By Eric Trexler, PhD
Eric Trexler is a Lecturing Fellow at Duke University where he teaches and conducts research related to exercise and nutrition. He is a former strength coach and pro natural bodybuilder who has published over 60 peer-reviewed papers about getting bigger, stronger, leaner, and healthier.
Should you take creatine?
Since around 1992, lifters have answered with a very confident “yes.” But we’ve learned a lot about creatine since then, and a surprising amount of that learning has occurred in the last couple years. So, let’s take a closer look at the most important takeaways from recent creatine research.
What Does Creatine Do?
Our cells need chemical energy to do their jobs. But not just any chemical energy – adenosine triphosphate (ATP) specifically. When you go on vacation to a country halfway around the world, you often need to exchange your native currency for whatever is used in that faraway land so you can pay for goods and services. In the human body, you need to convert your energy to the correct currency as well. Whether you traveled in with carbs, protein, fat, or ketones, you’ll need to transfer that over to ATP in order to make cells work.
There are numerous biochemical pathways to facilitate those transfers; some make the transfer very rapidly, and others take more time. High-intensity exercise like lifting weights and sprinting requires large amounts of ATP over very short periods of time. So, we have to use our most rapid source of ATP production – the phosphocreatine system – to produce ATP rapidly. During intense muscle activity, your muscles are churning through ATP, breaking it down into ADP. When this occurs, phosphocreatine (stored in the muscle) swoops in to donate a phosphate group which converts ADP back to ATP to fuel further muscle activity. Later on (when there’s less of an energy crunch), the resulting creatine will grab an extra phosphate group to “recharge” and become PCr again.
Our muscles contain stored phosphocreatine, but for most people, storage isn’t totally maxed out. By supplementing with creatine, we top off our phosphocreatine, maximizing our short-term energy production. The result is that you fail a couple reps later or complete that sprint a second or two faster.
Does Creatine Make Your Muscles Bigger?
Given how creatine works, it’s no surprise that creatine reliably improves strength and power outcomes. A tremendous volume of research indicates that creatine reliably improves strength (e.g., your one-rep max), power (e.g., repeated sprint speed), and muscular endurance (e.g., reps completed before failure).
That’s all great - but does it actually make your muscles bigger?
That may sound like a silly question, but it’s worth asking. We can’t always assume that a short-term strength or power improvement will translate to a long-term difference in muscle growth. In addition, creatine supplementation is known to increase total body mass and lean mass, but it’s also known to increase total body water. Water weight could theoretically be anywhere – increased plasma volume, a bloated gut, you name it. Simply looking at changes in body weight or lean mass won’t actually tell us if muscles got bigger. Which brings us back to our prior question: does creatine actually make your muscles bigger?
According to a 2023 meta-analysis, the answer is yes. Burke and colleagues analyzed the results of 10 studies that took direct measures of muscle size after at least 6 weeks of creatine supplementation (combined with resistance training). The results indicated that creatine increased muscle science, with a small (but non-zero) effect size of 0.11 standard deviations. In more relatable units, they found that muscle thickness increased by roughly 10-16 millimeters on average. With gains of such a small magnitude, we don’t exactly need to create a separate bodybuilding category for the mass monsters using creatine. Nonetheless, those modest gains are coming from a very affordable and very safe supplement, and they can add up over longer time scales.
Does Creatine Make Your Bones Stronger?
Given creatine’s remarkable track record for improving muscle-related outcomes, researchers intuitively wanted to know if creatine could also have positive effects on bones. It’s not a crazy idea. Bones use energy and adapt to the forces imposed by resistance training, so why wouldn’t a supplement that boosts energy production and allows for more forceful resistance training help out?
That’s very intuitive logic, but always remember: some true things don’t make sense, and some things that make sense aren’t true. According to a recent meta-analysis by Forbes and Candow, creatine comes up short when it comes to boosting bone density. To be clear, creatine does no harm to bones, it just isn’t bringing anything valuable to the table. Looking at bone density of the total skeleton, lumbar spine, and femoral neck (hip), all three showed virtually zero effect of creatine supplementation.
In summary, don’t believe all of the hype about creatine. It’s great for muscle, but it’s not meaningfully impacting bone.
Does Creatine Improve Brain Health or Function?
