Taking creatine supplements might help you think a little better and stay in a better mood when you're tired from not sleeping enough, especially if you're also doing light exercise—based on two small studies.

During sleep deprivation, taking more creatine (0.35 g/kg) leads to slightly better cognitive performance than taking less (0.2 g/kg), but the benefit does not increase beyond a certain dose, suggesting the brain reaches a limit in how much creatine it can use under these conditions.

Taking 0.35 grams of creatine per kilogram of body weight during sleep deprivation improves cognitive performance, with the strongest effects occurring about 4 hours after taking it and lasting up to 9 hours, likely due to sustained changes in how the brain uses energy.

Taking creatine supplements may enhance thinking and memory in older people or those who are sleep-deprived or have cognitive difficulties, but it does not noticeably change thinking skills in healthy young adults.

Taking a specific dose of creatine monohydrate by mouth during a night of little sleep may help maintain faster thinking in language, logic, and math tasks, reduce feelings of tiredness, and help preserve normal energy-related chemistry in the brain.

Taking 0.2 grams of creatine monohydrate per kilogram of body weight as a single oral dose can reduce the decline in cognitive functions such as logical reasoning, numerical processing, language speed, and attention during 21 hours without sleep in healthy young adults.