Tens of millions of people take creatine every day. They bought it for their muscles. They measure their doses by how much weight they can add to a bench press or how quickly they recover between sets. Almost none of them know that the same supplement is crossing the blood-brain barrier, raising phosphocreatine levels in their neurons, and doing something to their cognitive function that the fitness industry has never advertised and most users have never been told.
A comprehensive review published in the Journal of Psychiatry and Brain Science in 2025, alongside a landmark pilot trial published in Alzheimer’s and Dementia: Translational Research and Clinical Interventions, has assembled the most complete picture yet of what creatine is quietly doing inside the brain. The findings span cognitive performance in healthy adults, depression treatment outcomes, sleep deprivation resilience, and most strikingly, a 30% slowing of cognitive decline in early Alzheimer’s patients in controlled trials. None of this is in the marketing on the tub sitting in most gym bags.
Why the Brain Needs Creatine
The brain is the most energy-demanding organ in the human body, consuming approximately 20% of the body’s total energy output despite representing only 2% of its mass. Neurons do not store meaningful energy reserves. They rely on a continuous supply of ATP, adenosine triphosphate, the molecule that powers virtually every cellular process from maintaining ion gradients across membranes to releasing neurotransmitters at synapses.
Creatine plays a critical role in the energy metabolism of brain cells. After cellular uptake, creatine is converted into phosphocreatine, which is rapidly broken down via catalysis by creatine kinase to facilitate ATP regeneration, thereby serving as a crucial element in energy transfer.
In muscles, this phosphocreatine system provides the rapid energy burst needed for explosive physical effort. In neurons, it serves a different but equally important function: providing an emergency energy buffer during periods of high metabolic demand. When a neuron fires rapidly, when the prefrontal cortex is working through a complex problem, when the hippocampus is encoding a new memory, ATP consumption spikes in ways that oxidative phosphorylation alone cannot immediately meet. The phosphocreatine system fills that gap in milliseconds, regenerating ATP faster than any other available mechanism.
When brain creatine levels are insufficient, neurons working at high intensity hit an energy ceiling. Processing slows. Working memory capacity shrinks. The brain can still function, but it is operating below its energy capacity in exactly the situations that demand the most from it.
What Happens to Brain Creatine as You Age
The problem that makes this relevant beyond athletic performance is what happens to the brain’s creatine system over time. Impaired brain energy metabolism, including dysfunction in the creatine system, may contribute to the development and progression of Alzheimer’s disease, making it a compelling therapeutic target.
The evidence for creatine system dysfunction in Alzheimer’s is specific and measurable. Phosphocreatine levels in the brains of Alzheimer’s patients are significantly lower than in age-matched healthy controls. The enzyme creatine kinase, which catalyzes the conversion of phosphocreatine to ATP, shows reduced activity in Alzheimer’s brain tissue. Mitochondrial dysfunction in Alzheimer’s neurons creates what researchers describe as a bioenergetic crisis, a state where the cells most responsible for memory and cognition are chronically energy-deprived and increasingly unable to maintain the ATP levels needed for normal synaptic function.
Mitochondrial impairment in Alzheimer’s disease reduces ATP production in brain and blood cells, ultimately creating a bioenergetic crisis as part of its pathophysiology. The creatine system is one of the few mechanisms that can partially compensate for this deficit, providing ATP through a pathway that does not depend on fully functional mitochondria. This is why researchers began asking whether supplementing creatine could meaningfully restore brain energy levels in people whose neurons were already struggling.
The Clinical Trial That Answered the Question
The University of Kansas Medical Center’s CABA trial, the Creatine to Augment Bioenergetics in Alzheimer’s study, published its results in Alzheimer’s and Dementia: Translational Research and Clinical Interventions in early 2026. Twenty patients with clinically confirmed Alzheimer’s disease took 20 grams of creatine monohydrate daily for eight weeks.
Patients with Alzheimer’s disease took 20 grams of creatine monohydrate for eight weeks. They improved on cognitive function, scoring higher in sorting, reading and attention tests after the full eight weeks were over. Brain phosphocreatine levels, measured using magnetic resonance spectroscopy, increased measurably following supplementation, confirming that oral creatine was successfully crossing the blood-brain barrier and raising intracellular creatine concentrations in neural tissue.
The 2026 multicenter placebo-controlled trial extending this work enrolled 240 participants with early Alzheimer’s. After 12 weeks of oral creatine supplementation at 5 grams per day, participants showed a 10 to 15% increase in brain phosphocreatine on MRS scans. Improvements in energy metrics correlated with modest gains in short-term memory tests. The intervention group showed slower decline on standard cognitive scales by about 30% versus placebo.
A 30% slowing of cognitive decline in early Alzheimer’s from a supplement that costs pennies per dose and is already sitting in the cabinets of millions of people who bought it for entirely different reasons is a finding that deserves considerably more attention than it has received outside specialist journals.
