Dimethicone/Silsesquioxane Copolymer
AKA: Silicone Copolymer, Silicone Resin
Synthetic
Occlusive
Skin Conditioner
Hair Care
Silicone
Clean
Dimethicone/Silsesquioxane Copolymer is a siloxane polymer consisting of methyl trimethoxysilane and dimethylsiloxane
CAS #
68440-84-6
Form
Liquid
State
Solid
Functions
Film Forming
Creates a physical seal on skin to lock moisture in and keep irritants out. The "slugging" ingredient — barrier protection.
Hair Conditioning
A catch-all term for ingredients that improve how skin looks and feels — softer, smoother, more supple. The workhorse behind most moisturizers.
Hair Fixing
Creates Protective Barrier
Conditions Hair
Creates protective layer
Softens and detangles hair
Holds hair in place
Traditional Use
A copolymer combining silicone with silsesquioxane compounds developed for cosmetics in the late 20th century. Used to improve texture, film-forming ability, and durability in makeup and skincare products.
EWG
2
CIR
Safe as used
Pregnancy
Yes
Restricted By
CIR Safety Findings
Not a Sensitizer
medical-approval
all-shades-safe
Regulatory Agencies
Skin Types
●all-skin-types
Best For
General
Pregnancy & Breastfeeding Safe
Yes
The paper trail
🔬Peer-reviewednone on file
⚖️Regulatory1 listing →
🛡️Safety-assessed2 reviews →
Counts, not a verdict. A listing isn't a study. The trail, you decide.
Verified Jun 2026
Data: CosIng · EWG · CIR