The human brain is the crown jewel of evolution, and it’s a calorie-burning machine. Think about it this way – fitness enthusiasts often talk about building more muscle to boost their resting energy expenditure. While muscle burns 13 calories per kilogram of tissue per day, brain tissue burns a staggering 240. In other words, if one pound of muscle burned as much energy as one pound of brain tissue, the average adult man’s resting metabolic rate would increase by about 7500 calories.
And your brain doesn’t just need energy – it specifically needs creatine. There’s an entire group of medical conditions known as cerebral creatine deficiency syndromes. These inherited conditions impact your brain’s ability to produce or transport creatine, and the ramifications are severe. Individuals with cerebral creatine deficiency often experience intellectual disability, developmental delay, seizures, and movement disorders. So, given the clear need for creatine in the brain, it seems like creatine supplementation is a surefire strategy for brain health and function… right?
As it turns out, the answer is a bit complicated.
One complicating factor is dosage. For muscle-building goals, the typical creatine dose required to maintain maximized muscle creatine storage is around 5 grams per day (or 0.07 grams per kg of body weight). For people who are just starting creatine (and in a hurry to saturated muscle storage), a common approach is to load ~20g per day (split among 4 doses) for a week to speed up the process, then drop back down to a maintenance dose. This will allow you to saturate muscle creatine levels in about a week (rather than the 3-4 week timeline you’d expect with a daily maintenance dose), but is a bit wasteful and may increase the likelihood of stomach discomfort. A less common middle ground approach, which I call “semi-loading,” involve taking ~10g per day (split among two doses) to fully saturated muscle creatine in about two weeks, then drop down to a maintenance dose of ~5g/day.
A typical maintenance dose (~5g/day) doesn’t seem large enough to meaningfully impact brain creatine levels. So, if you’re hoping to derive any brain benefits from creatine, you’ll need to be consuming more than the typical lifter. There’s nothing necessarily wrong with that, but consuming larger doses per day may increase the likelihood of mild stomach discomfort and definitely increases your annual creatine budget.
A second complicating factor is context. If you’re a young, healthy person eating a balanced diet, your brain works well. In such a scenario, we wouldn’t expect creatine to do much at all for brain health or cognitive function, which are already satisfactory. But when those “typical” circumstances are out the window, creatine may provide some benefits. As reviewed in a 2021 paper, emerging evidence suggests that creatine may be able to boost brain function in conditions that contribute to energy crunches in the brain. These include sleep deprivation, creatine synthesis enzyme deficiencies, mild traumatic brain injury, aging, Alzheimer's disease, mental fatigue, acute stress, depression, and aging.
But when it comes to creatine’s effects on these brain-related outcomes, there are three catches. First, this research is relatively new. A common phenomenon in research is for early studies on a new topic to seem particularly positive, followed by a wave of less exciting studies that extinguish the optimism. Whether or not that wave is coming is not yet known. Second, the positive studies to date indicate that you need a larger creatine dose to impact these brain-related outcomes. Conservatively you’d need around 10 grams per day (or 0.14 g/kg), but you may need as high as 20 grams per day (or 0.28 g/kg). In that case, we’re talking about opting in to a 100-300% markup above the “market price” for your typical creatine habit. A third, just to reiterate – the positive brain stuff has only been observed when the brain is actually in some sort of “deficit” – an artificially manipulated scenario that intentionally puts your brain into a scenario of suboptimal function. If you think you’re going to take some creatine and instantly notice massive cognitive benefits compared to your normal day-to-day function, you’ll be sorely disappointed.
Speaking of creatine and the brain, let’s get ahead of one myth in the making. A recent pilot study (that is, a very small and very preliminary study) found that creatine very slightly improved symptoms among people with Alzheimer’s disease. There has also been some interest in using creatine to manage symptoms of some other neurological conditions, such as Parkinson’s disease. This work is cool and valuable, but prone to misinterpretation. To be abundantly clear: no one has provided any evidence to suggest that creatine can prevent these conditions. They merely hope that creatine may partially attenuate some of the neurological and cognitive deficits after the disease has already progressed to the point of being symptomatic.
Finally, let’s address one area where big questions remain. Vegetarians (and especially vegans) often have larger positive responses to creatine supplementation in studies evaluating strength and power. This is because vegetarians tend to have lower muscular creatine levels at baseline (due to lack of creatine food sources in the diet). When a vegan and an omnivore take creatine for 8 weeks, the vegan will often experience a larger increase in storage because of their lower baseline level, which translates to better performance improvements. But does this translate to brain-related outcomes as well?
