AICAR (5-aminoimidazole-4-carboxamide-1-β-D-ribofuranoside, 5-aminoimidazole-4-carboxamide ribonucleoside, acadesine) is each of several interesting things. First, it’s an important pharmacological research agent, used principally as an AMPK activator. It’s a compound which has shown extremely impressive fat-loss and endurance-enhancing effects in laboratory animals. Further, it has considerable mystique resulting from at least some use by elite European cyclists. And lastly, it’s readily available from research chemical sites and is being personally tried by many, though generally as part of stacks and combined with changes in training and/or diet.
Mechanism of Action
AICAR’s principal mechanism of action is activation of AMPK (AMP-activated protein kinase.) As is well known, ATP (adenosine triphosphate) is produced by mitochondria as a ready-to-use energy source for biochemical processes in the cell. These processes do not use glucose, fats, or fatty acids directly as energy sources: these must first be metabolized in the mitochondria to yield ATP. When ATP is used for energy, its first product is ADP (adenosine di-phosphate), and then – if the cell is really deprived of immediate sources of energy – finally to AMP (adenosine monophosphate.)
AICAR, at sufficient and quite substantial concentration, is effective at activating AMPK and inducing a cellular state as if exercise had been performed, or energy stores were low and fat therefore needed to be burned.
Reputed Dosage in Elite Cycling
I do not myself have a direct example known to me personally, but reputedly typical dosage has been about 500 mg/day for about four weeks prior to an event. This is lower than human-equivalent from animal research studies, but not so much so as to strain credulity. (In contrast, for example only 50 mg per day instead of 500 mg absolutely does strain credulity, let alone the 10 mg doses used by some as part of their stacks.)
How to use AICAR
In general I would recommend against using AICAR, but if wishing to do so anyway, I would use 500 mg/day for a limited period of time such as 4 weeks. For almost all persons this would be financially impractical with 50 mg pre-prepared vials.