Common Name(s): Silk amino acids,serica protein hydrolysate,silk fibroin
CAS Number: 96690-41-4
DESCRIPTION
What It Does: Forms a silky protein film on hair and skin providing smoothing, shine, and hydration.
Why It's Used: Premium natural protein conditioner providing a unique silky film from silk fibroin's unique gly-ser-gly-ala-gly-ala repeat sequence that distinguishes silk from all other protein sources.
How It Works: Silk fibroin's unique gly-ser-gly-ala-gly-ala sequence forms beta-sheet crystalline regions in film, providing mechanical strength and smoothness. high serine content provides humectant water binding. film flexibility from alternating crystalline/amorphous regions.
Typically Found In: Luxury hair conditioners,silk serums,premium moisturizers
TECHNICAL DETAILS
Primary Category: Active ingredient – silk fibroin peptides
Secondary Functions: Skin conditioning
Application Areas:
Facial Skincare
Body Care
Hair Care
Beard Care
Color Cosmetics (Makeup)
Dietary/Oral Supplements
Typical Concentration Range: 0.5%–5%
SOURCING & ETHICS
Vegan Status: No - animal-derived
Halal Status: Contested - insect-derived; jurisdiction-dependent, refer to certifier stance (region rules)
Source Notes: Commercially produced for cosmetic use. verify vegan/halal status with supplier. [audit 2026-07-29 rev2: insect-derived; genuinely contested between certifying bodies, not resolvable by documentation. determination requires shariah-panel sign-off.]
SKIN COMPATIBILITY
Irritancy Rating: 1/5 – very low
Comedogenicity Rating: 0/5 – non-comedogenic
Sensitivity Concerns: Well-tolerated by most skin types.
Safe for Sensitive Skin: Yes
SAFETY & COMPATIBILITY
Safety Profile: Good safety profile at recommended concentrations. ewg score: 1–2.
Works Well With: Standard skincare actives
Avoid Combining With: No known significant incompatibilities
SCIENTIFIC NOTE
Silk fibroin's unique beta-sheet secondary structure (formed by gly-ala-gly-ala repeat stacking) is mechanically stronger than any other natural protein fiber per unit weight – the same molecular architecture that gives silk fabric its legendary strength and smoothness. when hydrolyzed silk reforms as a film on hair surface, remnants of this beta-sheet structure provide superior mechanical film properties vs random coil protein films.
Last Verified: 2026-03-12
Primary Sources: Cosing database,altman et al. silk fibroin review