Creatine is one of the most studied supplements.

It sounds you have the hardest part of it underway - consistency.

There's lots of studies - if you can get over 20g per day it is noticeable to the brain and energy. Adding a few grams a week until you're up there I found it noticeable. 20-30g seems to be a noticeable range.

Supplements aren't always like a coffee spike, they build up and sustain quite well.