Creatine

Creatine is a nitrogenous organic acid that helps supply energy to all cells in the body, especially muscle. It increases the formation of ATP. It is produced from the amino acids glycine and arginine. Creatine can also be synthesized in the brain and can cross the blood-brain barrier via specific creatine transporters. In the brain, it plays a major role in ATP/ADP balance by providing a steady phosphorous group to ADP to replenish ATP. In addition to an energy substrate, creatine can be released from neurons and function as a neurotransmitter.

Creatine is metabolized to creatinine and excreted in the urine. Raised urinary creatine excretion was found in two, separate outbreaks of myalgic encephalomyelitis in New York State in 1950 and in 1961. Creatine was high during periods of relapse and normal during periods of recovery.

A 16-week double-blind, randomized control study in fibromyalgia patients showed creatine supplementation increased intramuscular phosphorylcreatine content by ~80% and improved lower- and upper-body muscle function, with some additional positive effects on general symptoms.

Supplement Safety
The International Society of Sport Nutrition has stated that creatine supplementation up to 30 g/day for 5 years is safe and well-tolerated in healthy individuals and in a number of patient populations ranging from infants to the elderly.