AICA ribonucleotide (AICAR) or 5-Aminoimidazole-4-carboxamide riboside acts as an AMP-activated protein kinase agonist. It stimulates glucose uptake and increases the activity of p38 mitogen-activated protein kinases α and β in skeletal muscle tissue,as well as suppressing apoptosis by reducing production of reactive oxygen compounds inside the cell.
In 2008, researchers at the Salk Institute discovered that AICAR injected in experimental mice significantly improves their performance in endurance-type exercise, apparently by converting fast-twitch muscle fibers to the more energy-efficient, fat-burning, slow-twitch type.
They also looked at the administration of GW 501516 (also called GW1516) in combination with AICAR. Given to mice that did not exercise, this combination activated 40% of the genes that were turned on when mice were given GW1516 and made to exercise. This suggests it may be possible to obtain some of the benefits of exercising without actually exercising.