Pre-workout supplements are athletic performance supplements designed to be taken before a particularly tiring and rigorous exercise session. Their purpose is to boost muscular energy and tolerance. Even though pre-workout supplements are a fairly new addition to work-out programs, they’ve have caught on quickly. You are likely to come across a large variety of pre-workout supplements, each claiming to be the absolute best. But not every brand can be the best, especially since most contain the same formula. Some pre-workout supplements, however, contain certain ingredients that make them stand out from the rest.