B Complex Deficiency Signs That Look Like Early Cognitive Decline
Quick Read Some symptoms often blamed on aging, like brain fog and poor memory, may actually stem from B vitamin
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Creatine, best known as a gym supplement, may also support brain function by helping cells rapidly regenerate energy during demanding mental tasks. Your brain uses about 20% of your body’s energy at rest, and creatine acts as an energy buffer that helps refuel cells when they’re running low. Multiple studies show improvements in working memory, attention, and processing speed, particularly in people with lower baseline creatine levels like vegetarians, older adults, and those under cognitive stress.
A 2024 meta-analysis of 16 studies found consistent benefits for memory and mental speed with modest effect sizes. A 2025 review focused on adults over 55 found five out of six studies showed positive effects on memory and attention. However, the European Food Safety Authority concluded there is insufficient evidence to confirm a clear cause-and-effect relationship. A small pilot study in people with Alzheimer’s disease showed notable improvements in working memory and cognition, though results need verification in larger, controlled trials.
Creatine monohydrate is extremely safe at typical doses of 3 to 5 grams daily and is inexpensive. The evidence is most convincing for vegetarians, people over 55, and those experiencing periods of high cognitive demand like sleep deprivation. Younger, healthy meat eaters show weaker benefits. Most studies have been short term, so long-term effects remain unknown.
Verdict: Creatine shows promising, consistent benefits for brain function particularly in vulnerable populations, though the evidence is not yet definitive and may work best for those with naturally lower brain creatine stores.
What if the supplement sitting in the shaker bottles of gym-goers everywhere turned out to be one of the most interesting brain nutrients we’ve overlooked? What if the molecule your muscles crave to power through a heavy set is doing something quietly remarkable inside your skull, keeping your thinking sharp, your working memory firing, and your mental energy topped up? And what if the people who could benefit most from it have never once set foot in a weights room?
Creatine has spent decades being pigeonholed as a sports supplement, something for athletes chasing bigger lifts and faster recovery. But a growing body of research is asking a different question entirely: what is creatine doing for the brain? The answer, it turns out, is more interesting than most people realise. Vitacuity reviewed over 1.77 million research papers and selected the most relevant studies on this topic, and what emerged is a genuinely compelling, if still-evolving, story about energy, cognition and the remarkable demands your brain places on your biology every single day.
To understand why creatine might matter for your mind, you first need to understand what your brain actually runs on, and how demanding it is.
Your brain is an extraordinarily energy-hungry organ. It accounts for roughly 2% of your body weight but consumes around 20% of your body’s energy at rest. That energy comes in the form of adenosine triphosphate, ATP, the cellular currency that powers virtually everything your body does. The problem is that your cells can’t store large amounts of ATP. They need a rapid way to regenerate it when demand spikes, like when you’re concentrating hard, processing complex information, or holding several things in mind at once.
This is where creatine comes in. Creatine acts as what researchers describe as a “temporal and spatial energy buffer” [6]. When ATP gets used up and loses one of its phosphate groups to become ADP (adenosine diphosphate), creatine, in its phosphorylated form, phosphocreatine, can rapidly donate a phosphate group back, regenerating ATP on the spot. It’s essentially a rapid-recharge system for cellular energy.
The brain has its own creatine stores, and those stores matter. When cognitive demand increases, during complex problem-solving, sustained attention, or working memory tasks, your brain’s energy requirements spike. If creatine helps buffer that spike more efficiently, it may help maintain performance under pressure. More recently, researchers have also proposed that creatine may reduce oxidative stress, decrease inflammation, and even influence the muscle-brain axis, a communication pathway between skeletal muscle and the brain involving compounds called myokines, including brain-derived neurotrophic factor (BDNF), which plays a role in neuroplasticity and cognitive health [5]. These are emerging ideas, but they help explain why creatine’s effects on the brain may be more multifaceted than simply “topping up the ATP tank.”
