"Unlike food products which are regulated by the FDA, supplements go through what's called 'post-market approval.' Anyone can legally make and sell supplements without a single clinical trial, without having to prove that what is on the label is actually in the product, and without having to do any background checks as far as the sanitation or cross-contamination of their facilities," says Angie Asche, MS, RD, CSSD, sports dietitian, and owner of Eleat Sports Nutrition.