Stacker 2 from NVE Pharmaceuticals is a complete diet formula that compares with products like Xenadrine, Hydroxycut and Ripped Fuel. Stacker 2 is specially formulated to create a thermogenic response in people with slower metabolisms. Like the other products, Stacker 2 uses caffeine as its core thermogenic ingredient, which is a an effective, proven approach for products like these.Stacker 2's botanical ingredients like green tea extract and especially White Willow bark are thought to have a synergistic effect with caffeine in terms of increasing metabolism to burn more fat. Guggulsterones have been studied for their positive effect on metabolism, possibly by affecting aspects of thyroid gland function. This 'stack' of ingredients in Stacker 2 will deliver energizing and appetite suppressant-effects right off the bat, and is great for someone just beginning a diet and exercise program who needs help in a few areas. More experienced dieters and athletes might use this product on an occasional basis, as a preworkout energy booster or anytime their workouts need an extra kick.