What's in it? Cyclopentasiloxane
Other names it goes by Decamethyl, Decamethylcyclopentasiloxane
What's it used in? Antiperspirant, moisturisers, hair bleach, foundations, conditioners, SPF products.
What does it do? A type of silicone used to lubricate or moisturise.
Any controversy? There are fears it may accumulate in the body, water system and wildlife. It can irritate the skin, eyes or lungs.