The combination of these three amino acids make up over 1/3 of all skeletal muscle in the human body, and they have been shown to play an important role in protein synthesis, and thus muscle growth, repair and other vital cellular. Leucine can, amongst other benefits, promote exercise performance and recovery, especially when taken at high dosages. The refreshing and highly functional USN Amino Muscle has been developed to enhance your energy and performance levels throughout your workout, supporting a heightened output potential while speeding up recovery. L-Glutamine is the most abundant amino acid found in the human body and is arguably the most important in the process of building lean muscle and gaining strength.