Creatine Might Not Be the Muscle Miracle We Thought It Was

A common workout supplement might be less useful than believed. In research out this month, scientists found that creatine failed to help people build significantly more muscle than normal while training.

Researchers at the University of New South Wales led the study, published last week in the journal Nutrients. The clinical trial compared people who underwent resistance training while taking or not taking a typical daily dose of creatine, finding no significant difference in added lean body mass by the end; everyone gained mass while training—the scientists just didn’t see more mass in the creatine group as they expected. The findings could mean that larger regular doses of the supplement are needed to see muscle-building benefits, the researchers say.

Creatine is naturally produced by the body and can be found in certain foods such as seafood and red meat. It helps supply energy to the muscles, particularly during intense bursts of activity like lifting weights. Some research has suggested that creatine supplementation can help improve people’s athletic performance and their ability to pack on muscle mass, including in placebo-controlled trials (a gold standard of research).

According to the UNSW researchers, however, these past trials may have had a critical flaw, since they often had people start taking creatine just as they began their new exercise routine. This design means it would be harder to tell apart the separate benefits of creatine from exercise.

To get around this possible limitation, the researchers had some of their volunteers take creatine a week before the exercise part of the trial—a 12 week course of resistance training—began, which is known as a “wash-in” period. The volunteers took 5 grams of creatine a day, a dose often used for maintenance once people start taking it regularly (the researchers note that a loading phase is not needed to reach the saturation level of creatine, or the maximum amount of stored creatine that our bodies respond to). People in both groups were relatively healthy, but weren’t big exercisers prior to the study; in total, 54 people completed the trial.

The creatine group did seem to experience a small boost in lean body mass on average during the first week (around 0.5 kilograms). But these gains ultimately didn’t give people a leg-up over the controls; by the study’s end, both groups gained roughly two kilograms in added lean body mass on average.

“The people taking the creatine supplement saw changes before they even started exercising, which leads us to believe that it wasn’t actual real muscle growth, but potentially fluid retention,” said study researcher Mandy Hagstrom, an exercise scientist at UNSW’s School of Health Sciences, in a statement from the university. “Then once they started exercising, they saw no additional benefit from creatine, which suggests that five grams per day is not enough if you’re taking it for the purposes of building muscle.”

The findings don’t necessarily sink creatine as a muscle-building aid, the researchers say. It’s possible that over the longer term, for instance, people taking creatine could still experience greater muscle mass. Or it might take a higher maintenance dose to see these effects (the researchers note that 10 grams a day can be safe to take). The researchers also avoided using a “loading phase,” which is when people will start by taking a much higher dose of creatine at first, up to 25 grams, for the first week, but they did expect to see some effect from the dose they used in their study.

Ultimately, the researchers say more studies will be needed to test different doses and treatment lengths—studies that will hopefully incorporate wash-in periods and other measures to ensure accurate results. But the current findings may already help people keep their expectations in check if they decide to start taking creatine for muscle mass, they add.

“For your average person taking creatine to boost their gains in the gym, this will hopefully change their perception about what it can help them achieve,” said lead author Imtiaz Desai, from UNSW’s School of Health Sciences and Neuroscience Research Australia (NeuRA), in a statement. “For professional athletes, particularly those who must be at a particular weight for their sport, the findings may inform how and when they take the supplement.”