From the Manufacturer's Label:
Citrulline is a non-essential amino acid that is an important intermediate in the urea cycle, functioning along with Arginine and Ornithine to rid the body of ammonia, a byproduct of protein metabolism. Because Citrulline is a precursor of Arginine, it provides a readily available source material for Arginine production, thereby helping the body maintain healthy Arginine levels. Citrulline also plays an important role in the healing process and in the maintenance of a healthy immune system.**
Manufactured by NOW® Foods.Contains no sugar, salt, yeast, wheat, gluten, soy, milk, egg, shellfish or preservatives.