I cannot emphasize enough that you thoroughly investigate any over the counter diet supplements before you buy them. You don't have to have a pair of discount prescription glasses to get a real good look at those labels. If any of the label says something about a secret ingredient then put that product back on the shelf. Familiarize yourself with chemical names of common ingredients like the chemical name for salt or iron.
Keep in mind that many diet products are untested and unregulated by the FDA. It is not until there are deaths attributed to a product will the FDA step in and take a product off of the market. Protect yourself and your health and read those product labels.