Evidence grade: Promising, multiple small RCTs, consistent direction but modest sample sizes
The most cited human study on creatine and cognition is still one of the most striking. Published in *Proceedings of the Royal Society B* in 2003, researchers at the University of Sydney ran a double-blind, placebo-controlled crossover trial in 45 young adult vegetarians [6]. Participants supplemented with 5g of creatine monohydrate per day for six weeks, then crossed over to placebo.
The results were notable. Creatine supplementation produced a statistically significant improvement in both working memory, measured by backward digit span, a task where you repeat a sequence of numbers in reverse order, and intelligence, measured by Raven’s Advanced Progressive Matrices, a test of abstract reasoning and pattern recognition. The effect size was meaningful and the p-value was striking (p < 0.0001) [6].
Why vegetarians? The reasoning matters here. Creatine is found almost exclusively in meat and fish. Vegetarians and vegans tend to have lower baseline creatine stores in both muscle and brain. That means supplementation has more “room to work” in people who aren’t regularly topping up their stores through diet. This is a key detail that will become important later.
A 2023 randomised controlled trial, the largest of its kind on this topic, extended this work [15]. Researchers ran a preregistered, double-blind, placebo-controlled crossover trial in 123 participants, again using 5g daily for six weeks, testing on the same backward digit span and Raven’s matrices. About half the participants were vegetarians and half omnivores.
The result? Bayesian analysis supported a small beneficial effect of creatine, though the working memory result bordered statistical significance (p = 0.064). Crucially, the study found that vegetarians showed a stronger response than omnivores, which aligns with the dietary baseline theory [15]. The authors’ conclusion was measured but clear: creatine “might have a small beneficial effect,” and given its safety and availability, that’s well worth taking seriously at scale.
Evidence grade: Promising, 16 RCTs, consistent positive signal across memory and processing speed
In 2024, researchers published a systematic review and meta-analysis in *Frontiers in Nutrition*, pooling data from 16 randomised controlled trials involving 492 participants aged 20.8 to 76.4 years [9]. This is the most comprehensive quantitative synthesis of the evidence to date.
The findings were positive for several cognitive domains. Creatine supplementation showed significant effects on:
– Memory (standardised mean difference = 0.31, 95% CI: 0.18–0.44) – Attention processing time – Information processing speed
Effect sizes in this territory are considered small-to-moderate, meaningful at a population level, and potentially important for individuals whose daily cognitive performance matters to them professionally or personally. Executive function showed a trend in the positive direction but did not reach significance across the pooled sample [9].
The authors were appropriately cautious: they called for larger, more robust trials and noted that different populations and intervention durations likely produce different outcomes. But the overall weight of evidence pointed in a consistent direction, creatine appears to support memory and mental speed in adults.
Evidence grade: Promising, six studies, 1,542 participants, predominantly positive findings but methodological quality is mixed
A 2025 systematic review published in *Nutrition Reviews* specifically examined the evidence for creatine and cognition in older adults (aged 55 and over) [2, 12]. Researchers searched eight electronic databases, ultimately including six studies with a total of 1,542 participants, 55.7% of them female.
Five of the six studies (83.3%) reported a positive relationship between creatine and cognition, particularly in the domains of memory and attention [2, 12]. Two of the six studies were double-blind interventions directly supplementing participants with creatine monohydrate; the other four were cross-sectional studies estimating creatine intake through dietary recall.
Here the authors were honest about the limitations: only one study achieved a “good” methodological quality rating, two were rated “fair,” and three were rated “poor.” This is important context, promising doesn’t mean proven. But the direction is consistent and the populations studied (healthy, community-dwelling older adults) are precisely the people who might benefit most from protecting and maintaining cognitive function over time.
Evidence grade: Promising, small sample, but an interesting and specific finding
One of the more intriguing angles on creatine and cognition is what happens when the brain is under stress, specifically, when it’s running short on sleep. A 2007 study published in *Physiology & Behavior* divided participants into a creatine group and a placebo group, both taking 5g four times a day for seven days before the trial [11]. Participants then underwent 18, 24 and 36 hours of sleep deprivation combined with moderate intermittent exercise, with cognitive testing at each interval.
