The BCAAs in whey are peptide-bound to other amino acids and, in order to be effective, must be liberated through digestion and then absorbed into the bloodstream. Even though whey protein is relatively fast digesting, it still takes several hours for all the amino acids to be liberated and absorbed into the bloodstream.
BCAAs in supplement form, however, are free-form, require no digestion, and are rapidly absorbed into the bloodstream. They spike blood amino acid levels to a much greater and faster extent than peptide-bound aminos. Even a few grams of free-form BCAAs will spike BCAA plasma levels to a much greater extent than 30 grams of whey protein, thereby having a more immediate impact on protein synthesis and protein degradation.
Additionally, since BCAAs bypass the liver and gut and go directly into your blood stream, they can be used as an immediate energy source during your workouts. Valine and isoleucine are considered glucogenic amino acids, meaning they can be converted to glucose and serve as an important energy source during exercise to help fight off fatigue during your workouts.
New studies have shown that dieting groups supplementing with BCAAs (like leucine) increase muscle retention and maximize fat loss much more effectively than non-supplemented groups. That's the bottom line, my friends: more muscle mass retained, and a greater percentage of lost body fat.
Forget other supplements that are long on promises but short on results. Instead, check out the power of BCAAs.