The Substance (in OmdU)

Elisabeth Sparkle (Demi Moore) is an actress who is already past her prime. After she is finally fired by the sexist studio boss Harvey (Dennis Quaid), which means she no longer has a regular income and can no longer get any other roles due to her age, she falls into a dangerous downward spiral of despair - until that fateful car accident leads her to a mysterious company that offers her a mysterious substance that supposedly causes you to temporarily transform into a better version of yourself.