Creatine, citrulline, betaine, beta-alanine, BCAAs—once upon a time, they were all single ingredients that athletes and lifters would take alongside their staple supps like protein or caffeine. Then, as the science—and the results—stacked up, they became staples. That’s happening right now with the powerful nootropic compound alpha glyceryl phosphoryl choline—alpha-GPC or A-GPC for short. …