Creatine, a chemical constituent of meat and fish that’s legally been sold online, in supermarkets, health food stores and vitamin shops for at least a couple of decades, may be the most commonly used muscle-building supplement marketed.
But the safety and effectiveness of creatine hasn’t been rigorously analyzed by the Food and Drug Administration in the way that drugs are evaluated. And while proponents argue that the supplement’s long history of use by many athletes suggests it’s relatively safe for healthy adults, pediatricians warn that it’s unclear whether the supplement might harm the growing muscles and bones of kids and teens. That hasn’t been studied.
