The Scientific Committee on Consumer Safety (SCCS) has determined that cyclopentasiloxane (D5) (CAS# 541-02-6, EC# 208-764-9) in cosmetic products is safe at the reported concentrations, except for use in hair styling aerosols and sun care spray products.
Cyclopentasiloxane is widely used in cosmetic products due to its unique functions as anti-static, emollient, humectant, solvent, and viscosity controlling and hair conditioning agent.
Uses Where D5 is Safe
The SCCS said it considers the use of cyclopentasiloxane (D5) in cosmetic products safe at the reported concentrations, which were at 10%, 25%, 50% and 100% in tests for skin sensitization, except in hair styling and sun care sprays.
Warning for Aerosols
Indeed, for these products, at the maximal concentrations declared by the applicant and based on the hypothesis retained by SCCS, exposure to D5 may lead to air concentrations above the value where SCCS considered that D5 may be aerosolized and locally toxic, the organization found.
According to the SCCS, exposure to D5 from hair styling sprays also triggers high levels of aggregated exposure, which may also lead to concentrations in the air above the value considered safe by the SCCS.
Note that this opinion does not cover the use of cyclopentasiloxane (D5) in oral care products.
Guilt By Association
Furthermore, the SCCS found that cyclopentasiloxane (D5) may contain traces of cyclotetrasiloxane (D4), which is classified in the EU as toxic to reproduction. Therefore, the level of impurity of cyclotetrasiloxane (D4) as an impurity of cyclopentasiloxane (D5) should be kept as low as possible.
SCCS is aware that restrictions on D4 and D5 in personal care products have been proposed under the REACH regulation due to environmental issues.