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Ker3.0

Keratin Research

Mostly mechanism / observational

9 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 high-quality meta-analyses and randomised trials published 2013–2026 with a typical study size of 967 participants.

Based on 9 studies · 1 meta-analysis · 5 RCTs · 967 total participants

Confidence

Moderate confidence

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
Safety profile
Too few graded studies1 study

Active research area

4 studies in the last 5 years · Latest meta-analysis: 2026

201320192026

1Meta-Analysisn=967 · large study2026

In plain English: In conclusion, supplements show promising preliminary results, but more rigorous, independent research is needed to confirm these findings.

Alanazi R et al. · Journal of cosmetic dermatology (2026)

Similarly, significant differences were observed regarding anagen proportion, elongation, and hairs extracted on a pull test (p < 0.00001 for all).
Total hair count showed no significant difference (p = 0.06).
In conclusion, supplements show promising preliminary results, but more rigorous, independent research is needed to confirm these findings.

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2RCT2018

Crum EM, McLeay YD, Barnes MJ, Stannard SR · J Int Soc Sports Nutr (2018)

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3RCT2013

Beer C, Wood S, Veghte RH · J Diet Suppl (2013)

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4RCT2025

Tursi F, Nobile V, Cestone E, De Ponti I, Lepoudere A, Sergheraert R · J Cosmet Dermatol (2025)

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5RCT2014

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

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6RCT2013

Beer C, Wood S, Veghte RH · Int J Cosmet Sci (2013)

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7Review2025

In plain English: In this article, we will discuss about the supplements available for nails, their mechanisms of action, and possible side effects.

Zaraa I, Richert B. · Skin appendage disorders (2025)

Manufacturers are not required to carry out efficacy and safety studies before marketing.
Key messages Dermatologists must be aware of the ingredients available on the market, their possible benefits but also their risks.
It is important to specify to patients that our recommendations are as solid as the available evidence.

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8Review2026

In plain English: Dietary keratins are a nutritive, safe alternative protein best extracted from wool by microwaving or feathers by acid/alkaline hydrolysis.

Haththotuwa TN et al. · Food chemistry (2026)

The strengths, challenges, limitations of current approaches, and future directions are discussed.
Dietary keratins are a nutritive, safe alternative protein best extracted from wool by microwaving or feathers by acid/alkaline hydrolysis.
Further research warranted to confirm findings

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9In Vitro2013

In plain English: 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

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View in Research Library

Keratin Research

Mostly mechanism / observational

Evaluating the Effectiveness of Commercial Oral Supplements for Hair Growth: A Systematic Review and Meta-Analysis

The effect of chronic soluble keratin supplementation in physically active individuals on body composition, blood parameters and cycling performance.

A randomized, double-blind, placebo-controlled clinical trial to investigate the effect of Cynatine® FLX on symptoms of osteoarthritis.

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.

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

A randomized, double-blind, placebo-controlled clinical trial to investigate the effect of Cynatine(®) HNS on skin characteristics.

Nail Supplements: When, How, and Why?

Valorisation of feather and wool for dietary applications and human nutrition: A step towards sustainable food production

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