So far, it doesn’t seem to. Evidence to date suggests there is little to no difference when comparing brain creatine levels in vegetarians and omnivores. It’s very possible that brain creatine levels are simply too important (and therefore too tightly regulated) to allow for deviations based on dietary choices. One study is used frequently to suggest that vegetarians get a better memory boost from creatine than omnivores, and it’s cited time and time again. The only problem is that it didn’t find that at all.
The classic study by Benton and Donohoe reported that vegetarians had a “better” response to creatine than the omnivores. But if you read the fine print and dig into the results, you find a very curious result: creatine (or the passing of time) somehow made omnivories dumber. After creatine supplementation, omnivores’ scores on the cognitive task got worse, whereas vegetarians stayed roughly the same. This study does not indicate that vegetarians improved because they bolstered brain creatine stores that were low at baseline – it implies that creatine somehow impaired the cognitive function of omnivores, which makes no sense and is entirely at odds with the rest of the research in this area. The most likely outcome? Flukes happen, and this was probably a fluke.
So Should I Take Creatine Or Not?
If you’re a lifter who uses supplements, there is no safer bet than creatine. Its track record for strength and power performance is terrific, and new research confirms that it makes muscles bigger as well. For these outcomes, the classic 5 grams a day (or 0.07 g/kg) is plenty. When it comes to the optimal form of creatine, don’t overthink it. Creatine monohydrate is the gold standard, and alternative forms aren’t more effective because there really isn’t much room for improvement. Creatine monohydrate is safe, highly bioavailable, cost effective, and readily increases muscle creatine storage and improves performance – the quest to create new creatine formulations (for muscle-related outcomes) is a great example of looking for a solution without a problem.
If you’re looking to improve bone density or bone health, set your sights on higher priority items. You should focus on employing a solid resistance training program and adopting a well-balanced diet, with a particular focus on intakes of total energy, protein, calcium, and vitamin D.
If you’re trying to prevent neurological conditions like Alzheimer’s or Parkinson’s, I totally understand why, but creatine is unlikely to provide any benefit. For these types of conditions, the best case scenario is that creatine provides mild attenuation of symptoms, when used in conjunction with higher-priority treatment approaches, at high doses (~20 grams per day).
Finally, let’s say you’re dealing with some suboptimal cognitive conditions. Maybe you find that you’re chronically making important decisions when you’re sleep-deprived – emergency room clinicians don’t get to decide when medical emergencies occur, and firefighters on 48-hour shifts don’t get to choose when a fire starts. Or maybe you find that your cognitive function is slipping in frequently experienced scenarios of heightened stress or mental fatigue. Perhaps you’ve got a history of depression or anxiety and want to bolster your current approach to symptom management.
First, let me be extremely clear: creatine is not the best available intervention for any of these scenarios. The best way to address sleep deprivation is by sleeping more, and the best way to manage depression symptoms is by working with a qualified clinician to pursue more impactful treatment options (like therapy and medication). But if you’re interested in leveraging creatine to give your brain a boost in any or all of the scenarios described above, emerging evidence suggests that creatine may be worth a try. Given the preliminary nature of this science, consider it an experiment, not a sure-fire strategy.
In these types of scenarios, creatine probably needs to be dosed at somewhere between 10 - 20 grams per day, or roughly 0.14 - 0.28 grams per kilogram of body mass. So far, evidence suggests that you may need to err toward the higher end of that range to confidently increase creatine levels in the brain. For best results, break your creatine up into ~5 gram doses and separate them throughout the day. If you take very large doses all at once, your likelihood of stomach discomfort increases considerably. It’s worth noting that some preliminary research suggests that guanidinoacetic acid supplementation may increase brain creatine levels more efficiently than creatine alone, but we need more research in this area before firm conclusions can be made.
In summary, new research confirms that creatine is the cream of the crop when it comes to lifting-oriented supplements. As for its brain-related effects, the potential is there but currently unproven. Only time (and more research) will tell whether it delivers on the early promises and truly lives up to that potential.
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Eric Trexler, PhD
IG: @trexlerfitness
