WEBVTT 00:00:00.000 --> 00:00:08.100 What is cyclopentasiloxane? Cyclopentasiloxane,  also known as decamethylcyclopentasiloxane or D5, 00:00:08.100 --> 00:00:13.320 is a type of silicone, often used in  cosmetics, personal care products, and 00:00:13.320 --> 00:00:19.140 certain medical applications. Its main function  is as a conditioner, delivery agent, lubricant, 00:00:19.140 --> 00:00:24.960 and solvent, providing a silky, smooth feel when  applied to the skin or hair. Its low surface 00:00:24.960 --> 00:00:32.400 tension allows it to spread easily and fill in  fine lines or wrinkles. The substance is volatile, 00:00:32.400 --> 00:00:38.400 meaning it evaporates quickly, leaving behind  no residue or build-up. Despite these benefits, 00:00:38.400 --> 00:00:43.980 there are concerns about its environmental  impact. While generally considered safe for 00:00:43.980 --> 00:00:47.880 human use, it's non-biodegradable  and persistent in the environment, 00:00:47.880 --> 00:00:52.980 which has led to regulatory scrutiny  and calls for alternatives. It's still 00:00:52.980 --> 00:00:57.120 widely used, but manufacturers are  exploring more sustainable options.