Citrulline is a non-essential amino acid that is an important intermediate in the urea cycle, functioning along with other amino acids to rid the body of ammonia, a byproduct of protein metabolism.

Citrulline also plays an important role in the healing process and in the maintenance of a healthy immune system. It also helps with waste disposal and clearing the body of the toxic by-products of exercise like ammonia.

Perhaps the most sought after benefit of citrulline is nitric oxide production to improve muscle pumps during exercise.