Creatine is an amino acid located mostly in your body's muscles, as well as in the brain. Though it can be made synthetically, most people get creatine through seafood and red meat. The body's liver, pancreas and kidneys also make creatine.

Your body converts creatine to phosphocreatine and stores it in your muscles, where it's used for energy. As a result, people take creatine orally to improve athletic performance and increase muscle mass.

People also use oral creatine to treat certain brain disorders, congestive heart failure and other conditions. Topical creatine might be used to treat aging skin.

Research on creatine use for specific activities and conditions shows:

  • Exercise. A wide body of research on the impact of oral creatine use on exercise has produced mixed results. Oral creatine use might benefit athletes who require short bursts of energy, such as sprinters and weight lifters.
  • Rare creatine-metabolizing syndromes. In children with the certain creatine deficiency syndromes, oral creatine supplements might improve some symptoms.
  • Heart failure. There isn't enough evidence to recommend use of oral creatine as a heart failure treatment.
  • Skin aging. Preliminary research suggests that a cream containing creatine and other ingredients applied to the face every day for six weeks might reduce skin sag and wrinkles in men. Another study suggests that a cream containing creatine and folic acid improves sun damage and reduces wrinkles.

People who have low levels of creatine — such as vegetarians — appear to benefit most from creatine supplements.

Generally safe

Creatine might benefit athletes who need short bursts of speed or muscle, such as sprinters and weight lifters.

While taking creatine might not help all athletes, evidence suggests it generally won't hurt if taken as directed. However, people who have kidney disorders or people at risk of developing kidney disease should talk to a doctor before taking creatine due to concerns that the supplement might cause kidney damage.

When used orally at appropriate doses, creatine is likely safe to take for up to five years. However, there is concern that creatine taken in high doses is possibly unsafe and could damage the liver, kidneys or heart.

Creatine can cause:

  • Muscle cramping
  • Nausea
  • Diarrhea
  • Dizziness
  • Gastrointestinal pain
  • Dehydration
  • Weight gain
  • Water retention
  • Heat intolerance
  • Fever

Don't take creatine if you have a history of kidney disease or you have conditions such as diabetes that increase the risk of kidney problems. There also is some concern that creatine might increase mania in people who have bipolar disorder.

Many drugs might interact with creatine and increase the risk of kidney damage. Possible drug interactions include:

  • Nephrotoxic drugs. Because taking high doses of creatine might harm your kidneys, there is concern about combining creatine with drugs that might damage the kidneys (nephrotoxic drugs). Potentially nephrotoxic drugs include nonsteroidal anti-inflammatory drug (NSAIDs) such as ibuprofen (Advil, Motrin IB, others) and naproxen sodium (Aleve, others), cyclosporine (Neoral, Sandimmune) and others.
  • Caffeine and ephedra. Combining caffeine with creatine might decrease the efficacy of creatine. Combining caffeine with creatine and the supplement ephedra might increase the risk of serious side effects, such as stroke.
Oct. 12, 2017