Hydrolyzed keratin

ProteinHydrolyzed proteinBest with a meal

What is it

Hydrolyzed keratin is the structural protein of hair, skin, and nails (sourced from sheep wool, feathers, or other animal sources) broken down enzymatically or chemically into smaller peptides for oral or topical use.

Evidence for 1 use

AI-assisted evidence assessment — talk to your doctor before relying on any single supplement.

Hair quality (oral keratin peptides)

Limited Evidence

Small RCTs of branded oral keratin ingredients suggest modest improvements in hair strength and shedding; evidence is preliminary.

How it works

Hydrolyzed keratin provides cysteine-rich peptides and amino acids. Topically, keratin peptides can bind to hair shafts and improve mechanical properties. Orally, the protein is digested into amino acids that contribute to overall amino acid pool; whether intact peptides reach hair follicles in meaningful amounts is debated. A few small studies of branded oral keratin ingredients (e.g., functional keratin) suggest modest effects on hair thickness and shedding, but evidence is limited.

Dosage

There is no RDA. Branded oral keratin ingredients have been used at around 500 mg/day. DSLD does not provide a median dose for this entry.

When and how to take it

Take with food. Daily use over 3-6 months is typical for hair-targeted outcomes.

1 commercial form

Compare the main delivery options and what they’re best suited for.

Hydrolyzed keratin (functional keratin)

Used in hair-focused supplements.

Broken-down peptides absorb similarly to other dietary proteins.

Safety

Generally well tolerated. Allergic reactions are rare but possible with animal-derived proteins.

Who should be cautious

Vegetarian/vegan: keratin is animal-derived. Pregnancy/breastfeeding: limited data on concentrated supplements; food-equivalent intake is fine.

Interactions

No significant interactions reported.

Frequently asked questions

Will hydrolyzed keratin regrow hair?⌄

Evidence is limited. It may modestly support hair quality but is not a substitute for treatments for clinical hair loss.

Is it vegan?⌄

No. Keratin is sourced from animal tissues (often wool or feathers).

References

Hydrolyzed keratin on NIH DSLD (US supplement label database) — NIH Dietary Supplement Label Database link

Research on Hydrolyzed keratin (PubMed search) — PubMed link

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Evidence-based·How we grade evidence

Disclaimer: These statements have not been evaluated by the FDA. This page is educational, not a substitute for personalized medical advice. Evidence grades are AI-assisted assessments — talk to your doctor before starting any new supplement, especially if you’re pregnant, breastfeeding, on medications, or managing a chronic condition.