoring HDB among patients with PMS.
A clinical trial to investigate the effect of Cynatine HNS on hair and nail parameters.
ScientificWorldJournal (2014) · Rct · n=50
Randomized, double-blind, placebo-controlled trial in 50 women (25 active, 25 placebo)
The Effects of an Oral Supplementation of a Natural Keratin Hydrolysate on Skin Aging: A Randomized, Double-Blind, Placebo-Controlled Clinical Study in Healthy Women.
J Cosmet Dermatol (2025) · Rct
Three-arm RCT: 500 mg or 1000 mg feather keratin hydrolysate vs placebo in adult women
Feather keratin hydrolysates obtained from microbial keratinases: effect on hair fiber.
BMC Biotechnol (2013) · In vitro
Laboratory study producing keratin peptides and testing them in topical hair formulations
Biotin has a higher evidence score (5/10 vs 3/10) and wins in 2 of 3 categories.
For hair growth & thickness, Keratin has a higher relevance score (55 vs 45).
No known interactions between Biotin and Keratin have been documented in our database. However, always consult a healthcare provider before combining supplements.
The right pick depends on your goals. Answer a few quick questions for a personalised recommendation — or dig into the full evidence on each.