Cyclopentasiloxane
AKA: Silicone
Synthetic
Emollient
Solvent
Skin Conditioner
Hair Care
Silicone
Not Clean
Decamethylcyclopentasiloxane
Formula
C10H30O5Si5
Mol. Weight
370.77
CAS #
541-02-6
Form
Liquid
State
Liquid
Functions
Hair Conditioning
A catch-all term for ingredients that improve how skin looks and feels — softer, smoother, more supple. The workhorse behind most moisturizers.
Skin Conditioning
A catch-all term for ingredients that improve how skin looks and feels — softer, smoother, more supple. The workhorse behind most moisturizers.
Emollient
Fills in the tiny cracks between skin cells to make everything feel smooth and soft. The "silky finish" ingredient.
Solvent
Dissolves other ingredients so they distribute evenly in the formula. Often the invisible "base" everything else is mixed into.
Locks In Moisture
Traditional Use
A cyclic silicone polymer developed in mid-20th century silicone chemistry research. Used in cosmetics as a lightweight volatile carrier and emollient, designed to replace heavier traditional oils and waxes.
EWG
4
CIR
Safe as used
Pregnancy
Yes
Restricted By
CIR Safety Findings
medical-approval
all-shades-safe
Regulatory Agencies
Skin Types
●all-skin-types
Best For
General
Pregnancy & Breastfeeding Safe
Yes
The paper trail
🔬Peer-reviewed1 paper →
⚖️Regulatory1 listing →
🛡️Safety-assessed2 reviews →
Counts, not a verdict. A listing isn't a study. The trail, you decide.
Verified Jun 2026
Data: PubChem · CosIng · EWG · CIR