★What is Silk Fibroin?
Silk Fibroin is a natural protein extracted from silk, mainly composed of glycine, alanine and serine. It has good biocompatibility, moisture retention and film-forming properties, and is widely used in cosmetic formulations.
★What are the main cosmetic benefits of Silk Fibroin?
It can lock skin moisture, improve skin dryness and roughness; form a thin protective film on the skin surface to resist external irritation; help repair damaged skin barrier; and has a mild texture, suitable for sensitive skin.
★What is the solubility of Silk Fibroin for cosmetic formulation?
It is highly water-soluble, easy to dissolve in deionized water, and insoluble in oil. It is suitable for water-based formulations such as lotions, serums, masks and toners.
★Is Silk Fibroin allowed to be used in cosmetics in major regions (China, EU, US, South Korea, Japan)?
- China: Included in the Catalogue of Used Cosmetic Ingredients (2021 Edition);
- EU: Compliant with Cosmetics Regulation 1223/2009;
- US: Recognized as safe by FDA, compliant with MoCRA regulations;
- South Korea: Reportable to MFDS for circulation;
- Japan: Permitted, compliant with Pharmaceutical and Medical Device Law.
★What formulation considerations should be paid attention to when adding Silk Fibroin?
Control pH at 4.5-6.5; avoid high temperature (>80℃) and strong oxidants; control concentration (0.5%-5% for leave-on, 1%-40% for rinse-off); match appropriate preservatives; adjust texture to avoid stickiness.
★Is Silk Fibroin safe for sensitive skin?
Yes. It is a natural protein with mild properties, no obvious irritation, and can reduce skin sensitivity, making it suitable for sensitive and fragile skin types.
★Can Silk Fibroin be mixed with other cosmetic ingredients?
It is compatible with most water-soluble ingredients (humectants, preservatives, water-soluble vitamins), but incompatible with strong oxidants and cationic surfactants (may cause precipitation).
★Which well-known cosmetic brands use Silk Fibroin?
Several well-known international and Asian cosmetic brands, including Tatcha, Swissline, Kallos Cosmetics, INOHERB, Si An Yan, BOSIROU and Siusuelle, use Silk Fibroin in their skincare and haircare products for its moisturizing, soothing, anti-aging and other benefits.
★What formulation considerations should manufacturers pay attention to when adding Silk Fibroin?
When adding Silk Fibroin, manufacturers should focus on its high purity (low impurities like sericin, consistent molecular weight), optimize solubility/dispersion to avoid aggregation, ensure compatibility with co-ingredients, and tune its structure for target degradation/mechanical properties.
