Abstract
L-Arginine is a semi-essential amino acid involved in numerous areas of human physiology, including production of nitric oxide (NO) – a key messenger molecule involved in vascular regulation, immune activity, and endocrine function. Arginine is also involved in protein production, wound healing, erectile function, and fertility. Arginine is not considered essential because humans can synthesize it de novo from glutamine, glutamate, and pro- line. However, dietary intake remains the primary determinant of plasma arginine levels, since the rate of arginine biosynthesis does not compensate for depletion or inadequate supply.1,2 Arginine is the most abundant nitrogen carrier in humans, containing four nitrogen atoms per molecule. Arginine is not a major inter-organ nitrogen shuttle; instead, it plays an important role in nitrogen metabolism and ammonia detoxification as an intermediate in the urea cycle.3