In October 2016, the European Commission's Scientific Committee for Consumer Safety (SCCS) issued an evaluation opinion on the composition of cyclopentadimethylsiloxane (D5): D5 may contain cyclotetradimethylsiloxane (Dycsiloxane) D4 is classified as a substance with reproductive toxicity in the European Union (Annex VI of Regulation (EC) No 1272/2008 (CLP Regulation)). Therefore D5 requires D4 concentration levels to be very low, and SCCS recommends D5 purity for consumer products It should be> 99%.

Cyclopentamethicone is a colorless liquid and belongs to the raw materials in the catalogue of used cosmetic raw materials (2015 edition).
Chinese name: cyclopentadimethylsiloxane
INCI name: Cyclopentasiloxane
CAS: 541-02-6
EC: 208-764-9
Chinese alias: Decamethylcyclopentasiloxane; Cyclopentasiloxane; Decamethylcyclopentasiloxane (D5)

Cyclopentadimethylsiloxane (hereinafter referred to as D5) is generally used as a volatile excipient in cosmetics. Due to its low surface tension, hydrophobicity, stability and other characteristics, it has been widely used in cosmetics, such as Antistatic, emollient, humectant, solvent, viscosity control and hair conditioner.
Based on the data provided, SCCS considers the concentration of D5 to be safe, except for hair styling spray products and sunscreen spray products, which may cause environmental problems, but the above data does not explain the environmental problems.
According to some views of the European Union and other countries, for example, the US CIR expert group believes that cyclopentadimethylsiloxane is safe under current usage and dosage conditions; the Canadian government also believes that D4 is a risky substance and may Causes environmental and reproductive toxicity, while D5 does not harm human health.
So D5 is safe under the existing usage, but in the process of use, we must pay attention to:
1. Its content is a very important factor, it must be guaranteed to be greater than 99%, and the impurity D4 that it may contain must be strictly controlled;
2. Because D4 may cause reproductive toxicity, please use it with caution in pregnant women, which may have an impact on breast milk and may cause some health problems for infants, but there is no clear data verification.