AKA:Leucine, Isoleucine, Valine
The Mythology: Delays the onset of fatigue, allowing you to train harder. Like an amino acid version of Creatine. Muscles soak it up and grow huge when you take them post workout.
The Truth: Evidence for Fatigue improvement 50:50. No advantages over a pre or post workout protein shake.
Research: Amino acids are theorised to enhance performance in a variety of ways, such as increasing the secretion of anabolic hormones, modifying fuel use during exercise, preventing adverse effects of overtraining, and preventing mental fatigue.