Creatine Isn't Just for Muscles: What Else Does It Do?

This phosphocreatine system works very rapidly, which makes it particularly important during activities where your muscles suddenly need large amounts of energy but only for a relatively short period.

What does that mean during exercise?

Imagine you're performing a set of heavy squats. During the first few repetitions, your muscles need to produce a lot of force very quickly. Your available ATP is being used rapidly, while phosphocreatine helps replenish ATP so that high-intensity effort can continue for a little longer.

Creatine supplementation can increase the amount of creatine and phosphocreatine stored in skeletal muscle. With a larger phosphocreatine pool available, the muscles may be able to regenerate ATP more effectively during repeated bouts of high-intensity exercise.

Over time, this can support the ability to perform more training volume or maintain higher-intensity efforts, which can contribute to improvements in strength and lean mass when combined with appropriate resistance training.

This is an important distinction: creatine doesn't directly build muscle simply because you consume it. Rather, one of its major benefits is supporting the energy system that allows your muscles to perform repeated high-intensity work. Training itself, along with adequate nutrition and recovery, remains fundamental.

Your brain uses creatine too

Muscles may store most of the creatine in your body, but they aren't the only tissues that rely on it. Your brain also contains creatine and phosphocreatine, where they form part of an important system for maintaining cellular energy.

This matters because the brain is an energy-demanding organ. Even when you're sitting still, brain cells continuously require energy to support processes such as nerve signalling and communication between neurons. A 2022 review published in Nutrients describes creatine as an important component of brain bioenergetics, helping maintain the availability of ATP through the creatine-phosphocreatine system.

The basic principle is similar to what happens in your muscles:

Creatine → phosphocreatine → helps regenerate ATP → ATP becomes available for cellular processes

However, creatine metabolism in the brain isn't identical to what happens in skeletal muscle. The brain can synthesise some of its own creatine, and research suggests that increasing brain creatine concentrations through supplementation may be more difficult and variable than increasing creatine stores in muscle.

Still, creatine's established involvement in brain energy metabolism raises an interesting question: if creatine availability in the brain can be increased, could this influence how the brain performs?

Can creatine support memory and cognitive performance?

This question has led researchers to investigate creatine supplementation in relation to memory and other aspects of cognitive performance.

Memory is one of the areas with some of the more encouraging evidence. A systematic review and meta-analysis published in Nutrition Reviews examined randomised controlled trials involving healthy individuals and found that creatine supplementation was associated with an overall improvement in measures of memory compared with placebo. However, there was considerable variation between the studies, and the researchers emphasised the need for larger, longer-term trials.

Interestingly, the same analysis found that the improvement was more apparent among older adults aged 66–76 years, while a significant effect wasn't observed in the younger subgroup. That doesn't establish creatine as a treatment for age-related memory decline, but it does help explain why researchers are increasingly interested in creatine's potential relevance beyond younger athletes.

Research has also explored whether a person's usual dietary creatine intake could influence the response. Meat and seafood are major dietary sources of creatine, so people following vegetarian diets generally consume less preformed creatine. Earlier research has reported improvements in certain cognitive measures following creatine supplementation in vegetarians, although findings across the broader literature have been mixed.

Beyond memory, studies have examined areas such as attention, processing speed and executive function, but the evidence is less consistent. A 2018 systematic review of randomised controlled trials concluded that there was some evidence for improvements in certain cognitive measures, particularly memory and intelligence/reasoning, but the small number of studies and differences in their methods made firm conclusions difficult.

So, while the research is promising, creatine shouldn't be thought of as something that simply “makes you smarter”. Its effects on cognition appear to be more complex, and factors such as age, diet, baseline creatine levels and the particular cognitive task being measured may all be relevant.

What the research does demonstrate is that there is a genuine scientific basis for studying creatine beyond muscle. The brain uses the creatine-phosphocreatine system as part of its normal energy metabolism, and researchers are continuing to investigate whether increasing creatine availability could translate into meaningful cognitive benefits.

Creatine, mental fatigue and lack of sleep

One area where creatine's role in brain energy becomes particularly interesting is when the brain is placed under greater metabolic stress—such as during prolonged mental work or lack of sleep.

Sleep deprivation doesn't just make you feel tired. It can impair attention, reaction time, decision-making and other aspects of cognitive performance. Because creatine helps maintain ATP availability, researchers have questioned whether having greater creatine availability could help the brain cope when its energy demands are challenged. Reviews of the research suggest that creatine's cognitive effects may, in fact, be more noticeable under stressful conditions such as sleep deprivation than when someone is healthy and well rested.

Some of the earlier evidence came from studies in which participants took creatine for several days before being deprived of sleep. In one double-blind study, participants who supplemented with creatine for seven days showed less deterioration in choice reaction time, balance, mood and certain cognitive tasks after 24 hours of sleep deprivation compared with those taking a placebo.

