Dimethicone Crosspolymer
Also known as Dimethicone elastomer, Silicone elastomer (dimethicone-based), Crosslinked polydimethylsiloxane
“CIR Expert Panel says: safe as used in cosmetics.”
Dimethicone Crosspolymer (CAS 213629-14-2, specific to C5 grade) is a three-dimensional silicone elastomer formed by crosslinking polydimethylsiloxane chains with a C3–C20 alkyl group. The CIR Expert Panel evaluated 62 dimethicone crosspolymer ingredients in its 2014 group safety assessment (IJT 33(Suppl 2):65-115; PMID 24861370) and concluded all are safe as used in cosmetics. Key findings: dermal LD50 >2000 mg/kg (rabbits), oral LD50 >2000 mg/kg (rats), not mutagenic in Ames tests up to 1000 µg/plate, not irritating to human skin at 100% in repeated insult patch testing, and not sensitizing to guinea pigs at 100%. The large polymer network structure prevents skin penetration, eliminating systemic absorption concerns.
Silicone elastomer texture modifier; imparts a silky, soft-focus skin feel and reduces tackiness in formulations
Three-dimensional crosslinked polymer; does not penetrate intact skin, eliminating systemic exposure concern
CIR Expert Panel found safe as used in cosmetics across 62 crosspolymer variants:65-115, 2014)
Not irritating to human skin at 100% concentration in repeated insult patch testing; not mutagenic in multiple Ames tests
Chemically inert silicone backbone; no known sensitization potential at cosmetic use concentrations
- · CAS 213629-14-2 is specific to the C5 alkyl-crosslinked grade; other CAS numbers apply to other grades within the INCI name — no toxicological significance but relevant for regulatory traceability
Residual monomers (e.g., vinyl acetate, platinum catalyst, α,ω-divinyl alkenes) were noted as a manufacturing concern by the CIR Panel; Panel concluded levels are below toxicological concern based on available data
CIR Quick Reference Table (12/2017, revised 07/2018) — Dimethicone Crosspolymer row: Finding=S, Citation=IJT 33 (S2): 65-115, 2014
“Dimethicone Crosspolymer | S | | IJT 33 (S2): 65-115, 2014”— QRT-122017revised072018.pdf, p. 44