Creatine boosts your muscles, but its effects on your brain are more complicated than you might think.

Creatine does seem to help people get stronger and perform better in physical tasks like sprinting and jumping — that part checks out. But the idea that it has limited brain effects isn’t the whole story. Other research found that creatine helped people think more clearly when they were sleep-deprived, improving reaction time and logic. It also showed some benefit for people with depression when used alongside therapy or medication. So while it doesn’t make everyone sharper in everyday thinking, it does appear to influence the brain under certain conditions. As for the blood-brain barrier, there’s no research here to confirm or deny it as the reason for the difference.