1 00:00:00,000 --> 00:00:08,100 What is cyclopentasiloxane? Cyclopentasiloxane,  also known as decamethylcyclopentasiloxane or D5,   2 00:00:08,100 --> 00:00:13,320 is a type of silicone, often used in  cosmetics, personal care products, and   3 00:00:13,320 --> 00:00:19,140 certain medical applications. Its main function  is as a conditioner, delivery agent, lubricant,   4 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   5 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,   6 00:00:32,400 --> 00:00:38,400 meaning it evaporates quickly, leaving behind  no residue or build-up. Despite these benefits,   7 00:00:38,400 --> 00:00:43,980 there are concerns about its environmental  impact. While generally considered safe for   8 00:00:43,980 --> 00:00:47,880 human use, it's non-biodegradable  and persistent in the environment,   9 00:00:47,880 --> 00:00:52,980 which has led to regulatory scrutiny  and calls for alternatives. It's still   10 00:00:52,980 --> 00:00:57,120 widely used, but manufacturers are  exploring more sustainable options.