Caprylyl Methicone
Also known as Caprylyl methicone, 1,1,3,5,5,5-heptamethyl-3-octyltrisiloxane, Octyl methicone
“CIR Expert Panel says: safe as used in cosmetics.”
Caprylyl Methicone (CAS 17955-88-3) is a branched silicone with a caprylyl (C8) side chain on a methicone backbone, used as an emollient and skin-conditioning agent. The CIR Expert Panel (Final Report 03/2022) assessed it as one of 30 substituted-methicone polymers and concluded it is safe when formulated to be non-irritating, with insufficient data to determine safety for airbrush inhalation exposure. Toxicological studies found dermal and oral LD50 > 2000 mg/kg bw, NOAEL > 1000 mg/kg bw/d in 28-day repeat-dose studies, non-genotoxic in Ames and micronucleus assays, and no adverse developmental or reproductive effects at doses up to 1000 mg/kg bw/d. Dermal penetration is deemed unlikely due to low water solubility and a log Pow of 9.
Lightweight silicone emollient providing a dry, non-greasy skin feel
Compatible with both other silicones and natural plant oils
Dermal penetration deemed unlikely (log Pow 9, low water solubility)
Non-genotoxic in bacterial reverse mutation and mammalian micronucleus assays
NOAEL > 1000 mg/kg bw/d in 28-day rat studies; no developmental toxicity at same dose level
- · Insufficient data to determine safety for incidental inhalation in airbrush cosmetic applications
CIR Quick Reference Table (October 2024) — CAPRYLYL METHICONE row: Finding=SQ;I, Citation=Final Report 03/2022 Available from CIR
“Caprylyl Methicone | SQ;I | The Expert Panel for Cosmetic Ingredient Safety concluded that the following 30 dimethicone, methicone, and substituted-methicone polymers are safe in cosmetics in the present practices of use and concentration described in this safety assessment when formulated to be non-irritating, with the exception that the available data are insufficient to make a determination of safety for use of these ingredients in products that may be incidentally inhaled when applied using airbrush devices: Caprylyl Methicone | Final Report 03/2022 Available from CIR”— QRT-Update-100824_0.pdf, p. 52