Although the body can synthesize L-arginine, exogenous supplementation may be sometimes necessary, especially in particular conditions which results in depleted endogenous source. Among diseases and states when exogenous supplementation may be necessary are: burns, severe wounds, infections, insufficient circulation, intensive physical activity or sterility. In recent time, the attention was paid to the use of L-arginine supplementation by athletes during intensive sport activity, to enhance tissue growth and general performance, to potentiate the ergogenic potential and muscle tolerance to high intensive work and gas exchange threshold, to decrease ammonia liberation and recovery performance period and to improve wound healing. High-intensity exercise produces transient hyperammoniemia, presumably due to AMP catabolism. Catabolic pathways of AMP may involve its deamination or dephosphorylation, mainly in order to compensate fall in adenylate enrgy charge (AEC), due to AMP rise. The enzymes of purine metabolism have been documented to be particularly sensitive to the effect of dietary L-arginine supplementation. L-arginine supplementation leads to redirection of AMP deamination on account of increased AMP dephosphorylation and subsequent adenosine production and may increase ATP regeneration via activation of AMP kinase (AMPK) pathway. The central role of AMPK in regulating cellular ATP regeneration, makes this enzyme as a central control point in energy homeostasis. The effects of L-arginine supplementation on energy expenditure were successful independently of age or previous disease, in young sport active, elderly, older population and patients with angina pectoris.