Fat burners are supplements that essentially contain certain herbs and chemicals that either increase energy, stimulate metabolism, and/or suppress appetite. The first thing you need to understand about fat burners is that they are not all just out to help your body “burn fat” – well they are, they just get there through different mechanisms. Thermogenics, are the variation of fat burners most commonly thought of and these actually do work to help speed the metabolism, hence, helping you directly burn off more fat. Fat burners have various ingredients in them, caffeine being one of them, that will serve to help increase your energy levels again without supplying your body with calories. Taking a fat burner may help keep your concentration levels steadier, so you can maintain focus at work or any other mentally stimulating tasks you need to complete. Many of the fat burner stacks out there contain yohimbe – which while working towards decreasing body fat, will also increase blood flow to the extremities and appendages.