Hydrolyzed Keratin Powder
Also known as: Hydrolyzed keratin powder, Keratin hydrolysate, Feather keratin hydrolysate (FKH), Hydrolyzed Keratin
Overview
Hydrolyzed keratin is a protein derivative created by breaking down keratin into smaller peptides and amino acids through hydrolysis. It is primarily sourced from wool or poultry feathers. As an oral supplement and topical agent, it is used to improve hair strength, skin appearance, and nail health. It is also applied in cosmetic formulations for hair repair and protection. Hydrolyzed keratin contains a mix of free amino acids and peptides capable of penetrating hair cuticles and skin layers. The molecular weight of these peptides influences the depth of penetration. Research on hydrolyzed keratin is emerging, with several recent randomized controlled trials (RCTs) and mechanistic studies available. The quality of evidence is moderate, including RCTs with adequate sample sizes and mechanistic studies, though systematic reviews and meta-analyses are limited.
Benefits
Oral supplementation with feather keratin hydrolysate (FKH) at 500-1000 mg/day for 90 days has been shown to improve facial skin parameters such as roughness, wrinkle features, moisture, elasticity, thickness, density, and gloss, as well as hair and nail appearance and nail hardness in adult women, according to a randomized, double-blind, placebo-controlled study. Topical hydrolyzed keratin deposits on hair cuticles and penetrates the cortex, enhancing hair tensile strength and providing UV protection, which can improve hair resilience and reduce environmental damage. Secondary effects include improved hair tensile properties and potential thickening/emulsifying properties in cosmetic formulations. Adult women showing signs of physiological aging in skin, hair, and nails demonstrated measurable improvements with oral supplementation.
How it works
Hydrolyzed keratin peptides and amino acids serve as building blocks for keratin synthesis in hair, skin, and nails, promoting structural repair and regeneration. It enhances extracellular matrix components and keratinocyte function in skin. It also deposits on hair cuticles and penetrates the cortex to reinforce hair fiber structure. Oral keratin hydrolysates are absorbed as free amino acids and small peptides. Topical hydrolyzed keratin penetrates the hair cuticle and cortex, depending on its molecular weight, with peptides around 3000 Da penetrating deeper.
Side effects
Hydrolyzed keratin is generally recognized as safe, with no major adverse effects reported in clinical studies. No common side effects (greater than 5%) have been reported in well-controlled trials. Uncommon (1-5%) and rare (less than 1%) side effects are not documented. There are no known significant drug interactions or established contraindications. However, safety in pregnant or lactating women and children has not been well-studied, so caution is advised for these populations.
Dosage
For skin, hair, and nail benefits, the recommended oral dosage is 500-1000 mg/day. Clinical trials have shown efficacy with 500 mg/day, and doses up to 1000 mg/day have been used safely. Daily supplementation for at least 90 days is recommended for observable benefits. Oral capsules or powders should be standardized for amino acid content. Topical formulations for hair repair vary in concentration. Oral bioavailability depends on peptide size, while topical penetration depends on molecular weight and formulation. No specific cofactors have been identified, but general nutritional support may enhance effects.
FAQs
Is hydrolyzed keratin powder safe for daily use?
Yes, clinical trials report no significant adverse effects with daily use up to 1000 mg for 90 days.
How long does it take to see results?
Typically, 3 months of consistent use is needed for noticeable improvements in skin, hair, and nails.
Can it be used topically and orally?
Yes, topical application improves hair cuticle protection and tensile strength, while oral supplementation supports systemic keratin synthesis.
Does molecular weight affect efficacy?
Yes, smaller peptides (~3000 Da) penetrate the hair cortex better, while larger peptides mainly deposit on the cuticle surface.
Research Sources
- https://pmc.ncbi.nlm.nih.gov/articles/PMC11902160/ – This study investigates the effects of oral supplementation with feather keratin hydrolysate (FKH) on skin, hair, and nail health in adult women. The randomized, double-blind, placebo-controlled trial found significant improvements in skin parameters, hair and nail appearance, and nail hardness after 90 days of supplementation with 500 and 1000 mg/day doses compared to placebo.
- https://pubmed.ncbi.nlm.nih.gov/39367631/ – This study examines the deposition and penetration of topical hydrolyzed keratin on hair samples using SEM and fluorescence microscopy. The findings indicate that hydrolyzed keratin deposits on the hair cuticle and penetrates the cortex, enhancing tensile properties and providing UV protection, with molecular weight influencing penetration depth.
- https://pubs.acs.org/doi/10.1021/acsomega.4c10755 – This research focuses on the functional properties of hydrolyzed keratin in cosmetic formulations, assessing surface activity, emulsifying, and thickening properties of commercial hydrolyzed keratin powders. The study reveals that hydrolyzed keratin exhibits functional properties beneficial for cosmetic formulation stability and performance, potentially enhancing topical product efficacy.
- https://www.preprints.org/manuscript/202502.0629/v1/download – This preprint details a randomized, double-blind, placebo-controlled trial on oral feather keratin hydrolysate (FKH) in adult women with aging signs. The study reports significant improvements in skin roughness, wrinkles, moisture, elasticity, thickness, density, gloss, hair and nail appearance, and nail hardness at 500 and 1000 mg/day doses compared to placebo after 90 days.
- https://www.cir-safety.org/sites/default/files/keratin_0.pdf – This document from the Cosmetic Ingredient Review (CIR) provides a safety assessment of keratin-derived ingredients in cosmetics. It reviews the available data on keratin and hydrolyzed keratin, concluding that these ingredients are safe for use in cosmetic products when formulated to avoid irritation.
Supplements Containing Hydrolyzed Keratin Powder
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