Creatine is a safe, well-studied supplement. Studies in a variety of people have shown no detrimental health effects of taking creatine supplements in doses up to 4–20 grams per day for 10 months to 5 years ( 19 , 20 , 21 ).

Is it OK to take creatine?

Creatine is a relatively safe supplement with few side effects reported. However, you should keep in mind that: If you take creatine supplements, you may gain weight because of water retention in your body's muscles.

Who should not take creatine?

Creatine isn't recommended for people with kidney or liver disease, or diabetes. Others who should avoid taking it are children under age 18 and women who are pregnant or nursing.