Science
Mechanism of Action
Fibroin operates through multiple pathways to benefit the skin. It establishes a non-occlusive protective film, which fortifies the skin barrier and offers defense against external aggressors such as pollutants and UV radiation. Its hydrophilic amino acid profile enables potent humectant action, attracting and binding water molecules to significantly boost skin hydration and elasticity. Furthermore, Fibroin possesses natural antioxidant properties, aiding in the neutralization of free radicals and reduction of oxidative stress. Beyond surface benefits, it actively promotes skin regeneration, upregulating key cellular pathways like MEK1, PI3K, and JNK to stimulate cell migration, and enhancing NF-kB signaling to increase expression of critical components such as vimentin, fibronectin, cyclin D1, VEGF, and Type I collagen.
Research
Clinical Evidence
Medium confidenceN/A
Key findings
- 01 A 2017 randomized, single-blind, parallel-controlled clinical trial involving 71 patients demonstrated that a silk fibroin film significantly reduced wound healing time and adverse event incidence compared to standard commercial dressings.
- 02 Research in 2022 showed that thermo-responsive hydrogels, formed from 3% wt/v silk protein solutions, effectively suppressed localized inflammatory responses and accelerated epithelialization in third-degree burns within the human body temperature range.
Transparency
Dusting Analysis
While Fibroin can function as a bulking agent, its profound and scientifically supported mechanisms, including barrier fortification, hydration, antioxidant activity, and cellular regeneration, indicate its role as an active ingredient rather than merely an inert filler at low, ineffective concentrations.
The Formula
Formulation
Stability
The rate of gelation for regenerated silk fibroin solutions is dependent on both its concentration and temperature. Stability can be enhanced, as observed in blended scaffolds incorporating silk fibroin with keratin.
Conflicts
- Sericin, another silk protein, is a known potential sensitizer and should be meticulously removed during processing to ensure the purity and reduce adverse reactions of cosmetic-grade fibroin.
Safety
Safety Profile
The CIR Expert Panel affirmed silk proteins, including Fibroin, are safe for cosmetic use when formulated to be non-irritating. High-purity fibroin minimizes immunological responses; however, IgE-mediated hypersensitivity has been reported in cases involving sericin impurities or repeated surgical exposure to silk sutures. While a specific maximum concentration for Fibroin directly in cosmetics is unknown, related 'Silk Powder' has been used up to 1.4% in leave-on products. The FDA has approved silk fibroin for various biomedical applications and partially hydrolyzed silk fibroin as GRAS for certain food uses.
Your Skin
Skin Compatibility
Our Assessment
Verdict
Fibroin is a valuable multifunctional ingredient, offering robust skin barrier support, significant hydration, antioxidant protection, and promoting skin regeneration for improved elasticity and overall skin health.
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References
Sources