Cyclomethicone
Cyclomethicone
- Role
- A silicone base and solvent that makes the formula easier to apply and spread.
- Catalog formulas
- 6
- Type
- Base
- Verified
- 09.11.2026
What does this ingredient do in an antiperspirant?
A generic name for a mixture of cyclic silicones (cyclic dimethyl polysiloxanes) with 4–6 units in the ring, i.e. D4, D5 and D6. INCI functions: solvent, emollient and hair conditioning agent.
Part of a system, not a label in isolation
In sticks and roll-ons it forms part of the silicone base in which the other ingredients are dispersed. It does not reduce sweating: that is the job of aluminium or zirconium salts.
In 2011 the CIR concluded that Cyclomethicone and the individual cyclic silicones are safe in the present practices of use, with minimal skin absorption. In the EU, D4 (Cyclotetrasiloxane) is prohibited in cosmetics (Annex II to Regulation 1223/2009, entry 1388), and Regulation (EU) 2024/1328 limits D4, D5 and D6 to below 0.1% each: for D4 and D5 in wash-off products since 31 January 2020, and for all other cosmetics, including leave-on antiperspirants, after 6 June 2027.
The CIR noted that the available data do not suggest skin irritation or sensitisation potential for these silicones; an individual reaction to the finished product is possible.
Cyclomethicone is not a single substance but a mixture of cyclic silicones; Cyclopentasiloxane (D5) is one of its components. Nor is it Dimethicone: dimethicone is a silicone polymer, not a mixture of ring-shaped siloxanes.
Products containing Cyclomethicone
Links are based on the complete published INCI list for the exact product version.
Sources
The conclusions apply to the stated conditions and jurisdictions, not automatically to every concentration or product.
- EU CosIng: Cyclomethicone Supports: INCI functions, substance identity, restrictions
- CIR: Safety Assessment of Cyclomethicone, Cyclotetrasiloxane, Cyclopentasiloxane, Cyclohexasiloxane and Cycloheptasiloxane (2011) Supports: safety assessment, skin absorption, irritation and sensitisation
- Regulation (EU) 2024/1328: restriction of D4, D5 and D6 (REACH Annex XVII, entry 70) Supports: restrictions
- Regulation (EU) 2019/831: D4 in Annex II to Regulation 1223/2009 Supports: D4 ban