Citrulline is non-protein amino and not found in abundance in "normal" diets. The highest natural content of citrulline can be found in watermelons. Citrulline is bonded in a 2:1 ratio with Malic Acid to form Citrulline Malate. It is one of the most overlooked and under dosed supplements in the industry and only recently moved into the spotlight. It is a great supplement for muscle endurance and very popular for enhancing muscle pumps when used at higher doses (3-6 grams). Raw Citrulline Malate mixes easily into any beverage and has a slight tart taste to it due to the Malic Acid bond.