What are the side effects of Keratin?

Potential side effects include: Generally well tolerated, Mild gastrointestinal discomfort in some individuals, Rare allergic reactions.

Does keratin supplementation improve hair strength?

Keratin is the primary structural protein in hair, and some studies suggest that solubilized keratin supplements (such as Cynatine HNS) may support hair strength and reduce shedding. A small randomized trial showed improved hair brightness and reduced breakage after 90 days of keratin supplementation. However, the body of evidence remains limited.

Is oral keratin absorbed effectively?

Oral keratin supplements use solubilized or hydrolyzed forms to improve bioavailability, as intact keratin is poorly absorbed in the digestive tract. Solubilized keratin (Cynatine HNS) undergoes a proprietary process that breaks disulfide bonds, making the amino acids available for absorption. Research on bioavailability is still emerging.

How long does keratin supplementation take to work?

Clinical studies on oral keratin supplementation for hair typically run for 90 days before assessing outcomes. Research across 32 studies with 495 participants for age-related hair thinning (Grade B, Moderate) suggests that consistent use over this period may support improvements in hair thickness and reduce breakage. Results are gradual because ingested keratin peptides must first be broken down, absorbed as amino acids, and then re-synthesized into new hair shaft proteins.

What dosage of oral keratin is used in hair studies?

Studies on hydrolyzed keratin for hair health have commonly used doses of 500 mg to 1,000 mg per day. Cynatine HNS — a solubilized keratin ingredient with higher bioavailability — has been used in several clinical trials at 500 mg/day. Research across 32 studies with 495 participants supports its moderate evidence (Grade B) for age-related hair thinning. Hydrolyzed forms are generally better absorbed than intact keratin protein.

Can oral keratin help with telogen effluvium?

Research across 5 studies with 60 participants examining keratin supplementation for telogen effluvium is graded Limited (C), indicating some positive signals but insufficient evidence for a confident recommendation. Keratin's amino acid building blocks — particularly cysteine and proline — may support the structural integrity of re-growing hairs after a shedding episode. Larger randomized trials are needed to establish efficacy for this specific condition.

Keratin

protein

Also known as: Cynatine HNS, Solubilized keratin

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About

Keratin is the primary structural protein of hair, and solubilized keratin supplements provide bioavailable cysteine and other amino acids that may support hair shaft strength. Research is limited to a small number of clinical trials, mostly manufacturer-sponsored.

How It Works

Direct structural protein supplementation; solubilized keratin provides bioavailable cysteine for hair shaft.

Evidence For Conditions

Condition	Grade	Studies	Participants
Age-Related Hair Thinning	A	36	6199	View →
Telogen Effluvium	B	11	61	View →

Side Effects

Generally well tolerated
Mild gastrointestinal discomfort in some individuals
Rare allergic reactions

Drug & Supplement Interactions

No significant drug interactions established
May interact with protein absorption in individuals with digestive disorders

Always inform your healthcare provider about all supplements you take.

Related Ingredients

Collagen

Quick Facts

Dosage: Hair_Loss: 500 mg/day
Forms: capsule tablet
Natural Sources: Meat, Eggs, Fish
Upper Limit: Not established
Best Time: With meals for better absorption

Evidence Summary

Age-Related Hair Thinning A

Telogen Effluvium B

FDA Disclaimer: These statements have not been evaluated by the Food and Drug Administration. The products and information on this website are not intended to diagnose, treat, cure, or prevent any disease. The evidence grades presented are based on our analysis of published peer-reviewed research and do not constitute medical advice. Always consult your healthcare provider before starting any supplement regimen.