What Does Creatine Do?

Creatine helps your muscles quickly recycle energy during short, intense efforts like heavy lifts, sprints, and jumps. Topping up your muscle creatine with a supplement lets you squeeze out a bit more work in each session, and over weeks of training that adds up to more strength and muscle. Research also links it to some brain benefits.

It's one of the most studied supplements in sports nutrition, with hundreds of trials behind it. Below is what creatine does in your body, what it does for performance, muscle, and the brain, and just as important, what it doesn't do.

How Does Creatine Work in Your Muscles?

Your muscles store creatine mostly as phosphocreatine, a quick energy reserve. During a hard effort, phosphocreatine rapidly regenerates ATP, the molecule your muscles burn for power. More stored creatine means that system lasts a little longer before fatigue sets in, which matters most in the first seconds of all-out work.

The International Society of Sports Nutrition (ISSN) position stand on creatine explains that energy released from phosphocreatine "can be used as a buffer to resynthesize ATP." It also notes that a normal diet with 1 to 2 g of creatine a day leaves muscle stores only about 60 to 80% full, and that about 1 to 2% of muscle creatine breaks down each day. Plant-based lifters start even lower, which is covered in is creatine vegan.

A supplement closes that gap. A 2021 review of common creatine questions in the Journal of the International Society of Sports Nutrition reports that short-term loading raises muscle creatine stores by 20 to 40%. Once your stores are full, a small daily dose keeps them there.

How Does Creatine Help Strength and Muscle?

It helps you train a little harder, which leads to more strength and muscle over time. Studies show improved performance in repeated high-intensity efforts, and when combined with resistance training, extra lean mass compared with training alone. Creatine doesn't build muscle by itself. It makes your workouts slightly more productive.

The 2021 review reports that creatine loading improves exercise performance capacity by 5 to 10%. Over the longer term, a 2022 meta-analysis of 35 randomized trials found creatine plus resistance training increased lean body mass by about 1.1 kg more than placebo. Without exercise, the effect on lean mass was essentially zero.

Effect	How big the effect is	Source
Raises muscle creatine stores	20 to 40% after loading	2021 ISSN review
Improves high-intensity performance	About 5 to 10%	2021 ISSN review
Adds lean mass alongside resistance training	About 1.1 kg more than training alone	2022 meta-analysis
Adds lean mass without training	Essentially none	2022 meta-analysis

The scale may move before the muscle does, because creatine also draws some water into muscle. Our guide on whether creatine makes you gain weight explains the difference.

Does Creatine Help With Endurance?

Less than with strength and power. Creatine's main benefit is in short, repeated bursts of effort lasting about 30 seconds or less. A large meta-analysis found it didn't meaningfully improve running or swimming performance. It may still help with sprints, intervals, or surges within endurance sports.

A 2003 meta-analysis of 100 creatine studies found the biggest effects in repeated, high-intensity efforts of 30 seconds or less, especially in the lab and in upper-body exercise. It concluded that creatine "does not appear to be effective in improving running and swimming performance."

That fits how creatine works. Phosphocreatine powers the first seconds of hard effort, while longer endurance work relies mostly on other energy systems. If your sport is mostly steady cardio, creatine is less likely to make a big difference to performance. Runners have some specific trade-offs to weigh, covered in our guide on creatine for runners.

Can Creatine Help Your Brain?

It may modestly help memory, attention, and processing speed, especially in older adults and under stress like sleep loss. The brain uses a lot of energy and relies on creatine too. The evidence is promising but smaller and less consistent than the muscle research, so it isn't a proven brain booster yet.

A 2024 meta-analysis of 16 randomized trials in Frontiers in Nutrition found creatine improved memory, attention time, and processing speed, but not overall cognitive function or executive function. A 2023 meta-analysis in Nutrition Reviews found memory benefits in healthy people, with clearer effects in adults aged 66 to 76 than in younger people.

Researchers have also looked at creatine during sleep deprivation, with some encouraging early results. Our guide on taking creatine before bed covers those studies and their limits.

Does Creatine Help Women and Older Adults?

It appears to help both, especially when combined with resistance training. Older adults who take creatine while lifting gain more strength than those who lift alone. Women benefit too, though the average muscle gain in studies has been smaller than in men, and there's less research overall.

In a 2015 study of adults aged 50 to 71, creatine taken alongside 32 weeks of resistance training increased strength more than placebo, with extra lean tissue gains when taken after workouts. The 2021 ISSN review concluded that creatine plus resistance training "produces the vast majority of musculoskeletal and performance benefits in older adults."

For women, the same review found creatine "provides a variety of benefits for females across their lifespan." The 2022 meta-analysis found a smaller and statistically uncertain average lean mass gain in women than in men, so results may vary.

What Doesn't Creatine Do?

Knowing what creatine does also means knowing its limits. It doesn't act like a steroid or raise testosterone (here's what the hormone studies found), add body fat, or build muscle without training. Research also doesn't support common fears that it causes hair loss, kidney damage in healthy people, or dehydration. And it doesn't work instantly: its effects build over days to weeks as your muscle stores fill.

The 2021 ISSN review addressed the most common myths directly. It concluded that creatine "is not an anabolic steroid," "does not increase fat mass," does not cause kidney damage in healthy people at recommended doses, and does not cause dehydration or muscle cramping. It also found the majority of evidence doesn't support a link to hair loss, which a 2025 randomized trial later tested directly. Our guide on whether creatine causes hair loss covers that study, and the cramping trials are summarized in does creatine cause cramps.

If you have kidney disease, are pregnant, or take medication, talk to your doctor before taking creatine, since most research has been done in healthy people. Worried about your heart? See does creatine raise blood pressure.

How Should You Take Creatine to Get These Effects?

Take 3 to 5 g of creatine monohydrate every day, ideally alongside resistance training. Timing barely matters, so pick a time you'll stick with. You can skip a loading phase: daily doses fill your muscles in about three to four weeks. Consistency is what makes the effects show up.

The ISSN recommends 3 to 5 g a day to maintain full muscle stores, with larger athletes sometimes needing 5 to 10 g. For the details, see our guides on how long creatine takes to work, the best time to take creatine, and whether you need a loading phase.

Many people anchor their dose to their morning coffee. Iron Coffee has 5 g of creatine monohydrate in every serving, so the daily dose is built into the cup.