The creatine group performed significantly better on a central executive task, complex cognitive processing, but only at the 36-hour mark (p < 0.05) [11]. The creatine group also showed a significant linear improvement across the trial on this task, while the placebo group showed no such pattern. No significant differences were found for simpler tasks like short-term memory or reaction time.
The interpretation? Creatine appears most useful for the brain when demand is high and reserves are depleted. Sleep deprivation is a form of metabolic stress, it compromises brain energy metabolism. Creatine’s role as an energy buffer may help the brain maintain performance on complex tasks when it’s running on empty. This resonates with the broader hypothesis that creatine is most impactful when baseline stores are low or when cognitive demand is acute.
Evidence grade: Early stage, single-arm, open-label pilot, n=20, no control group. Results are hypothesis-generating, not conclusive
This one needs a significant caveat upfront: it’s a small, uncontrolled pilot study. But it’s striking enough to report honestly, alongside those limitations.
A 2025 pilot trial enrolled 20 participants with dementia due to probable Alzheimer’s disease (mean age 73.1 years) in an eight-week open-label intervention using 20g per day of creatine monohydrate [3, 13]. There was no placebo group, which is a meaningful limitation.
The results, if they replicate under controlled conditions, would be remarkable:
– Whole brain total creatine increased by 11.0% (p < 0.001) - Lymphocyte ATP production increased 2.9-fold (p = 0.004) - Global fluid cognition improved by 4.4 points (p = 0.004) - Working memory improved by 8 points (p < 0.001) - Executive function improved by 5 points (p = 0.05)
Serum creatine levels increased 8.4-fold at four weeks and 9.0-fold at eight weeks, confirming the supplement was absorbed and reaching the brain [3, 13]. In female participants specifically, mitochondrial respiration showed significant increases across multiple measures.
The researchers were clear that these are preliminary findings requiring replication in controlled trials. But the direction is consistent with the broader hypothesis: that creatine may support brain bioenergetics in a meaningful way, particularly when the brain’s own creatine system is impaired, as appears to be the case in Alzheimer’s disease. The dose used here (20g/day) is higher than typical supplementation protocols and was used specifically in a clinical context.
Evidence grade: Early stage, theoretical framework with mechanistic support, human trial data needed
A 2025 paper in *Frontiers in Nutrition* proposed an intriguing additional mechanism for creatine’s cognitive effects, one that goes beyond simple ATP buffering [5]. The hypothesis centres on the muscle-brain axis: the idea that skeletal muscle communicates with the brain through signalling molecules called myokines.
When muscles are working well and well-nourished (including with creatine), they secrete myokines, including BDNF, brain-derived neurotrophic factor. BDNF is one of the brain’s most important growth factors, linked to neuroplasticity, memory formation, and protection against cognitive decline [5]. The theory suggests that creatine’s well-established benefits to muscle mass and energy metabolism may have downstream benefits for brain health through this muscle-brain communication pathway.
This is speculative at present, the authors themselves call for further research to verify the hypothesis. But it raises a genuinely interesting possibility: that creatine may support cognition not just directly (through brain energy metabolism) but indirectly, through its effects on muscle health and the signalling it triggers. For older adults in particular, where both muscle mass and cognitive function tend to decline in parallel, this dual pathway is worth watching.
The honest answer is: quite a lot. And the most important gaps are worth naming clearly.
The EFSA verdict: In 2024, the European Food Safety Authority reviewed the available evidence for a health claim linking creatine to improved cognitive function [8]. Their conclusion was that a cause-and-effect relationship has not been established. They noted that acute effects on working memory were observed at high doses (20g/day for 5–7 days), but were not consistently seen at lower doses, and that continuous supplementation at 5g/day did not produce the same effects in healthy individuals. The EFSA panel found the mechanistic evidence weak and concluded that the existing intervention studies, particularly in diseased populations, did not support the claim [8].
