While many fitness supplements have come and gone due to their lack of efficacy or safety, one remains intact and popular—creatine monohydrate, or creatine for short. It’s a naturally occurring compound produced by the liver, pancreas and kidneys that supplies energy to muscles. Creatine is also found in protein-rich foods, such as meat, poultry and fish, while plant-based foods contain little to no creatine.

You can also supplement with creatine, which is popular with fitness enthusiasts, bodybuilders and athletes. Previous research shows creatine supplements help build muscles, enhance athletic performance and may even have cognitive benefits.

But much of the research on creatine and resistance training starts supplementation and the exercise program on the same day, making it difficult to separate the effects of each on muscle gains. Researchers from Australia wanted to see if creatine supplementation alone, before starting an exercise program, had any effects on lean body mass compared to a control group who did not take creatine. 

In addition, they wanted to know if this “wash-in phase” had any effect on muscle mass when a resistance training program was added. They published their findings in a recent study in Nutrients. Let’s break down what they found.

How Was This Study Conducted?

Sixty-three participants with no known medical conditions took part in the study—their ages ranged from 18 to 50, and all of them had a BMI of 30 kg/m2 or less. None of the participants had been engaging in the minimum amount of recommended physical activity—at least 150 minutes of moderate-intensity exercise per week—and none of them had done resistance training in the last 12 months. In addition, the researchers did not include anyone who used creatine supplements or antibiotics in the eight weeks before the study started.

Assessments were conducted three times: baseline (T1), after the “wash-in” phase (T2), and post 12-week resistance training (T3). The wash-in phase was a weeklong period when participants supplemented with creatine but didn’t do any resistance training. The assessments included body composition measurements, physical activity screening using a validated tool and self-reported diet and physical activity logs.

Participants were randomly split into two groups. One group received creatine supplements, while the control group did not. During the “wash-in” phase, the creatine group took 5 grams of pure, unsweetened creatine a day dissolved in water for seven days. During this time, neither group exercised. 

During the second phase, which lasted 12 weeks, the creatine group continued taking 5 grams of creatine a day, which is the upper level of the recommended maintenance dose for someone who is taking creatine regularly. During this phase, both groups also started the same supervised resistance training program three times a week.

The resistance training included a full-body resistance training program supervised by exercise physiologists. Participants completed four sets of six to 12 repetition-maximums, with 60 and 120 seconds of rest between sets and exercises, respectively. Repetition-max is a way to individualize the intensity of resistance training exercises. The last repetition of each set should be difficult to perform, which means the amount of resistance used is tailored to each person.

What Did This Study Find?

After running several statistical analyses, several findings surfaced. They included:

• At baseline and after the wash-in period (T1 and T2), there was a significant difference between the two groups for changes in total lean body mass, favoring the supplement group—an average change of 0.51 kg in lean body mass in the creatine group.
• In the creatine supplementation group, female participants showed a greater change in lean body mass than the men, with a 0.55 kg change in lean body mass. 
• Following the 12-week resistance training intervention (from T2 to T3), both the control group and the creatine group gained about 2 kg of total lean body mass. 
• From baseline to the end of the study (from T1 to T3), there was a significant difference between groups for changes in total lean body mass, favoring the supplement group (2.78 kg vs. 2.04 kg). But there were no differences between the groups regarding changes in fat mass.
• For female participants specifically, those in the supplement group gained more lean body mass (2.6 kg vs. 1.4 kg).

Overall, researchers concluded that their results demonstrate that a week of creatine supplementation without resistance training led to a significant difference in lean body mass between groups. But they also suggest that when a supplement wash-in period is used prior to starting a resistance-training program, 5 grams of creatine per day for 12 weeks did not increase lean body mass more than resistance training alone.

How Does This Apply to Real Life?

Studies on creatine supplementation have been mixed—and they measure different outcomes, so it’s sometimes difficult to compare. For example, a systematic review and meta-analysis of 23 studies on muscle strength gains in adults under 50 years old suggests that participants who took creatine while resistance training experienced greater upper and lower body strength gains compared to participants taking a placebo. That review suggests that supplementing with creatine can result in significant strength gains, but it doesn’t say anything about muscle mass—though if you’re gaining strength, you’re probably also gaining some mass. 

According to Mandy Hagstrom, Ph.D., one of the study authors for this current study, the gains the creatine group experienced after taking creatine for the seven days prior to starting the resistance training might not have been from an increase in muscle mass. 

“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 Hagstrom in a press release. “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.” 

Hagstrom states that more research is needed to sort out what dose of creatine is safely the most effective, and she adds that 10 grams per day may be a good place to start, since this dose has already been shown to be safe to take regularly. Imtiaz Desai, a Ph.D. candidate and one of the study’s authors, adds that a longer study that also measured body water content and creatine absorption and tracked menstrual cycles of female participants would also be beneficial.

If you were to start supplementing with creatine, the typical recommendation is to begin with a loading phase. This includes taking 20 to 25 grams of creatine daily for up to one week. There’s a caveat to this, though, as this sudden, intense amount can cause some unwanted side effects, including gastrointestinal upset. After the first week, the maintenance dose continues at 2 to 5 grams of creatine daily. We did the hard work for you and researched several creatine supplements and chose our top six picks. 

But creatine isn’t the only substance that will support building muscle mass. Eating enough calories in general is necessary to build muscle. And making sure you’re eating plenty of carbs (yes, we said carbs) and protein. Plus, foods with magnesium, omega-3s and vitamin D will also go a long way toward adding muscle to your frame. 

Of course, resistance training is also a must. But contrary to what many believe, you don’t have to join a gym to resistance train. To start, your body is a built-in gym, so begin with body-weight exercises—like squats, lunges, push-ups, dips and planks. If you want to use equipment, a set of dumbbells with varying sizes is a great place to start. Exercise bands are convenient and travel well. And a stability ball and weighted balls are bonuses that will help banish boredom and keep your progress moving forward. 

If you have no idea where to start, there are plenty of apps out there that can help—or hire a certified personal trainer. If you’re a social butterfly, you might enjoy group classes. You could even enlist the help of a friend who is experienced at resistance training. 

The Bottom Line

This study suggests that there was no major difference in lean body mass gains between a group that took creatine and did resistance training and a group that only engaged in resistance training without taking creatine. More research needs to be done to confirm those findings. 

If you currently resistance train and want to see if you can get more gains by adding creatine to your strategy, read the label and follow the directions. Before shelling out the money for it, though, assess your diet and make sure you’re getting enough muscle-building nutrients. And be sure that you’re switching your resistance training up by including a variety of exercises for all the muscle groups, as well as increasing the amount of resistance as you progress. 

Sleep and stress can also affect muscle growth, so be sure you’re honing in on those areas. And be sure you’re giving your muscles enough time between workouts to recover. Overtraining can have the opposite effect of what you’re going for.