Methylpropionic acid (RSR13) is an allosteric hemoglobin modifier to which it binds in a non-covalent manner, reducing its affinity to oxygen in a dose-dependent fashion, and consequently, increasing peripheral oxygenation. The purpose of this article is to briefly present scientific evidence concerning pharmacological and functional characteristics, medical indications, and adverse effects of RSR13 use by athletes, the most recent alternative to enhance performance artificially. Preliminary experimental studies have verified some positive effect of RSR13 on the recovery of ischemic myocardium and on the extension of cerebral ischemia. However, the main indications currently under study are surgery with hypothermia and cardioplegia during extra-corporeal circulation and the use as a radiotherapy enhancing agent for certain solid tumors. One single study with a canine model has shown increased maximal oxygen consumption in isolated muscles, there existing no evidence that RSR13 can effectively enhance performance in humans. Actually, adverse effects such as reduced blood perfusion, increased arterial blood pressure, and impaired renal function have been described. As an anticipation of the potential increased use of RSR13 by athletes, methods have been developed for its detection in human urine samples.
Athlete; Doping; Muscle contraction; Oxygen consumption; Performance