A new UNSW study challenges the widely held belief that creatine supplements enhance muscle growth when combined with resistance training.
The randomised control clinical trial published in Nutrients found no difference in muscle gains between participants who took creatine and those who did not.
The 12-week study involved 54 adults who completed a supervised resistance training program.
Both groups gained an average of 2kg of lean body mass, regardless of creatine use.
“We’ve shown that taking 5g of creatine supplement per day does not make any difference to the amount of lean muscle mass people put on while resistance training,” says senior author Dr Mandy Hagstrom, from UNSW’s School of Health Sciences.
“The benefits of creatine may have been overestimated in the past, due to methodological problems with previous studies,” she adds.
What is creatine?
Creatine is a naturally occurring compound which supplies energy to muscles.
It is produced by the liver, pancreas and kidneys, and found in protein-rich foods.
Previous research shows creatine supplements help build muscles, enhance athletic performance, and may even have cognitive benefits.
However, previous trials have started supplementation and exercise programs on the same day, making it difficult to separate the effect of each on muscle gains, according to Dr Hagstrom.
They’ve also overlooked the potential for creatine to cause water retention, though more research is needed to confirm this.
In this trial, those in the supplement group started on creatine one week before the exercise program began, taking 5g per day, which is at the upper end of the recommended maintenance dose of 3-5 grams.
“We had what we call a wash-in phase, where half of the participants started taking the supplement, without changing anything else in their daily life, to give their body a chance to stabilise in terms of its response to the supplement,” says Dr Hagstrom.
The effect of creatine with and without resistance training
During that first week of this trial people taking creatine gained more lean body mass, particularly women, gaining an average of 0.5 kilograms more than the control group.
However, the extra gains they made varied greatly, and soon dropped back to match those of the control group.
“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,” says Dr Hagstrom.
“Then once they started exercising, they saw no additional benefit from creatine which suggests that 5g per day is not enough if you’re taking it for the purposes of building muscle.”
By comparison, previous trials with no wash-in period found those on creatine gained one kilogram more muscle, than those not taking the supplement, during trials spanning four to 12 weeks.
More research needed on creatine doses
The trial suggests people need to take more creatine than is commonly thought to get the desired benefit of additional muscle gains, the experts say.
Just how much more will need to be the subject of further research, but 10g could be the dose to test first, given it’s already shown to be safe and promising for both brain and bone health, according to Dr Hagstrom.
A longer study would also be beneficial, says first author Dr Imtiaz Desai, from UNSW’s School of Health Sciences and Neuroscience Research Australia (NeuRA), as would measuring body water content, tracking the menstrual cycle – which can affect fluid retention – and creatine absorption, which was not feasible for this trial.
“It would be really interesting to see if creatine has more of a long-term benefit,” says Dr Desai.
“When you start weight training, you have those beginner gains in strength and those start tapering off around the 12-week mark and become slower, so it’s possible the support from creatine might come at a later stage.”
More realistic expectations on creatine use
The researchers hope the current study will give people more realistic expectations on creatine use, and prompt them to question claims made in the marketing of some supplements.
“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,” says Dr Desai said.
“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.”
As for researchers, it’s hoped the study may encourage others to start to use a wash-in phase, to better understand the impact of supplements with and without exercise.
