MuscleTech's Hydroxycut is a thermogenic compound containing hydroxycitric acid, mahuang extract (herbal form of ephedrine), guarana extract (herbal form of caffeine), willow bark extract (herbal form of aspirin), l-carnitine, and chromium picolinate. These ingredient combine to make an effective stack for increasing the burning of fat in the body (similar to the use of the ephedrine/caffeine/aspirin stack) and helping to suppress the appetite. The Inside Scoop: This is one of our top selling weight loss products. We have received very positive feedback from our customers about the success they have had in using Hydroxycut.