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Ker2.5

Keratin Research

Mostly mechanism / observationalHigh safety

3 peer-reviewed studies

What the evidence says

Mostly mechanism / observational

Most Keratin studies are mechanism or observational rather than RCTs that measure a clinical effect — keep findings provisional.

Most evidence is from mixed-quality randomised trials published 2013–2025 with a typical study size of 50 participants.

Based on 3 studies · 2 RCTs · 50 total participants

Confidence

Low

By outcome

Skin healthSmall industry-funded RCTs report improved hair strength, nail appearance, and skin parameters; no independent replication · ~90 days in the trials
Too few graded studies1 study

Active research area

1 study in the last 5 years

201320192025

1RCTn=50 · small study2014

Subjects taking Cynatine HNS showed statistically significant improvements in hair and nails versus placebo over 90 days.

Beer C, Wood S, Veghte RH · ScientificWorldJournal (2014)

Randomized, double-blind, placebo-controlled trial in 50 women (25 active, 25 placebo)
Active group took 500 mg solubilized keratin plus vitamins/minerals daily for 90 days
Reported significant improvements in hair loss, strength, luster, and nail strength/appearance

View source

2RCT2025

90 days of oral feather keratin hydrolysate improved skin roughness, wrinkles, elasticity, and nail/hair parameters versus placebo.

Tursi F, Nobile V, Cestone E, et al. · J Cosmet Dermatol (2025)

Three-arm RCT: 500 mg or 1000 mg feather keratin hydrolysate vs placebo in adult women
Both doses improved skin roughness, wrinkles, moisturization, elasticity, and nail hardness
Authors are affiliated with the testing company and the ingredient manufacturer (BCF Life Sciences)

View source

3In Vitro2013

Enzymatically-produced keratin peptides applied topically improved hair-fiber hydration and cuticle sealing in vitro.

Villa AL, Aragão MR, Dos Santos EP, et al. · BMC Biotechnol (2013)

Laboratory study producing keratin peptides and testing them in topical hair formulations
Improved hair hydration and cuticle sealing (brightness/softness) on treated fibers
Topical/in-vitro cosmetic-formulation work — does not address oral supplementation

View source

View in Research Library

Keratin Research

Mostly mechanism / observational

A clinical trial to investigate the effect of Cynatine HNS on hair and nail parameters.

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.

Feather keratin hydrolysates obtained from microbial keratinases: effect on hair fiber.