What is creatine?
Creatine is an amino acid made in the liver and stored in muscles. When combined with phosphate, it is a readily available source of energy in the body. In the diet, creatine is present in milk, red meat, and some fish.
What claims are made about creatine?
People take supplements of creatine to improve physical or athletic performance and to decrease muscle fatigue. Creatine is used medically to improve physical functioning in people with certain muscle disorders or osteoarthritis.
Does creatine work?
Some studies indicate that creatine can increase the amount of work performed with a short maximal effort (for example, in sprinting).
What are the possible side effects of creatine?
Creatine supplements may cause weight gain and may elevate levels of creatine in the urine and blood and cause kidney dysfunction. Minor stomach upset, headache, dehydration, irritability and aggression, edema, and muscle cramps occur occasionally.
What drug interactions occur with creatine?
No drug interactions have been well-documented but doctors are concerned that taking creatine may increase the risk from drugs, such as nonsteroidal anti-inflammatory drugs (NSAIDs), that can affect kidney function. Also, caffeine may decrease the benefit of creatine by decreasing its energy production.
Creatine may be a slight help to athletes who need sudden bursts of power but the effects are unlikely to be large. It appears reasonably safe but people who have a history of kidney dysfunction or who are taking drugs that affect kidney function should avoid creatine supplements.