The answer is somewhat far from what you expected. It is 1,2-Hexanediol
It sounds like a secret biological weapon but it is truly one of most popular ingredients in cosmetic world. About 80% of our skincare products have this ingredient. I am sure many of your cosmetics also contain it, so your skin has no choice but to rendezvous with 1,2-Hexanediol almost every day. Now wanna know about it? Huh?
Nowadays it is widely used as a preservative. But when chemists synthesized 1,2-Hexanediol first time, the main purpose was a solvent. Don’t be panic with the new term “Solvent” It simply helps oily ingredients mix with watery ones in one cosmetic. But after FDA has announced the danger of Paraben and related variants, the effective preservative of cosmetics, manufacturers had to find a non-toxic alternative, 1,2 Hexanediol. It is a bit pricey ingredient but they don’t have any other choice given the situation that consumers are getting more interested in what’s in their cosmetics.
The preservative effect of 1,2-Hexanediol is not as strong as Paraben. So normally other preservative ingredients are added to boost the effectiveness. And apart from the function of preservation, 1,2-Hexanediol also works as a moisturizing and antibacterial agent.
EWG score: 1 (=low risk)
Link: https://www.ewg.org/skindeep/ingredients/700001-1-2-hexanediol/