creatine-cortisol

In otherwise healthy men subject to sleep deprivation after 7 days of creatine loading, supplementation failed to have any effect when measured at 12-24 hours yet was able to improve executive functioning at 36 hours. Mood, cortisol, and memory were all still unaffected relative to placebo.

A week of creatine loading prior to sleep deprivation appears to not influence cortisol or serum catecholamines, but was associated with less reports of fatigue and more vigor relative to placebo. Despite the improved mood state, cognition during the 24 hours of testing was not significantly altered

Creatine loading in amateur athletes improved their swimming performance on a single 50-m sprint (by 4.6% relative to placebo) but failed to improve the 100-m sprint. When all hormones were measured in a rested state, neither growth hormone nor cortisol had changed significantly, but testosterone had increased by at least 15%.

In athletes who reported (retrospectively) creatine usage for up to four years, there was no significant adverse effect on healthy markers, although a nonsignificant trend to increase testosterone and decrease LDH (lactate dehydrogenase, a liver enzyme) was noted.