L-Arginine is one of the most popular supplements in bodybuilding, it plays an important role in muscle cell division, muscle recovery after training, injury healing, waste removal, immune system, and increases somatotropic hormone production. Arginine serves as a carrier and donor of nitrogen, which is essential in the synthesis of muscle tissue, and it is this function that has been the main factor in the spread of arginine in bodybuilding. Arginine promotes muscle mass gain and fat reduction with adequate exercise. The power to work the cycle (ornithine – citrulline – arginine) determines the body’s ability to create urea and clear protein slags. To gain muscle mass, arginine is recommended to be taken in doses from 5-9 g before training. The higher the dose, the more tangible the effect, but it is not recommended to exceed a dose of more than 10 g.