Adenosine triphosphate is the immediate energy currency of cells. What that means is that all energy-producing nutrients eventually become ATP through processes within cells, specifically in their mitochondria. Some of the most popular sports food supplements, such as creatine, ribose and citrulline malate, aide the production of ATP in some way.
ATP produces energy by giving up one of its three phosphate groups through enzymatic action. The breaking of the actual phosphate bond is what produces the energy. Creatine comes into play because it donates a phosphate so that ATP can be rapidly regenerated. Ribose contributes to the physical structure of ATP, since ATP is classified as a purine nucleotide.
So the obvious question is, Why not cut to the biochemical chase and provide straight ATP supplements instead of accessory supplements such as creatine or ribose? One reason ATP supplements have not appeared on the market until recently is that ATP has a molecular weight of more than 500, so attempting to have a cell absorb an oral ATP supplement is tantamount to trying to squeeze an elephant through a keyhole. In contrast, creatine weighs a paltry 140 and is easily absorbed.
Furthermore, it must be absorbed intact to be effective. But the presence of phosphatase enzymes in the gut and in the blood makes that unlikely. As the name implies, phosphatase enzymes function by breaking off phosphate bonds. If the enzyme encounters ATP, it breaks off the phosphate bonds prematurely, leaving you with free adenosine and phosphate'and no energy. On the other hand, animal-based studies show that the phosphate and adenosine taken in concentrate in liver ATP pools, contributing to them by supplying raw material for ATP synthesis.
One possible way around those formidable problems is to allow ATP to bypass the enzymes that may degrade it. An enteric coating would let the ATP reach the intestines, where it could be absorbed intact.
A new study tested the idea that an enteric-coated ATP supplement may act as an ergogenic aid for exercise and athletic usage.1 Twenty-seven men were randomly assigned to a high-ATP group (225 milligrams), a low-ATP group (150 milligrams) or a placebo group. The study lasted 14 days. Subjects completed a Wingate anaerobic test to determine any changes in muscular power and a bench press test to determine any strength changes as a result of using the supplement.
None of the groups showed any significant changes in ATP blood levels. No changes occurred during the power test, but a few of the men taking the high-dose ATP demonstrated minor increases in muscular strength. The authors suggest that even high doses of ATP would be unlikely to affect strength or power, considering that the total body pool of ATP amounts to 80 grams. They also feel that the ATP molecule is just too large to be effectively absorbed through any oral route.
On the other hand, men who took the larger dose of ATP reported feeling better. That would be consistent with increased ATP uptake, since ATP positively affects several brain neurotransmitters known to control mood.
So do ATP supplements work or don't they? They did appear to work for a few of the participants, who showed some strength gains and reported feeling better. Clearly, the door isn't ready to close on ATP supplements just yet.
1 Jordan, A.N., et al. (2004). Effects of oral ATP supplementation on anaerobic power and muscular strength. Med Sci Sports Exerc. 36:983-990.