Branch chain amino acids (BCAA's) fall within the category of "essential amino acids." These are the elements that help our bodies build lean muscle, which tends to help burn body fat. The downside, however, is that our bodies cannot produce BCAA's so they must be consumed within our daily diet. Generally speaking the way body builders use BCAA supplements is either right before exercise or immediately after. The powder is generally blended into smoothies to help cover its very bitter taste.