BCAA’s are Branched Chain Amino Acids consisting of 3 essential amino acids Leucine, Iso-Leucine, and Valine. They are considered essential amino acids because human beings cannot survive unless these amino acids are present in the diet. Together they comprise approximately 1/3 of human muscle tissue. All top quality protein sources will supply all 9 essential amino acids. Amino acids are the building blocks of protein, which has been shown to increase lean muscle mass. BCAA’s have long been popular with athletes from a variety of sectors, involving strength and power, along with endurance and stamina. BCAA supplements are convenient to use and should be taken around the training window for maximum effect. PhD recommends using BCAA’s before, during and after intense exercise.