This Friday, one of the most shocking films of the year opens – a blood-drenched body horror with an unusual theme for the genre: Hollywood’s impossible beauty standards. The Substance stars Demi Moore as a 50-year-old actor who tries a mysterious procedure that claims to “unlock your DNA and a younger version of yourself”. Literally. It’s an extreme take on a universal theme. Here, four women write about how beauty standards have affected their lives.