Hydrolyzed Keratin is a large fibrous protein broken down into smaller peptide chains through enzymatic or chemical hydrolysis. This ingredient functions primarily as a film-former and humectant, significantly enhancing the moisture-binding capacity of the skin and hair surface.
- INCI Name:
- Hydrolyzed Keratin
- Chemical/Scientific Name:
- Keratin Hydrolysates
- Common Aliases:
- Hydrolyzed Animal Protein, Keratin Peptides
| Category: | Moisturizers |
| Source Origin: | Animal-derived (Sheep’s wool, feathers, or horns) |
| Comedogenic Rating: | 0 |
| Primary Industries: | Hair Care, Skin Care, Nail Care |
| Solubility: | Water-soluble |
At a Glance: Properties & Effects
| Hydration/Moisture: | |
| Barrier Repair: | |
| Texture Enhancement: | |
| Irritation Risk: |
Primary Benefits:
- Increases skin elasticity and surface smoothness.
- Forms a protective, breathable film to reduce trans-epidermal water loss (TEWL).
- Strengthens the structure of brittle nails and hair shafts.
- Supplies essential Amino Acids to the stratum corneum.
Potential Risks:
- May cause rare allergic reactions in individuals sensitive to specific animal proteins.
- Ineffective if the molecular weight of the hydrolysate is too high for the specific formulation goal.
Biological Action & Cosmetic Profile
Topically applied protein fragments serve as highly effective humectants. By breaking down the dense, insoluble keratin molecule into smaller peptides via hydrolysis, formulators create a substance that can interact with the skin’s surface. These peptides possess a high concentration of cystine, an amino acid that enables disulfide bridging, which contributes to the structural integrity of the skin’s outermost layers.
Moisture retention occurs because these protein chains contain numerous hydrophilic (water-attracting) groups. Once applied, the ingredient binds to the keratin naturally present in the skin, creating a cohesive film. This film fills in microscopic gaps in the skin barrier, resulting in an immediate tactile improvement in smoothness and a reduction in the appearance of fine lines caused by dehydration.
Molecular weight determines the depth of action. Low molecular weight peptides may penetrate the upper layers of the stratum corneum to provide deep hydration, while higher molecular weight fractions remain on the surface to provide film-forming protection. In hair care, this mechanism is utilized to temporarily repair the cuticle, though in skincare, the primary focus remains on moisture regulation and texture refinement.
Broader Applications & Origins
Sourcing for this ingredient typically involves the processing of upcycled materials from the textile or food industries, such as wool or feathers. Advanced processing ensures the removal of impurities while maintaining the bioactive sequence of the peptides. Beyond basic moisturizing, it is frequently utilized in professional nail hardening treatments and post-procedural skin recovery balms due to its biocompatibility with human tissue.
Routine Integration
Synergies:
- Combine with Panthenol to improve deep-seated moisture retention and soothing effects.
- Use alongside Glycerin or Urea to maximize the humectant capacity of a formulation.
- Pair with Collagen for comprehensive surface film-forming and skin-plumping benefits.
Conflicts:
- High concentrations of strong Alpha Hydroxy Acids (AHAs) may theoretically degrade the protein film if applied simultaneously, though they are often formulated together in stabilized products.
Clinical Consensus & Safety
The Cosmetic Ingredient Review (CIR) Expert Panel has evaluated keratin-derived ingredients and concluded they are safe for use in cosmetics. Because the hydrolyzed form is a natural constituent of the human body’s structural matrix, it exhibits excellent skin compatibility and a very low sensitization potential. Clinical studies published in dermatological journals emphasize that while it cannot “permanently” repair skin or hair, it provides significant temporary improvement in barrier function and tensile strength. Regulatory bodies like the SCCS maintain no restrictive concentration limits, provided the source material meets purity standards and is free from prohibited bovine-derived pathogens.
Is Hydrolyzed Keratin vegan?
Standard Hydrolyzed Keratin is typically derived from animal sources such as wool or feathers and is not vegan. Formulations seeking vegan alternatives often use “Plant Keratin,” which is a blend of proteins derived from wheat, corn, or soy that mimics the amino acid profile of animal keratin.
Can it penetrate the skin deeply?
Most hydrolyzed proteins act primarily on the surface or within the topmost layers of the stratum corneum. While the hydrolysis process reduces molecular size, the peptides are generally still too large to reach the dermis, making them excellent surface conditioners rather than deep cellular modifiers.
Is it suitable for sensitive skin?
Yes, this ingredient is generally considered non-irritating and is often included in products designed for sensitive or compromised skin to help reinforce the moisture barrier.