All I got is that I've tried 20-30 gram single doses of creatine. The influencers say megadoses of it can help mental performance after not getting much sleep. Some Novorapid insulin to help dispose of it in the muscles LOL. Only did a few times so can't evaluate yet. I did read Milos had his athletes use 80 or 100 grams of it a day LOL. I never considered higher doses, though I remember Poliquin saying 40 grams a day and 20 grams on maintenance mode LOL, and this was when it was just introduced to the market.
I did see some peptide company selling lyophilized phosphocreatine to be used before workouts but the dose was in the milligrams. I just remembered that the Bulgarian company that made Tribestan had a product called Energix and I remember it was a vial and the cap held phosphocreatine powder to be dumped in the solution before drinking it.