A study is revealing the dangers associated with over-the-counter supplements. The study published by JAMA Network Open on Friday says many of the products contain unapproved and unregulated pharmaceutical active ingredients. These dietary supplements may promise to make consumers skinny or bulk them up into bodybuilders, but officials say the substances pose a serious public health concern. One active ingredient found in certain weight loss supplements is a substance that is banned in the U.S. because of cardiovascular risks. Researchers say an estimated 50% of Americans consume some type of supplement, contributing to a $35 billion industry.