Walk into any gym or scroll through fitness forums or social media, and you’ll hear about creatine. It’s one of the most-studied—and hyped—supplements on the market. Weightlifters swear by it for boosting strength and muscle size. But what does the science say? And is creatine safe? Do some people benefit from it more than others? What about the claims that it improves memory?  

What is creatine and how does it work? 

Creatine is a compound that your body makes from a few amino acids (the building blocks of protein). Foods like meat, poultry, and fish contain a modest 1/2 gram or so in a 4 oz. serving. That means that people who eat those foods will likely have higher levels of creatine stored in their muscle than people who don’t. But takingcreatine supplements (a typical dose is on the order of 3 to 5 grams per day) is the most effective way to boost your muscles’ creatine reserves. 

Creatine’s primary role in muscles comes down to energy. When your muscles need energy, they rely on a molecule called ATP (adenosine triphosphate). ATP is the body’s primary energy source, but your muscles store only enough ATP to last a few seconds. That’s good for short, intense bursts of activity like sprinting or lifting weights. And that’s where creatine—which binds with phosphate in muscle cells to form phosphocreatine—comes in. Creatine acts like a cell’s backup battery, rapidly donating a phosphate to regenerate ATP, allowing your muscles to continue contracting for a few more seconds. So taking creatine may help you eke out a few more reps of bicep curls or push yourself faster in a sprint. And over time, that may help you develop more strength and lean mass. 

“Creatine also attracts water into the muscle,” says Brad Schoenfeld, professor of exercise science at Lehman College in New York City. “And cellular hydration is theorized to promote muscle development by increasing protein synthesis and decreasing protein breakdown.” 

Can creatine build bigger or stronger muscles? 

Creatine helps you work harder so that you can build bigger muscles. It does nothing if you’re not pairing it with a consistent strength-training regimen. (It also does nothing for aerobic activities like long-distance running, swimming, or cycling.) 

Just don’t expect to end up looking like a bodybuilder. In one analysis of roughly 30 studies, the combination of creatine supplements and resistance training led study volunteers to pack on about two pounds more of lean body mass than people who did resistance training and took a placebo. (Some of the authors of that analysis have received funding from companies that sell creatine.)  

If you’re looking to gain muscle, two pounds is a notable increase. “But lean mass is not necessarily muscle mass,” says Schoenfeld. Creatine can cause water retention, and that extra water gets counted as “lean body mass.”  

So Schoenfeld and his colleagues (some of whom have received funding from creatine companies) grouped together 10 studies that lasted for an average of roughly five months each. The studies directly imaged and measured the size of the participants’ muscles using techniques like ultrasound or computed tomography (CT scans) after the volunteers took creatine (or placebo) supplements and did resistance training. The impact on muscle size was tiny. On average, taking creatine while resistance training increased the thickness of upper- and lower-body muscles by roughly five hundredths of an inch compared to doing resistance training alone. 

Because the trials included in Schoenfeld’s analysis measured muscle size, and the other trials measured lean body mass, their findings can’t be compared. But Schoenfeld thinks the estimates of creatine’s impact on muscle growth may be a bit inflated. 

Muscle mass and size aside, creatine may help some people get a bit stronger, though the effects are generally pretty small. In an analysis (one coauthor reported ties to the creatine industry) that included a total of 69 studies, creatine takers were able to bench about three pounds more—and squat about 12 pounds more—than placebo takers.  

It’s also not clear who benefits most from taking creatine. Schoenfeld’s analysis found no benefit of creatine on muscle size in older adults, while other studies have. “It could be that there just aren’t enough studies in older adults using direct imaging to make good conclusions,” he says. “Maybe five years from now, we’ll have 10 more studies and can get a clearer picture.” 

Most studies also show less of a creatine-fueled boost in muscle size and strength in women.  

“And diet may make a difference,” says Schoenfeld. “Because creatine is found in meat, vegans and vegetarians tend to respond better to creatine supplementation because they have less in their bodies to start with.”  

Can creatine boost cognitive performance? 

