Best Keratin for Hair
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Last reviewed May 2026
Clinical dose: 250–500 mg
Why Keratin for Hair
Keratin plays a supporting role in hair. Keratin is the primary structural protein of hair, skin, and nails. Supplemental keratin is typically solubilized (enzymatically hydrolyzed) to preserve bioactive disulfide bonds and improve absorption. In clinical studies, keratin reduces hair shedding and supports hair strength.
What dose to look for
Clinical studies typically use 250–500 mg of keratin. Clinical trials with Cynatine HNS use 500 mg/day. Most supplements provide 250–500 mg/day of solubilized keratin. Products below this range may not deliver meaningful results.
What the research says
Keratin has limited clinical evidence for hair benefits. Only 2 small clinical trials (12-16 weeks each) on hair, nail, and skin outcomes Learn more
Clinical research on Keratin (Oral)
VERY LOW — no robust RCTs · Not established
- •A few small studies show some improvements in hair strength metrics, but no robust placebo-controlled RCTs exist
- •Oral bioavailability of intact keratin is poorly understood — likely digested into amino acids