IT DOES: Yes, Creatine Can Cause Weight Gain. This is How Much Is From Muscle Vs. Fat Mass.

The scale may tick up after you start taking creatine because the supplement can increase the total amount of water in the human body, explains Aubrey Grant, MD, director of sports and performance cardiology at MedStar Health in Washington, D.C. “This happens because creatine is stored in skeletal muscle, where it pulls water into the muscle cells through osmotic effects,” he says.

The result is usually a 1- to 3-pound weight gain in the first week or two of supplementation. “It is a predictable physiological response, and for most users, it is not harmful,” Dr. Grant says.

Again, he emphasizes that the extra pounds is not from fat.

Good to know.