Creatine acts as an energy buffer in the brain. It is converted into high-energy phosphocreatine in the body, which helps to create ATP. During times of activation the brain rapidly drains phosphocreatine to keep ATP levels constant. Oral supplementation of creatine has been shown to increase brain creatine levels between 3.5-13.3% with the average being about 8%. This additional buffer of energy may enhance performance on demanding tasks related to IQ. For healthy young well-rested omnivores, creatine does not seem to enhance function in other domains. For individuals who are sleep deprived creatine seems to consistently enhance executive function. Although vegetarians and vegans seem to respond best to creatine supplementation, vegetarians and omnivores have comparable baseline brain creatine levels.