At a glance
- CAS number
- 541-02-6
- INCI name
- Cyclopentasiloxane
- Function
- emollient, solvent, conditioning agent, carrier
- Typical use level
- 1%–40%
- Solubility
- oil
CAS number and synonyms are sourced from PubChem. Function, usage levels, pH and compatibility are AI-assisted formulation guidance — verify against your supplier's technical data sheet and applicable regulations before use.
Also known as
Cyclomethicone 5 Dimethylsiloxane pentamer Dow corning 345 Cyclic dimethylsiloxane pentamer NUC silicone VS 7158 Silicon SF 1202 Ciclopentasiloxane Cyclomethicone D5 Dekamethylcyklopentasiloxan D5-sil Cyclopentasiloxane, 2,2,4,4,6,6,8,8,10,10-decamethyl- Lightening Serum
Compatibility
Works well with:
Dimethicone Cyclohexasiloxane Isododecane Phenyl Trimethicone Dimethiconol Nylon-12 Silica Ester Oils Waxes Volatile Alcohols
Use caution with:
Strong Acids Strong Bases High-Polarity Humectants
Cyclopentasiloxane is generally highly compatible with other silicones and many non-polar oils, making it a versatile carrier in anhydrous and emulsion systems. It does not blend well with water or high-polarity ingredients without appropriate emulsification. Strong acids or alkalis can catalyze ring-opening hydrolysis over time, potentially reducing stability.
Formulation notes
Cyclopentasiloxane (D5) is a volatile silicone that evaporates after application, leaving a non-greasy, silky feel. It is widely used in hair care, antiperspirants, foundations, and skin serums. Regulatory scrutiny has increased in the EU; under EU Regulation (EC) No 1223/2009 amendments, D5 is restricted to rinse-off cosmetics at ≤0.1% due to environmental persistence (PBT/vPvB concerns). Leave-on applications face ongoing regulatory review. Formulators should verify current regional regulatory
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