When shopping for a supplemental BCAA source look for a ratio of 76% leucine, 12% Valine, and 12% iso-leucine. The higher level of leucine is necessary because during high intensity activities, leucine is depleted quickly. Its by-products are used to create another amino acid called Alanine which in turn is metabolized into glucose in the liver for energy needs... ATP. (Oh ya, that stuff)
An interesting side bar about this 76-12-12% ratio is that athletes experience significant loss of visceral fat when using it. Visceral fat is the fat located in deeper layers of the body under subcutaneous fat stores. (Wow.)
Women especially experience difficulty when attempting to lose fat in these areas. As to daily dosage, 1 gram per 20 lbs of body weight of the 76-12-12% ratio in supplemental form is effective.