Fibroin
AKA “silk fibroin, fibroin protein
Synthetic
Ingredient Facts
Fibroin
AKA: Silk fibroin, Fibroin protein
Synthetic · Film Forming · EWG: 4
Synthetic
Occlusive
Skin Conditioner
Synthetic
Clean
A natural protein derived from silk that helps create a smooth, luxurious texture and adds body to formulas.
CAS #
9007-76-5
Form
Liquid
See origin →
Functions
Skin Conditioning
A catch-all term for ingredients that improve how skin looks and feels — softer, smoother, more supple. The workhorse behind most moisturizers.
Film Forming
Creates a physical seal on skin to lock moisture in and keep irritants out. The "slugging" ingredient — barrier protection.
Bulking
Anti-Inflammatory
Moisturizing
Locks in moisture to keep skin soft and supple throughout the day
Boosts Collagen
Adds volume
Traditional Use
Fibroin is a protein extracted from silk cocoons, used in cosmetics since the mid-20th century. Silk has been valued in Asian skincare for centuries, but the isolated protein ingredient is a modern scientific extraction designed to provide skin-conditioning and film-forming properties.
Skin Types
all-skin-types
Best For
Loss of Elasticity
Melanin-Rich Skin
Suitable
Pregnancy & Breastfeeding Safe
Yes
EWG
4
CIR
Safe
Pregnancy
Yes
CIR Safety Findings
Not Phototoxic
medical-approval
all-shades-safe
Regulatory Status
USApermitted
EUrestricted
JAPANrestricted
CANADArestricted
Fibroin
European Commission
EU Cosmetic Ingredient Database (CosIng)
Hydrolyzed Fibroin
European Commission
EU Cosmetic Ingredient Database (CosIng)
Fibroin
Environmental Working Group (EWG)
EWG Skin Deep Cosmetics Database
Optimizing interactions between soluble silk fibroin and capryl glucoside for design of a natural and high-performance co-surfactant system.
Maxwell R, Costache MC, Giarrosso A, Bosques C, Amin S
International journal of cosmetic science, 2021
Silk Fibroin Biomaterials and Their Beneficial Role in Sk...
Łukasz Mazurek, Mateusz Szudzik, Mateusz Rybka, Marek Konop
Biomolecules, 2022
Silk Fibroin Biomaterials and Their Beneficial Role in Skin Wound Healing.
Mazurek Ł, Szudzik M, Rybka M, Konop M
Biomolecules, 2022
Silk Fibroin Biomaterials and Their Beneficial Role in Skin Wound Healing.
Mazurek Ł, Szudzik M, Rybka M, Konop M
Biomolecules, 2022
Allantoin-functionalized silk fibroin/sodium alginate tra...
Haojiang Xie, Qiao Bai, Fankai Kong, Yang Li, Xiaoying Zha, Lingqin Zhang + 4 more
International journal of biological macromolecules, 2022
[Heterologous expression of bacterial tyrosinase and its applications in biological hair dyeing and DOPA modification of hydrolyzed silk fibroin].
Zheng Y, Xu R, Wang Y, Fang C, DU G et al.
Sheng wu gong cheng xue bao = Chinese journal of biotechnology, 2024
Verified Feb 2026
Data: CosIng · EWG · CIR