While browsing social media, you see that a celebrity is endorsing a new supple

 While browsing social media, you see that a celebrity is endorsing a new supplement. Their endorsement states that they have taken the supplement every day, and that it has resulted in younger looking skin. The celebrity suggests that everyone should take the supplement. 
 
Should this endorsement be taken seriously, or is there reason to be skeptical?
What other information would you want before taking the supplement?
If you saw more people endorsing the supplement, would it change your mind? Why or why not?