creatine

After she moved to Albert Einstein College of Medicine in New York City, Daly extensively studied hypertension and later analyzed how muscle cells use creatine to produce energy.

Studies where two groups, one getting creatine and one a placebo, work out exactly the same amount—such that neither group is pushing themselves to the limit—show that the creatine doesn’t give you bigger muscles if you don’t put in extra work.

Muscles with stored creatine can rip a group from there and attach it to the ADP lying around—and voila, you have more ATP to use.

At this point, protein and creatine are the only two that I really feel comfortable recommending.

There are some other suggestions in there, like creatine and beta-alanine.

Creatine and creatinine also seem to lessen in amount, but of the extent of this change I am not as yet fully informed.

In vertebrates, the basis for the phosphoric acid is creatine, whereas invertebrates have arginine instead.