The primary benefit of creatine is an improvement in strength and power output during resistance exercise. Creatine is well-researched for this purpose, and its effects are quite notable for a supplement, both in the general population,[1][2][3][4] and specifically in older adults.[5][6][7] When used in conjunction with resistance exercise, creatine may modestly increase lean mass.[2][7][6][8] In trained athletes, creatine has been reported to reduce body fat and improve some measures of anaerobic exercise performance, strength, and power output.[9][10] Creatine has also been tested for effects on anaerobic running capacity in many studies, the results of which are rather mixed but generally suggest a small improvement in performance.[11][12][13][14]
Although creatine has been researched far less for cognitive performance and mental health than for physical performance, it may have benefits in some contexts. Creatine appears to reduce mental fatigue in some scenarios, particularly highly stressful ones involving sleep deprivation or exercise to exhaustion.[15][16] Creatine may also improve some aspects of memory, particularly for people with below-average creatine levels, such as vegetarians and older adults.[17][18] There is also some preliminary evidence to suggest that creatine may reduce symptoms of depression in individuals with major depressive disorder or bipolar disorder.[19] That said, more research is needed in these areas and on other cognitive measures before creatine can be said to be effective for cognitive performance or mental health.