In beauty products, cyclopentasiloxane is mainly used as a conditioner, delivery agent, lubricant and solvent, as it gives a silky and slippery feeling to the touch once applied to the hair and skin.
According to the ingredient’s material safety data sheet, cyclopentasiloxane may cause mild skin and eye irritation, but when assessed in 2010 the SCCS concluded that it does not pose a risk to human health when used in cosmetics products.
The latest opinion published still deems it safe, except in body lotion and hair styling formulations, and in products that can give rise to lung exposure through inhalation, such as aerosols, pressurised sprays and powders.
“This is because Margin of Safety based on the Point of Departure is less than 100 for the oral and inhalation routes, using the maximum concentrations reported by the applicant of 92% and 85% of D5 respectively in the finished product for application in body lotion and hair styling formulations in inhalable delivery forms,” says the Opinion.
“Aggregate exposure to Cyclopentasiloxane (D5) via cosmetic products is not safe as driven by the use of body lotion and hair styling aerosol with high concentrations of Cyclopentasiloxane (D5).”
It is recommended that the level of purity of D5 in cosmetics on the market should be at least 99%.
The Opinion also states 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 D4 as an impurity of D5 should be as low as possible.
Other concerns of cyclopentasiloxane (D5) have been its effect on the environment, although the SCCS notes did not look at this.