More recent research has taken this further. A 2024 randomised, double-blind crossover study examined what happened when participants received a single high dose of creatine during 21 hours of sleep deprivation. Researchers observed changes in cerebral energy-related metabolites alongside improvements in cognitive performance and processing speed compared with placebo. However, the dose used—0.35 g per kilogram of body weight—was substantially higher than a typical everyday creatine serving, so the findings shouldn't be interpreted as a recommendation to take large doses when you're tired.

And importantly, the research base is still quite small. A 2026 systematic review identified only five studies examining creatine and acute sleep deprivation. While the overall findings showed a positive trend for certain cognitive and psychomotor outcomes, the authors concluded that more high-quality research is needed, and the effects may differ depending on the particular cognitive task being measured.

What about mental fatigue?

Researchers have also looked at creatine during mentally demanding tasks, even without complete sleep deprivation.

For example, studies have investigated whether creatine can help when people perform prolonged or repetitive cognitive tasks. Some findings suggest potential reductions in mental fatigue or improvements in particular measures of executive function, although the results haven't been consistent across all tests.

This fits with the broader theory behind creatine and the brain: its effects may become more noticeable when cellular energy demand is particularly high, rather than producing an obvious cognitive boost under normal everyday conditions.

That doesn't mean creatine should be viewed as a way to “power through” chronic sleep deprivation. Adequate sleep remains essential for cognitive and overall health, and creatine isn't a replacement for it.

Creatine and healthy ageing

Creatine's potential relevance isn't limited to athletes or younger adults. It has also become an area of interest in healthy ageing, particularly because maintaining muscle strength and physical function becomes increasingly important as we get older.

Ageing is naturally accompanied by changes in skeletal muscle. Over time, adults can experience reductions in muscle mass, strength and physical performance. More substantial age-related losses can contribute to sarcopenia, a condition characterised by declines in muscle strength, muscle mass and physical function. Sarcopenia can affect mobility and independence and is associated with a greater risk of falls, fractures and disability.

As we've already discussed, creatine helps muscles rapidly regenerate ATP, supporting the energy required for muscular contraction. Researchers have therefore investigated whether increasing muscle creatine stores could provide additional benefits for older adults, particularly when supplementation is combined with resistance training.

Creatine, strength and age-related muscle loss

The evidence is strongest when creatine is used alongside resistance exercise, rather than as a replacement for it.

A meta-analysis involving 22 studies and 721 older adults found that participants taking creatine while completing resistance training experienced greater increases in lean tissue mass and upper- and lower-body strength than those completing resistance training with a placebo.

More recent evidence continues to support this combination, although the size of the benefit can vary. A systematic review and meta-analysis published in 2025 found that creatine combined with resistance training improved lean tissue mass and lower-body strength compared with resistance training plus placebo, while the overall improvement in upper-body strength wasn't statistically significant. The researchers also highlighted limitations in the available studies and the need for larger, longer-term research.

This doesn't mean that creatine prevents ageing or that taking creatine alone will prevent sarcopenia. Resistance exercise itself has substantial evidence for improving muscle strength and physical performance in older adults, and maintaining muscle as we age also depends on factors such as adequate nutrition, physical activity and overall health. 

Instead, current research suggests that creatine may have a useful role as an addition to resistance training, potentially helping older adults achieve greater improvements in certain measures of muscle mass and strength than training alone.

And in the context of healthy ageing, those outcomes aren't simply about having bigger muscles. Maintaining enough strength to stand up from a chair, climb stairs, carry groceries and remain physically independent can become increasingly important later in life.

Conclusion: Creatine goes beyond muscle

Creatine may be best known for its place in the gym, but as we've seen throughout this article, its role in the body extends well beyond helping muscles perform during high-intensity exercise.

At its core, creatine is involved in cellular energy. Through the creatine-phosphocreatine system, it helps regenerate ATP so that cells can respond when energy is needed quickly. That process is particularly important in skeletal muscle, but it is also active in other energy-demanding tissues—including the brain.

This helps explain why creatine research has expanded into areas such as memory and cognitive performance, mental fatigue and sleep deprivation, and healthy ageing. Some findings are encouraging, however, reviews continue to emphasise that the evidence outside established exercise applications is still developing and isn't equally strong across every outcome or population. 

So, does this mean everyone should start taking creatine? Not necessarily. The fact that creatine has biological functions beyond muscle doesn't mean supplementation will provide the same benefit for every person. Diet, age, activity levels, health and the outcome you're hoping to achieve can all influence whether supplementation is relevant.

What it does mean is that it's time to move beyond the idea that creatine is simply a “bodybuilding supplement.” Its best-established benefits may have made it famous in sports nutrition, but its fundamental role is much broader: helping cells manage and rapidly replenish energy.