NOW Sports Nutrition L-Citrulline Extra Strength offers a potent dose of this vital amino acid, formulated to support athletic performance and recovery. L-Citrulline is a non-essential amino acid that plays a key role in the urea cycle, helping the body to process and excrete nitrogenous waste. It is also a precursor to nitric oxide (NO), a compound that promotes vasodilation, leading to improved blood flow and oxygen delivery to muscles. This can translate to enhanced endurance, reduced fatigue, and better post-exercise recovery.