creatine is a critical part of our bodies energy system so it shouldn't be a huge shock, and cognitive benefits seem perfectly reasonable considering how dependent our brain is on effective energy pathways. When we expend energy, our body breaks down adenosine triphosphate (ATP) into diphosphate (ADP) and then eventually monophosphate (AMP) before finally just adenosine, but creatine-monophosphate can donate it's phospor when one is broken off in an energy transaction. Once AMP is converted to plain old adenosine it is shepherded off to the brain where it binds to the same receptors caffeine interferes with. When it binds you feel sleepy. I don't know, but it seems possible adenosine could be recycled in the brain more if there is enough creatine monophosphate around 🤷

Caffeine occupies the receptors and prevents adenosine from binding which prevents drowsiness. This is why after caffeine starts to wear off all of the energy you spent seemingly unaffected all of a sudden can have a toll.