The brain is one of the body’s most energy-demanding organs. And because creatine helps regenerate ATP (the energy “currency” of the cell), some researchers have looked at whether creatine can boost memory and cognitive performance. 

In 2024, the European Food Safety Authority (EFSA, the EU’s equivalent of the FDA) reviewed 23 studies to determine if creatine could boost memory or cognitive performance. In a few of the trials, working memory (the small amount of information that can be held in the mind just long enough to use it) improved in people who took 20 grams of creatine a day for about a week. But studies that used lower doses (between 2 and 14 grams of creatine a day) or lasted longer found no effect on working memory. And creatine had no impact on outcomes like alertness, attention, processing speed, or executive function (the ability to plan, remember instructions, and manage multiple tasks). EFSA concluded that “a cause-and-effect relationship has not been established between the consumption of creatine and an improvement in cognitive function.” 

Is creatine safe? 

Creatine is considered safe for most people. “I have not seen any good evidence of side effects that I would be wary of in healthy people,” says Schoenfeld.  

In one analysis of data collected from roughly 26,000 volunteers who participated in 685 creatine studies, the authors reported no differences between creatine takers and placebo takers in 35 side effects like muscle cramps, headaches, or GI issues like nausea or diarrhea. (The analysis was partly funded by creatine companies.) 

Creatine breaks down into a compound called creatinine, which is eliminated from the body through the kidneys. While the analysis found no signs of kidney problems in creatine takers, most of the volunteers in the 685 studies were young, healthy adults without kidney problems and the studies were, on average, just two months long.  

What’s more, “we don’t have, say, 10-year studies on creatine,” Schoenfeld points out. To be on the safe side, people with kidney disease should check with their doctor before taking creatine.

How should you take creatine?  

Interested in trying creatine? First, look for a brand that has received a third-party certification, like those described by the Department of Defense’s Operation Supplement Safety. That way, you can trust that the label matches what’s in the bottle. Some companies also ensure that there are no unsafe levels of contaminants and that the supplement is free from substances banned by major athletic organizations.  

While there are many chemical forms of creatine (like creatine monohydrate, creatine hydrochloride, creatine nitrate, or creatine bound to other ingredients), your best bet is to stick with creatine monohydrate. It’s the best-studied, and most research shows no better results from other forms.  

Creatine typically comes as a powder that you mix into water or another liquid, though it’s also available as chewable tablets or capsules. 

Just be wary of gummies. According to the supplement-rating app company SuppCo, which published testing results of creatine gummies this past June, “All creatine gummies we tested were bestsellers on Amazon.com, and four of the six failed our testing spectacularly, with almost no creatine whatsoever in them.” 

There are two main strategies for taking creatine supplements: 

1. Use a “loading phase,” where you take 20 to 25 grams per day (split into four or five doses taken throughout the day) for about a week. Then follow that with a maintenance phase of 3 to 5 grams per day.
2. Take a daily low dose of 3 to 5 grams with no loading phase. 

Neither approach is better than the other. “It only matters for expediency,” says Schoenfeld. “A loading phase is advisable if you want to get your creatine stores fuller, faster.” Without a loading phase, it can take about a month to achieve what you otherwise can in about a week, he points out. “But a loading phase is kind of a pain,” adds Schoenfeld. “You can get more incidents of gut distress.” 

If you’re using creatine powder, mix it in water or another liquid. Creatine breaks down in water, but unlike what some people claim, you don’t need to drink it immediately after mixing. Creatine degrades faster at higher temperatures and in more acidic solutions (so you might not want to mix it into, say, orange juice), but it’s fairly stable for about 8 hours when mixed into a liquid with a neutral pH, like water or milk. (That’s why you’ll find few—if any—bottled drinks that contain creatine.) 

Bottom line 

“If your goal is to maximize muscle growth, you could consider giving creatine a try,” says Schoenfeld. “But the gains you get will be modest. Whether that’s meaningful is up to the individual.”  

Creatine is far from a magic bullet, nor does it work for everyone. “Think of it this way,” Schoenfeld offers. “Creatine would be the cherry on top of the sundae where the sundae is your training, nutrition, recovery, and sleep. It doesn’t add a whole lot.”