Science-Based Nutrition™ KQ - Kyowa Quality. Helps Improve Circulation and Muscle Maintenance. Dietary Supplement. Vegan / Non-GMO / Gluten Free / Soy Free. L-Citrulline is an amino acid that plays an important role in nitric oxide metabolism and regulation, which improves oxygen and blood circulation throughout the body. Research has shown that L-Citrulline raises plasma L-Arginine, thereby allowing higher protein synthesis and protein content in muscle during exercise. Supports Nitric oxide metabolism, Muscle protein synthesis and relieve muscle fatigue, Vascular health.