Creatine is synthesized in the body, primarily in kidneys, liver, and pancreas, and can also be obtained exogenously through the diet (seafood, red meat, and poultry) or supplements. It is primarily stored in muscles, with a majority as phosphocreatine (PCr) and the rest as free creatine.

Supplementation with creatine has been shown to improve power, endurance, and strength in resistance training.

However, when it comes to endurance performance, the effects of creatine are less clear.

• Negative effects: some studies suggest that creatine may have a negative impact on endurance performance due to water retention and an increase in body mass.
• Positive effects: creatine supplementation can enhance glycogen resynthesis, buffering capacity, and reduce oxidative stress and inflammation, potentially improving endurance performance and recovery by countering the gains in body mass.

The effectiveness of creatine supplementation may depend on factors such as exercise intensity, anaerobic work capacity, and the recruitment of fast-twitch muscle fibres.

It seems to be more beneficial in high-intensity races or activities that involve bursts of high-intensity efforts. In continuous, steady-state moderate-intensity endurance exercise, creatine is unlikely to have a significant benefit.

Based on the current scientific evidence, recommendations for practical application of creatine supplementation include a loading phase followed by a maintenance dose.

Creatine monohydrate is the most researched form, and co-ingestion with carbohydrates may enhance its uptake. Response to creatine may vary among individuals, and it is advised to experiment with the supplementation during off-season periods.