The article reviews current literature on the biological role of carnosine, its properties and use as a supplement in periods of intense physical activity. Studies carried out on laboratory animals and humans have shown that carnosine can have a beneficial influence on the organism. Carnosine is found naturally mainly in the skeletal muscles, central nervous system, olfactory neurons and in the lens of the eye in some vertebrates, including humans. Due to its antioxidant, protective, chelating, anti-glycation activity, this dipeptide can be used to prevent and treat diseases such as diabetes, neurodegenerative diseases, diseases of the sense organs and cancers. It may also cure or alleviate many other disorders thanks to its wide spectrum of activity. Carnosine is already used by athletes to achieve better results, due to its buffering feature, which contributes to the maintenance of the acid-base balance in the muscles. Future studies on the influence of carnosine on the human organism may lead to the therapeutic use of this dipeptide for many diseases, in addition to improving both amateur and professional athletes' results.