Cyclotetrasiloxane
AKA: Oktamethylcyklotetrasiloxan, Cyclic dimethylsiloxane tetramer, NUC silicone VS 7207, Union carbide 7207
Synthetic
Emollient
Solvent
Skin Conditioner
Hair Care
Silicone
Not Clean
Octamethylcyclotetrasiloxane
Formula
H8O4Si4
Mol. Weight
184.40
CAS #
556-67-2, 293-51-6
Form
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.
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 oligomer synthesized in the mid-20th century. Developed for cosmetics as an ultra-lightweight volatile emollient and spreading agent offering a silky feel superior to traditional plant oils.
EWG
10
CIR
Safe as used
Pregnancy
Yes
CIR Safety Findings
medical-approval
all-shades-safe
Regulatory Agencies
🧂Conflict of interest.
Skin Types
●all-skin-types
Best For
General
Pregnancy & Breastfeeding Safe
Yes
The paper trail
🔬Peer-reviewednone on file
⚖️Regulatory1 listing →
🛡️Safety-assessed3 reviews →
Counts, not a verdict. A listing isn't a study. The trail, you decide.
Verified Jun 2026 · 🧪 = conflict
Data: PubChem · CosIng · EWG · CIR