Creatine is a natural substance found in meat (particularly wild game) as well as fish (primarily herring, salmon and tuna). It is also made in the body, stored in our muscles and used for energy. It’s the building block for ATP (adenosine triphosphate), the high-energy compound that fuels muscles during short, high-intensity exercise such as weight training or sprinting. As ATP is consumed, muscles become fatigued.
The proposed rationale for taking supplemental creatine is that it helps delay exhaustion of ATP so you can work out harder and longer and recover faster. Creatine supplements are widely used among athletes including body builders, professional baseball and football players, and uncounted high school athletes. However, because we have no data showing that taking creatine supplements is safe and effective for young people, both the American College of Sports Medicine and the American Academy of Pediatrics advise against the use of creatine by anyone under age 18.
Be aware that not all human studies show that taking creatine supplements improves athletic performance. In addition, not everyone responds the same way to the supplements. You may not get the energy boost you seek if you already have high stores of creatine in your muscles. If the supplements do help you, once you stop taking them any gains are likely to vanish.
The latest review of this subject was published in 2017 in the Journal of the International Society of Sports Nutrition. It concluded that in addition to athletic and exercise improvement, creatine supplementation may enhance post-exercise recovery and help prevent or reduce the severity of injuries, including the risk of heat-related illness stemming from exercise in hot and humid conditions. It also noted that creatine supplementation has been investigated for treatment of a number of health problems, including neurodegenerative diseases, diabetes, osteoarthritis, fibromyalgia and others.
If you take creatine, you’re likely to absorb it better if you take it with fruits, fruit juice and starches. While you’re unlikely to develop side effects when taking the recommended doses (a maximum of five grams of creatine monohydrate, four times daily for two to five days per week for up to six months), the most common ones include weight gain, muscle cramps, muscle strains and pulls, stomach upset, diarrhea, and dizziness. More serious adverse effects may occur, including high blood pressure, liver dysfunction, and kidney damage.
Creatine supplements can interfere with medications used to control blood sugar and may increase the cholesterol-lowering effects of statin drugs. Avoid creatine supplements if you take diuretics. Using them with drugs such as Tagamet and ibuprofen that can affect the kidneys can potentially increase the risk of kidney damage. In addition, creatine may interact with certain antibiotics. Overall, if you’re taking any prescribed medication, ask your physician or pharmacist about any potential problems.
Andrew Weil, M.D.
Richard B. Kreider et al, “International Society of Sports Nutrition position stand: safety and efficacy of creatine supplementation in exercise, sport, and medicine,” Journal of the International Society of Sports Nutrition, June 13, 2017, doi.org/10.1186/s12970-0173-z