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Key Points
- Doctors say people should expect to see a 1 to 3 pound weight gain in the first week or two of taking creatine.
- Initially, the rapid weight gain comes from water retention. Creatine is stored in skeletal muscle where it pulls water into muscle cells.
- With strength training, the increased weight gain will be from muscle rather than water. Research finds people can gain about 2.51 pounds in lean muscle mass.
- There is no scientific evidence of creatine increasing fat mass.
Creatine is one of the most well-studied supplements, meaning doctors have a good grasp of its side effects. Weight gain is a well-known one, says Kristyen Tomcik, PhD, assistant professor of nutrition at the Case Western Reserve University School of Medicine. He says he experienced it personally during the first couple of weeks of going back on creatine after stopping the supplement for a while.
The problem is whether the extra pounds is muscle or fat mass. With creatine, Dr. Tomcik notes that weight gain isn’t happening in the most traditional sense.
The Number One Reason for Creatine Weight Gain
THE NUMBER ON 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.
Tomcik compares the water weight gain to what happens when you start a low-carb diet. Only in reverse. With creatine, your muscles hold more water. With low-carb diets, you often lose water weight at first because your body is depleting its stored carbohydrates, or glycogen, which hold water.
Water retention is most common during the early stages of taking creatine, Dr. Grant says. After a few weeks, the water weight gain tends to plateau. But it’s not completely gone.
“Some degree of increased intracellular water in the muscles will persist as long as creatine supplementation is continued,” Dr. Grant adds.
Weight Gain From Increased Muscle Mass
IF SOMEONE IS taking creatine and training hard, Dr. Grant says the weight gain is likely coming from actual increases in muscle mass, not just water weight. “That form of ‘weight gain’ is generally desirable.”
Creatine improves energy stores in the muscles, allowing for greater energy availability during short bursts of high-intensity activity, such as weightlifting or sprinting. It’s an indirect benefit. Tomcik says the little extra volume you do in the gym accumulates and usually translates to bigger gains. One research study found people taking creatine and lifted weights will gain about 2.51 pounds in lean muscle mass compared to people who only lifted weights.
OUR GUIDE TO THE BEST CREATINE SUPPLEMENTS
Does Creatine Increase Fat Mass?
IT’S A POPULAR misconception, especially if you’re seeing a higher body weight number. The answer, however, is no. A number of scientists have conducted clinical trials looking into this question have found the same answer. There was no change in fat mass when creatine was consumed short-term (7 days) versus a longer period (6 to 8 weeks and 1 to 2 years). There was also no difference in the fat percentages of people taking creatine and doing cardio versus strength training.
When To Be Concerned About Creatine Weight Gain
MOST CREATINE WATER weight is minimal and will level out over a few weeks, says Tomcik. “It’s not really anything to worry about.” Also, if you experience lean muscle gain, “that’s likely beneficial, especially for performance and metabolic health,” adds Dr. Grant.
The problem is when you’re pairing a creatine supplement with a poor diet or a lack of strength training. In that case, Dr. Grant says weight gain may come from increased fat mass. When using creatine, Dr. Grant recommends a structured resistance training routine, maintaining a balanced diet with adequate protein, and staying hydrated. As creatine increases muscle water content, so is the need to hydrate more.
If you’re going full on with a 20-gram-a-day loading dose of creatine and not feeling great or your weight is increasing, Tomcik suggests cutting back to 3 to 5 grams a day and increase the dosage slowly. Creatine supplements at 3 to 5 grams a day is safe for most men.
That said, creatine does have other side effects such as diarrhea, increase in blood pressure, and bloating. You’ll want to stop and reevaluate the dosage or creatine brand if it’s causing persistent health issues. Plus there is some debate on creatine causing kidney damage (recent research found no effect on the kidneys of healthy individuals). If you have kidney disease or at risk for it, talk to your doctor before starting the supplement.
“In general, for healthy men using creatine responsibly and paired with a solid training program, small increases in weight should not be a source of concern—they are often a marker of increased lean body mass and performance adaptation,” Dr. Grant says.
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Jocelyn Solis-Moreira, MS is the associate health & fitness for Men’s Health and has previously written for CNN, Scientific American, Popular Science, and National Geographic before joining the brand. When she’s not working, she’s doing circus arts or working towards the perfect pull-up.
Erica Sweeney is a writer who mostly covers health, wellness and careers. She has written for The New York Times, HuffPost, Teen Vogue, Parade, Money, Business Insider and many more.