Creatine Explained: Benefits, Myths, Dosage, and What the Evidence Says

Creatine is one of the most studied dietary supplements. Once used mainly by athletes to improve muscle performance, it is now widely studied for potential benefits in muscle function, healthy aging, and cognitive performance. Here’s what creatine is, what it may help with, the potential risks, and how to take it.

What is creatine?

Creatine is a natural compound that helps your cells make energy. In muscle, it is converted into phosphocreatine, which helps produce ATP, the main energy source your cells use during movement.

Your body makes creatine in the kidneys and liver, and you also get it from foods like meat and fish or from supplements.

Without supplementation, about half of your creatine comes from what your body makes and about half comes from food. Recently published recommendations for daily intake to maintain optimal creatine status are 400 mg/day for men and 240 mg/day for women.1 For reference, a 6 oz serving of meat contains approximately 700 mg of creatine.

When it comes to creatine supplements, doses of 3 to 5 g/day are the best studied for muscle and performance outcomes, and these doses have also been shown to be safe. Although several forms of creatine are available on the market, almost all research to date has been done on creatine monohydrate, which is the recommended form for supplementation.

Creatine supplementation

Is creatine supplementation helpful for muscle function and performance?

Research shows that creatine monohydrate supplementation at doses of 3 to 5 g/day can increase muscle mass, strength, and power.2 These benefits appear strongest during short, repeated, high-intensity efforts such as sprinting or weight lifting. In simple terms, creatine may help you do a couple of extra reps or keep your power up during repeated hard efforts. The gains in muscle mass and strength that people experience when taking creatine is likely the result of being able to train harder over time.

Importantly, creatine works best when you are also engaging in resistance training, with studies of creatine supplementation showing little to no benefit in individuals who are not active.

The muscle and performance benefits of creatine monohydrate aren’t limited to athletes or young adults. In older adults (age 55+) who engage in resistance training, creatine can improve strength, muscle mass, daily function, and time to fatigue.3

It’s possible that people with lower baseline creatine levels, such as vegans and vegetarians, may respond especially well to creatine supplementation, although study results have been mixed.4

Does creatine supplementation support bone health?

The evidence is mixed. Some trials of creatine monohydrate (usually 5 g/day) in older adults have found small signs of benefit on bone mass and geometry when creatine is combined with resistance training. However, those benefits were not seen without resistance training. This suggests that exercise is likely an important part of any bone-related benefit.

Can creatine supplementation improve cognitive function?

There has been growing interest in creatine for brain health and cognitive function, especially because creatine helps cells produce energy. Researchers have been exploring whether raising creatine levels in the brain could support memory, attention, reasoning, and mental performance under stress.

For people who are healthy and well rested, the evidence is not especially strong. In adults who are not sleep deprived, large controlled trials have reported that creatine supplementation offers little or no meaningful improvement in overall cognition, reasoning, or similar mental tasks.5,6

The results are more promising in older adults. A systematic review looked at creatine supplementation or dietary creatine intake in adults age 55 and older, with cognition as an outcome.7 Five of the six included studies found positive associations between creatine and cognitive outcomes, especially in memory and attention. While this does not prove a clear cause-and-effect relationship, and more well-designed research studies are needed, it suggests that creatine supplementation may have potential in supporting healthy aging.

The strongest evidence for creatine and cognition so far appears to be in the setting of sleep deprivation. In one randomized controlled trial in young adults, taking 20 g/day for one week reduced declines in random movement generation, choice reaction time, balance, and mood after 24 hours without sleep.8 In rugby players, creatine at 50 or 100 mg/kg body weight (3.5 or 7 g for a 70kg man) helped reduce the drop in skill performance accuracy after only 3 to 5 hours of sleep, compared with a normal sleep period of 7 to 9 hours.9 In another study of young adults, a single high dose of creatine (0.35 g/kg, or about 25 grams for a 70 kg person) partially reversed changes in brain energy metabolism and improved vigilance, memory, and reasoning after 21 hours of sleep deprivation.10

Taken together, these studies suggest that creatine may be more useful when the brain is under short-term stress, rather than as a general cognitive enhancer. In other words, creatine may be most helpful when sleep is limited and mental performance needs extra support. Higher doses (e.g. 20 g/day) may be required to achieve these benefits–possibly because there are relatively few creatine transporters at the blood-brain barrier.

Overall, creatine and cognitive health is a promising area of research, but the evidence is still developing. The most promising findings are in older adults and in situations involving acute sleep deprivation, although more research is needed to confirm who is most likely to benefit, what dose works best, and whether the effects are meaningful over the long term.

Are there differences in how women and men respond to creatine supplementation?

In general, women appear to have lower baseline creatine stores than men, at roughly 70% to 80% of male levels.11,12 This has led researchers to ask whether women might respond differently to creatine supplementation.

So far, the answer is not fully clear. A recent meta-analysis looking at sex differences in creatine supplementation combined with resistance training found statistically significant strength gains in men, while effects in women did not always reach significance.13 However, that result should be interpreted carefully. Many studies included fewer women, and there was a lot of variation between study designs, training programs, and dosing approaches.

On the other hand, some women-specific randomized controlled trials do suggest that women can benefit from creatine, especially when it is paired with resistance training. In postmenopausal women, for example, a 12-month trial found that creatine supplementation during supervised resistance training improved relative bench press strength compared with placebo.14 A separate systematic review of older women found that creatine combined with resistance training significantly improved upper-body strength, and in longer studies, benefits were seen for both upper- and lower-body strength.15 These studies also found that creatine without resistance training did not lead to meaningful gains, which matches the broader creatine literature.

