Several toxicity tests have scientifically proven that creatine is neither acute nor subacutely toxic.
At the dawn of the "creatine era" supplies of 20 g per day during the loading phase and 5-10 g during the maintaining phase were recommended. Examinations of liver and renal function provided no indications of damage. By now there is no proof of a particular benefit from such high dosages. 10 g per day over 8 days and a maintaining dosage of 5 g per day are absolutely sufficient. For reasons of precaution, a short-time intake is recommended.
From "Deutsche Lebensmittel-Rundschau"
Over 300 clinic examinations explore its effects and toxicity.
Provided high-purity creatine monohydrate is used in foods for particular nutritional uses, the Panel considers that the consumption of doses of up to 3g/day of supplemental creatine, similar to the daily turnover rate of creatine, is unlikely to pose any risk.
So far, only for caffeine and creatine, there is scientific data to show that they have an ergogenic effect
Up to now, there are well-defined, scientifically proven, and performance-enhancing effects for caffeine and creatine.