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Cyclomethicone
AKA “Cyclotetrasiloxane, Oktamethylcyklotetrasiloxan, Cyclic dimethylsiloxane tetramer, NUC silicone VS 7207, Union carbide 7207”
Synthetic
Ingredient Facts
Cyclomethicone
AKA: Cyclotetrasiloxane, Oktamethylcyklotetrasiloxan, Cyclic dimethylsiloxane tetramer, NUC silicone VS 7207, Union carbide 7207
Synthetic · Emollient · EWG: 4
Synthetic
Emollient
Solvent
Skin Conditioner
Hair Care
Silicone
Synthetic
Clean
A lightweight silicone that smooths and conditions hair and skin, leaving a soft, silky finish without heavy buildup.
Formula
C10H30O5Si5
Mol. Weight
370.77
CAS #
69430-24-6, 556-67-2, 541-02-6, 540-97-6
Form
Liquid
State
Liquid
See origin →
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 1970s-1980s. Developed as a volatile silicone fluid for cosmetics, providing a dry, non-greasy feel while improving product spread and texture compared to traditional mineral oils.
Skin Types
●all-skin-types
Best For
General
Melanin-Rich Skin
Suitable
Pregnancy & Breastfeeding Safe
Yes
EWG
4
CIR
Safe w/Qualifications
Pregnancy
Yes
CIR Safety Findings
medical-approval
all-shades-safe
Regulatory Status
USA✔ permitted
EU✔ permitted
JAPAN✔ permitted
CANADA✔ permitted
Final Report on the Safety Assessment of Cyclomethicone
Cosmetic Ingredient Review (CIR) Expert Panel
International Journal of Toxicology
→
Final Report: Safety Assessment of Polymerized Tetramethylcyclotetrasiloxanes as Used in Cosmetics
Cosmetic Ingredient Review (CIR) Expert Panel
International Journal of Toxicology
→
Safety assessment of Cyclomethicone, Cyclotetrasiloxane, Cyclopentasiloxane, Cyclohexasiloxane and Cycloheptasiloxane
Cosmetic Ingredient Review (CIR) Expert Panel
International Journal of Toxicology
→
Cyclomethicone
European Commission
EU Cosmetic Ingredient Database (CosIng)
→
Cyclotetrasiloxane
European Commission
EU Cosmetic Ingredient Database (CosIng)
→
Cyclomethicone
Environmental Working Group (EWG)
EWG Skin Deep Cosmetics Database
→
Cyclotetrasiloxane
Environmental Working Group (EWG)
EWG Skin Deep Cosmetics Database
→
Safety assessment of cyclomethicone, cyclotetrasiloxane, ...
Wilbur Johnson, Wilma F Bergfeld, Donald V Belsito, Ronald A Hill, Curtis D Klaassen, Daniel C Liebler + 5 more
International journal of toxicology, 2011
→
Safety assessment of cyclomethicone, cyclotetrasiloxane, ...
Wilbur Johnson, Wilma F Bergfeld, Donald V Belsito, Ronald A Hill, Curtis D Klaassen, Daniel C Liebler + 5 more
International journal of toxicology, 2011
→
Safety assessment of cyclomethicone, cyclotetrasiloxane, cyclopentasiloxane, cyclohexasiloxane, and cycloheptasiloxane.
Johnson W Jr, Bergfeld WF, Belsito DV, Hill RA, Klaassen CD et al.
International journal of toxicology, 2011
→
Safety assessment of cyclomethicone, cyclotetrasiloxane, cyclopentasiloxane, cyclohexasiloxane, and cycloheptasiloxane.
Johnson W Jr, Bergfeld WF, Belsito DV, Hill RA, Klaassen CD et al.
International journal of toxicology, 2011
→
Safety assessment of cyclomethicone, cyclotetrasiloxane, cyclopentasiloxane, cyclohexasiloxane, and cycloheptasiloxane.
Johnson W Jr, Bergfeld WF, Belsito DV, Hill RA, Klaassen CD et al.
International journal of toxicology, 2011
→
Verified Feb 2026
Data: PubChem · CosIng · EWG · CIR