Some early evidence in perimenopausal and postmenopausal women suggests that creatine supplementation in these life stages may result in improvements in brain creatine levels, reaction time, mood-related symptoms, and lipid profiles with creatine supplementation. In an 8-week randomized, double-blind trial of 36 perimenopausal and postmenopausal women, supplementation with creatine hydrochloride resulted in faster reaction times, increases in frontal brain creatine levels, and improvements in lipid profiles compared to placebo.16 There was also a trend toward reduced mood-swing severity in women who received creatine hydrochloride. While these findings are promising, they should be viewed as exploratory rather than definitive at this time. The study was small, lasted only 8 weeks, and used creatine hydrochloride. It is not known whether the results are generalizable to other forms of creatine, such as creatine monohydrate, which is much better studied in terms of benefits and safety.

Another area that has drawn attention for potential sex-specific benefits of creatine supplementation is mental health. Some researchers have suggested that because females may have lower brain creatine levels, supplementation could potentially help with symptoms of depression. In an 8-week, double-blind randomized controlled trial, 52 women with major depressive disorder were assigned to receive either escitalopram (a SSRI medication) plus creatine monohydrate (5 g/day) or escitalopram plus placebo. The main outcome was change in scores on the Hamilton Depression Rating Scale (HAM-D). Women in the creatine group had a greater improvement in HAM-D scores than those in the placebo group, and by week 8, 52% of women taking creatine met criteria for remission, compared with 25.9% in the placebo group.17 These findings suggest that adding creatine monohydrate 5 g/day to SSRI treatment may enhance and speed up antidepressant response.

At the same time, this study should be interpreted with care. It focused specifically on women with major depressive disorder who were already being treated with escitalopram, so the findings do not mean creatine is a stand-alone treatment for depression. Larger studies are still needed to confirm the effect and better understand who might benefit most.

Overall, the women-specific research on creatine supplementation is promising. It suggests that creatine may support strength, performance, brain health, and possibly mood in women. But the evidence is still developing, and more large, well-designed studies are needed to clarify the best dose, the most effective form, and whether women respond differently than men.

Is creatine supplementation safe?

For most healthy people, creatine supplementation appears to be safe and well tolerated at 3 to 5 g/day.3 The most common side effects are mild stomach upset or cramping, which are usually temporary and more likely with higher doses.

Some creatine supplementation regimens involve a loading phase of about 20 g/day (see below), which may cause some water retention in the first several days. However, over longer periods, studies suggest that creatine does not greatly change total body water relative to muscle mass.3

Kidney safety has been studied closely. In people without existing kidney disease, there is no evidence that creatine at doses up to 5 g/day causes kidney damage. Reports of kidney problems have usually involved people with pre-existing kidney disease, taking other medications or supplements linked to kidney harm, or taking extremely high doses of creatine (e.g. 100x the recommended doses).3 Because creatine can raise blood creatinine, lab tests may look different even when the kidneys are healthy. People taking creatine supplements may wish to stop their supplement 1 to 2 weeks prior to having a creatinine blood test, or alternately, to use cystatin C as a measure of kidney function, which is not affected by creatine use.

Creatine doses up to 20 g/day appear safe in the short term, but there is less long-term safety data for higher doses.

Supplementation considerations

Almost all research on creatine supplementation has used creatine monohydrate, so it is considered the “gold standard”. For muscle and performance benefits, 3 to 5 g/day of creatine monohydrate appears to be enough for most people.

Two common approaches are used to build muscle creatine stores. The first is a loading protocol: about 20 g/day, usually split into four 5-gram doses, for 5 to 7 days, followed by 3 to 5 g/day. The second is a slow-saturation approach which involves going straight to the 3 to 5 g/day dose. Both methods work. Loading works faster, while slow saturation gets to similar muscle levels over a few weeks.18

For cognition and brain energy, higher doses such as 20g or more may be the most beneficial, especially in sleep-deprived settings. Current research suggests that taking a single dose of 20g immediately prior to a period of sleep deprivation, or 20 g/day for a week leading up to a period of sleep deprivation may reduce the negative cognitive and mood effects.

The time of day that creatine is taken does not seem to matter much, although some studies show that taking it with carbohydrates and/or protein may help to maintain glycogen stores in the muscle, potentially supporting recovery from exercise.3

Bottom line

Creatine monohydrate is one of the most well-studied supplements, and doses of 3 to 5 g/day may provide modest muscle and power benefits in people who resistance train regularly, with some potential cognitive benefits in older adults. Evidence continues to evolve regarding other applications of creatine supplementation, but it is possible that short-term high-dose supplementation (~20 g/day) could offset some of the detrimental effects of acute sleep deprivation.

Takeaways

• Creatine monohydrate is the best-studied form of creatine
• For muscle and performance benefits, creatine works best at 3 to 5 g/day and should be combined with resistance training
• Creatine monohydrate at doses of 3 to 5 g/day may cause some stomach upset and cramping, but extensive research indicates that it is safe for long-term use
• Higher creatine doses, around 20 grams per day, may help in short-term sleep deprivation or cognitive stress, but long-term data on effectiveness and safety of high-dose use is more limited
• People taking daily creatine supplements may have higher creatinine levels in the blood–some health care providers will recommend stopping creatine 1-2 weeks prior to testing creatinine, or testing cystatin C instead