Twinlab Ultimate Diet Fuel contains thermogenic fat fighting ingredients along with Cyclo Burn proprietary herbal blend to promote weight lose.* One of Ultimate Diet Fuel\ s thermogenic ingredients is Caffeine. Caffeine is a power & energy accelerant!* It\ s perfect to super energize your body for powerful workouts.* This fast-acting substance delivers the right molecular structure to your energy systems for optimal energy & power output.* Caffeine acts to increase mental alertness & neurologically provide the surge you need to support your training.* Not just a stimulant, this powerful substance reaches deep into the muscle cell to provide lasting power & delaying the onset of muscle fatigue.*