Science-Based Nutrition Kq - Kyowa Quality Helps Improve Circulation and Muscle Maintenance Dietary Supplement Nutrition / 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 relive muscle fatigue Vascular health