Evidence supporting the use of: Keratin
For the health condition: Fingernails (weak or brittle)
Synopsis
Source of validity: Scientific
Rating (out of 5): 2
Keratin is a fibrous structural protein that is a primary component of human hair, skin, and nails. The rationale for using keratin to support or treat weak or brittle fingernails is based on the fact that fingernails are composed largely of hard keratin. Some topical nail care products and oral supplements claim to provide keratin (or its amino acid building blocks) to support nail strength. However, scientific evidence supporting the direct efficacy of topical or oral keratin supplements for improving nail strength is limited and mixed.
Most research focuses on biotin and other nutrients rather than isolated keratin. While a few studies suggest oral supplementation with certain proteins or amino acids may benefit nail growth or strength, direct evidence for keratin supplementation is sparse. Nail health can be affected by systemic nutritional status—especially protein intake—but there is little high-quality, peer-reviewed clinical data showing that applying or ingesting keratin itself significantly improves weak or brittle fingernails in otherwise healthy individuals.
Some professional nail treatments use hydrolyzed keratin in topical formulations, and anecdotal reports suggest some benefit. However, the ability of these large proteins to penetrate the nail plate and induce structural change is questionable. In summary, scientific evidence for keratin's efficacy in treating weak or brittle fingernails is weak (evidence rating: 2/5), with most support being theoretical or based on the nail's natural composition rather than robust clinical trials.
Other health conditions supported by keratin
Fingernails (weak or brittle)Hair Care (general)
Skin Care (general)
Wounds and Sores