I just take 5g/day with my morning coffee/water.
Rhonda Patrick has made several YouTube videos about creatine and you can find more information about creatine at her website - https://www.foundmyfitness.com/topics/creatine.
One of her creatine videos mentions that your muscles will take up ingested creatine faster than the brain. So for any creatine to make its way to the brain, your muscular creatine stores must be topped up first.
I think dosage would depend on the amount of daily physical activity. If you work out a lot, you'd have to replenish your muscular creatine stores before the brain could access any/much.
She also mentions boosting creatine dosage after bouts of mental exertion.
And an earlier 2018 article [2] argued that "Evidence suggests that the blood–brain barrier is an obstacle for circulating cre- atine, which may require larger doses and/or longer protocols to increase brain creatine as compared to muscle. In fact, the broad spectrum of creatine sup plementation studies that span different dosing pr- tocols (e.g. high-dose short-term, low dose longer- term), co-ingestion of other nutrients/compounds (e.g. carbohydrate, protein, insulin), different popu lations (e.g. vegetarians, elderly, patients, athletes) is unavailable for brain creatine adaptations"
1: https://www.nature.com/articles/s41598-024-54249-9
2: https://www.researchgate.net/profile/Bruno-Gualano/publicati...
This is probably an important difference from the average participant of those studies.
