you should know that the FDA has cracked down on some weight loss supplements that had prescription drugs in them that weren't noted on the label. You can't always tell what you're getting. The FDA does regulate dietary supplements, but it treats them like foods rather than medications. Unlike drug manufacturers, the makers of supplements don’t have to show their products are safe or effective before selling them on the market. Here are some common ingredients found in over-the-counter supplements and herbal remedies for weight loss.