This is a genuine and important challenge to the narrative. EFSA’s bar for health claims is high and deliberately conservative, but that doesn’t mean the finding should be dismissed. It means the evidence, while promising in direction, is not yet robust enough for certainty.
The dose question: Studies have used doses ranging from 2.2g to 20g per day, with durations from five days to six weeks. These are dramatically different protocols, making direct comparison difficult. The 2018 systematic review found that effects on short-term memory and intelligence were observed, but results for other cognitive domains were conflicting, possibly because different doses, populations and tasks were used [7].
Who benefits most? The evidence is most consistent for people with lower baseline creatine levels, vegetarians, vegans, older adults eating less meat, and people under cognitive stress. The evidence for younger, healthy omnivores is considerably weaker. The 2023 large RCT found only a borderline effect in this population [15].
The animal data: The 2025 rat studies on spatial working memory [1, 10] are interesting but remind us that animal findings don’t always translate to humans. They shouldn’t be weighted heavily in isolation.
Long-term data: Almost all intervention studies are six weeks or shorter. We don’t know what sustained creatine supplementation does for cognitive trajectories over months or years.
The Alzheimer’s findings [3, 13], while intriguing, come from a 20-person, open-label pilot with no control group. Placebo effects in cognition can be substantial. These results are hypothesis-generating, not conclusive.
So, what would a sensible, well-informed person actually do with all of this?
First, let’s be clear about what the evidence does and doesn’t support. Creatine is not a proven cognitive enhancer for all people in all circumstances. EFSA declined to approve a health claim. The research is promising but still building. That’s the honest picture.
And yet, here’s the equally honest practical perspective. Creatine monohydrate is one of the most extensively safety-tested supplements in existence. At doses of 3–5g per day, it has an extraordinary safety record accumulated over decades of sports nutrition research. It is inexpensive, widely available, and has well-established benefits for muscle and bone health, benefits that become increasingly important from your 40s onwards as natural muscle mass begins to decline.
Against that backdrop, the cognitive evidence, while not definitive, points consistently in the right direction, particularly for:
– People who eat little or no meat (vegetarians, vegans, flexitarians), your baseline brain creatine stores are likely lower, and the evidence suggests you respond more strongly to supplementation – People over 55, the 2025 systematic review found positive effects on memory and attention in this group, and the muscle health benefits alone make supplementation reasonable [2, 12] – People experiencing periods of cognitive stress, poor sleep, demanding workloads, high mental load, the sleep deprivation study suggests creatine may help buffer performance under these conditions [11]
What to actually do:
– 3–5g of creatine monohydrate per day is the evidence-backed dose for long-term daily use. This is the dose used in most cognitive studies and has an excellent safety profile. – Take it consistently, effects appear to build with sustained use as brain stores gradually increase. – Creatine monohydrate is the form used in virtually all research, don’t pay extra for fancier branded forms without strong evidence they’re superior. – You don’t need to “load” at high doses (20g/day) for cognitive purposes, that was used in clinical studies and the EFSA review noted that effects at lower doses were less consistent, but the long-term daily approach is more practical and sustainable. – If you eat meat regularly and are under 40 with no particular cognitive demands or sleep issues, the evidence for you specifically is thinner, though the muscle and bone benefits remain.
The bottom line: creatine is safe, cheap, well-understood and increasingly interesting for brain health. The research isn’t finished, but it’s pointing somewhere worth paying attention to. And for a supplement that costs pennies per day, the risk-benefit calculation is straightforward.
