30 Servings Found naturally in watermelon, use L-Citrulline to increase blood flow, improve endurance, and reduce muscle soreness. L-citrulline increases natural arginine production to increase blood flow and oxygen to the muscles. An amino acid found naturally in watermelon, L-citrulline boosts arginine production to incerase nitric oxide and widen blood vessels. A well known vasodilator, L-citrulline increases blood flow and oxygen to the muscles benefiting endurance, performance, and recovery. Studies also show that L-citrulline has positive effects on the liver and helps to prevent the breakdown of other amino acids - which may have a positive effect on protein synthesis. Supplement with 3g per day.