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

Skin Types

●all-skin-types

Best For

General

Pregnancy & Breastfeeding Safe

Yes

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

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.

EWG

CIR

Safe as used

Pregnancy

Yes

Restricted By

Concentration Guide

CIR's newest survey reports no concentration of use.

CIR · 2016 survey

Regulatory Status

USA✔ permitted

EU⚠ restricted

JAPAN⚠ restricted

CANADA⚠ restricted

Regulatory Agencies

Verified Jun 2026

Data: CosIng · EWG · CIR