Science
Mechanism of Action
As a hydrophilic glycoprotein, SERICA operates primarily as a powerful humectant, leveraging its rich amino acid profile to attract and retain moisture within the skin. This profile closely mimics the skin's natural moisturizing factor (NMF), thereby bolstering skin hydration. It forms a gentle, semi-occlusive film on the skin surface, which is instrumental in reducing transepidermal water loss (TEWL) and offering protection against environmental irritants. This action contributes directly to improved skin elasticity, smoothness, and the natural production of collagen. Beyond hydration, SERICA also exhibits antioxidant, antibacterial, anti-inflammatory, and anti-tyrosinase properties, aiding in skin regeneration and promoting a more uniform skin tone.
Research
Clinical Evidence
High confidenceN/A
Key findings
- 01 Hydrolyzed sericin was successfully incorporated into skin lotions, demonstrated stability for three months under accelerated conditions, proved non-irritating, and was well-tolerated. This concentration was noted for its effectiveness as a sensory enhancer.
- 02 A 2% sericin solution exhibited a significant antibacterial effect, reducing colonies of common pathogens such as Streptococcus pneumoniae, Pseudomonas aeruginosa, and E. coli from 146 to 29 over a 7-day treatment period.
- 03 At 3%, sericin solution showed moisture absorption comparable to 60% glycerol, critically achieving this benefit without contributing to pore occlusion.
- 04 An 8% sericin cream led to a significant increase in skin hydration and a reduction in skin pigmentation, observed in renal patients experiencing dry and itchy skin.
- 05 Sericin-based nanofiber films, when used as eye contour patches, enhanced skin elasticity by 35.1% and improved smoothness (R_a: −30.7%, R_z: −26.6%) in a clinical trial involving 20 participants, although a decrease in hydration was noted in this specific format.
Transparency
Dusting Analysis
Information regarding common dusting practices for SERICA is not available. However, clinical studies demonstrate measurable efficacy at concentrations as low as 0.01% for sensory enhancement in skincare formulations, suggesting functional benefits at low inclusion rates.
The Formula
Formulation
Stability
SERICA exhibits stability across a pH range of 4.0 to 8.0; however, exposure to extreme pH levels can lead to degradation. For cosmetic-grade applications, the optimal pH range is typically narrower, between 4.5 and 7.0. While native sericin can present formulation challenges due to its gelling behavior, hydrolyzed sericin is readily incorporated. Hydrolyzed sericin's limited solubility in alcohol can pose difficulties for formulations with an alcoholic base.
Conflicts
- extreme pH levels
- alcoholic base formulations (for hydrolyzed sericin due to limited solubility)
Safety
Safety Profile
The Cosmetic Ingredient Review (CIR) Expert Panel has concluded that SERICA and other silk protein ingredients are safe for cosmetic use, based on sufficient data demonstrating low toxicity. The panel specifically noted that hypopigmentation is not a concern at the low use concentrations typically found in cosmetics (e.g., 0.00047%). The maximum reported use concentration for silk powder (which contains sericin) in leave-on products, such as face powders, was 1.4%. Acute oral toxicity studies on hydrolyzed silk in rats showed low toxicity, and animal studies indicated no skin irritation or sensitization.
Your Skin
Skin Compatibility
Our Assessment
Verdict
SERICA is a valuable multi-functional ingredient, offering significant hydration, robust barrier protection, anti-aging, and skin-soothing benefits, with broad skin compatibility and a strong safety profile.
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References
Sources