NOBL BCAAs include three essential amino acids: valine, leucine and isoleucine - all of which have a branched chemical structure. The supplements typically supply twice as much leucine than isoleucine or valine, which is sometimes referred to as a 2:1:1 ratio. This is because leucine may be especially good at stimulating protein synthesis and suppressing the breakdown of muscle protein (1Trusted Source). All three BCAAs are directly taken up by your muscles rather than first being metabolized by your liver. As a result, BCAAs may have a faster effect. Directions of use: It may not make much difference whether BCAA supplements are taken before or after exercise, and you may not need to time them precisely to support muscle building. Best to take before/during/after training. Muscle-protective benefits of BCAA supplements may be more likely if you take 91 mg per pound (200 mg per kg) of body weight daily, including on non-exercise days. It may also help to split your daily BCAA supplement intake into two or more doses.