[1] Effect of Creatine Monohydrate on Spatial Working Memory, Body Weight, and Food Intake in Male and Female Rats (2025). DOI: 10.3390/nu17132218 | https://pubmed.ncbi.nlm.nih.gov/40647322/ | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12251355/
[2] Creatine and Cognition in Aging: A Systematic Review of Evidence in Older Adults (2025). DOI: 10.1093/nutrit/nuaf135 | https://pubmed.ncbi.nlm.nih.gov/40971619/
[3] Creatine Monohydrate Supplementation in Alzheimer’s Disease, Pilot Trial (2025). DOI: 10.1002/alz70858_100477 | https://pubmed.ncbi.nlm.nih.gov/41445099/ | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12739067/
[4] Effects of Creatine Monohydrate Loading on Sleep Metrics, Physical Performance, Cognitive Function, and Recovery in Physically Active Men: A Randomized, Double-Blind, Placebo-Controlled, Crossover Trial (2025). DOI: 10.3390/nu17243831 | https://pubmed.ncbi.nlm.nih.gov/41470776/ | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12736258/
[5] Creatine supplementation and muscle-brain axis: a new possible mechanism? (2025). DOI: 10.3389/fnut.2025.1579204 | https://pubmed.ncbi.nlm.nih.gov/40771202/ | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12325066/
[6] Oral creatine monohydrate supplementation improves brain performance: a double-blind, placebo-controlled, cross-over trial (2003). DOI: 10.1098/rspb.2003.2492 | https://pubmed.ncbi.nlm.nih.gov/14561278/ | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1691485/
[7] Effects of creatine supplementation on cognitive function of healthy individuals: A systematic review of randomized controlled trials (2018). DOI: 10.1016/j.exger.2018.04.013 | https://pubmed.ncbi.nlm.nih.gov/29704637/
[8] Creatine and improvement in cognitive function: Evaluation of a health claim pursuant to article 13(5) of regulation (EC) No 1924/2006 (2024). DOI: 10.2903/j.efsa.2024.9100 | https://pubmed.ncbi.nlm.nih.gov/39564533/ | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11574456/
[9] The effects of creatine supplementation on cognitive function in adults: a systematic review and meta-analysis (2024). DOI: 10.3389/fnut.2024.1424972 | https://pubmed.ncbi.nlm.nih.gov/39070254/ | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11275561/
[10] Effect of Creatine Monohydrate on Spatial Working Memory, Body Weight, and Food Intake in Male and Female Rats (2025). DOI: 10.3390/nu17132218 | https://pubmed.ncbi.nlm.nih.gov/40647322/ | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12251355/
[11] Creatine supplementation, sleep deprivation, cortisol, melatonin and behavior (2007). https://pubmed.ncbi.nlm.nih.gov/17046034/
[12] Creatine and Cognition in Aging: A Systematic Review of Evidence in Older Adults (2025). DOI: 10.1093/nutrit/nuaf135 | https://pubmed.ncbi.nlm.nih.gov/40971619/
[13] Creatine Monohydrate Supplementation in Alzheimer’s Disease, Pilot Trial (2025). DOI: 10.1002/alz70858_100477 | https://pubmed.ncbi.nlm.nih.gov/41445099/ | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12739067/
[14] Effects of Creatine Monohydrate Loading on Sleep Metrics, Physical Performance, Cognitive Function, and Recovery in Physically Active Men: A Randomized, Double-Blind, Placebo-Controlled, Crossover Trial (2025). DOI: 10.3390/nu17243831 | https://pubmed.ncbi.nlm.nih.gov/41470776/ | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12736258/
[15] The effects of creatine supplementation on cognitive performance, a randomised controlled study (2023). DOI: 10.1186/s12916-023-03146-5 | https://pubmed.ncbi.nlm.nih.gov/37968687/ | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10647179/
This article is for informational purposes only and does not constitute medical advice. Food supplements should not be used as a substitute for a varied and balanced diet and healthy lifestyle. If you are pregnant, breastfeeding, taking medication or have a medical condition, consult your doctor before taking any supplement. These statements have not been evaluated by the Food and Drug Administration (FDA) or the Medicines and Healthcare products Regulatory Agency (MHRA). This product is not intended to diagnose, treat, cure, or prevent any disease.
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