A Practice Note on the differences in Food and Drug Administration (FDA) product categories to help practitioners determine whether a product is properly classified as a food, dietary supplement, cosmetic, medical device, or drug based on its intended use. This Note explains how a product's intended use can be gleaned from a variety of factors and how its use may be inconsistent with the product category under which it is marketed, causing the product to be misbranded, adulterated, or otherwise in violation of the Federal Food, Drug, and Cosmetic Act (FDCA).