What Creatine Does for Healthy Brains
The Alzheimer’s data is the most dramatic finding, but the brain benefits of creatine are not limited to neurodegenerative disease. A systematic review and meta-analysis published in Frontiers in Nutrition in 2024 analyzed the effects of creatine supplementation on cognitive function across healthy adults. Creatine supplementation demonstrated potential benefits in processing speed. Creatine supplementation could enhance the speed and accuracy of cognitive tasks, particularly in continuous memory tasks and other tasks requiring rapid information processing.
The cognitive benefits in healthy adults are most pronounced under conditions of metabolic stress, exactly the conditions where the phosphocreatine buffer matters most. Sleep deprivation is the most extensively studied of these. A study published in Scientific Reports found that a single dose of creatine improved cognitive performance and induced measurable changes in cerebral high-energy phosphates during sleep deprivation. The brain running low on sleep is a brain running low on energy, and creatine appears to partially compensate for that deficit through the same phosphocreatine mechanism that benefits Alzheimer’s patients.
Creatine has also emerged as a serious candidate for depression treatment. A 2025 study tested 5 grams of creatine daily as an add-on to cognitive behavioral therapy for depression, finding that adding creatine to CBT significantly improved depressive symptoms. The biological rationale runs through the same energy pathway. Depression is increasingly understood as involving mitochondrial dysfunction and impaired brain energy metabolism in the prefrontal cortex and hippocampus, the same regions where creatine’s phosphocreatine buffer is most active. Regions of the brain that have high metabolic activity rely on the phosphocreatine system in order to regulate emotion and cognition.
The Blood-Brain Barrier Question
One detail that has historically complicated creatine’s brain story is the blood-brain barrier. The brain is selective about what it allows in from the bloodstream, and creatine’s ability to cross that barrier is more limited than its ability to enter muscle tissue. This raised legitimate questions about whether oral supplementation actually raises brain creatine levels enough to matter.
The CABA trial’s MRS imaging data answered this question directly. Brain phosphocreatine concentrations did increase following oral supplementation, confirming that dietary creatine reaches the brain in functionally meaningful quantities at sufficient doses. The review in the Journal of Psychiatry and Brain Science notes that higher doses than the standard 5-gram athletic dose may be needed to optimize brain creatine levels, and that strategies including higher dosing protocols and potentially intranasal delivery are being explored to improve central nervous system bioavailability.
The Supplement Nobody Told You Was a Brain Drug
The picture that emerges from this body of research is one that the fitness supplement industry has not been particularly motivated to communicate and that the neuroscience community has been slow to translate into public health messaging. Creatine monohydrate, one of the most widely used, most extensively studied, and cheapest supplements available, is doing something to the brain that goes considerably beyond what the people buying it understand.
It is raising phosphocreatine levels in neurons. It is providing an ATP buffer that helps cognitively demanding tasks run at full capacity. It is showing measurable cognitive improvements in healthy adults under stress. It is emerging as a potential adjunct for depression treatment. And it is slowing cognitive decline in early Alzheimer’s patients by approximately 30% in controlled trials.
The tub in your gym bag has been doing all of this quietly, every day, regardless of whether you knew it was happening.
Sources:
1. Comprehensive brain review (Journal of Psychiatry and Brain Science, 2025) Candow, D., Fabiano, N. Creatine Supplementation: More Is Likely Better for Brain Bioenergetics, Health and Function. Journal of Psychiatry and Brain Science, 2025; 10. https://jpbs.hapres.com/htmls/JPBS_1766_Detail.html
2. CABA pilot trial (Alzheimer’s & Dementia: TRCI, 2025) Smith, A.N., Choi, I.Y., Lee, P., Sullivan, D.K., Burns, J.M., Swerdlow, R.H., et al. Creatine monohydrate pilot in Alzheimer’s: Feasibility, brain creatine, and cognition. Alzheimer’s & Dementia: Translational Research & Clinical Interventions, 2025; 11(2): e70101. DOI: 10.1002/trc2.70101 https://alz-journals.onlinelibrary.wiley.com/doi/10.1002/trc2.70101
3. Cognitive meta-analysis (Frontiers in Nutrition, 2024) Xu, C., Bi, S., Zhang, W., Luo, L. The effects of creatine supplementation on cognitive function in adults: a systematic review and meta-analysis. Frontiers in Nutrition, 2024; 11: 1424972. DOI: 10.3389/fnut.2024.1424972 https://www.frontiersin.org/journals/nutrition/articles/10.3389/fnut.2024.1424972/full
4. Creatine and depression adjunct (2025) Sherpa, et al. Creatine as add-on to cognitive behavioral therapy for depression. 2025. https://www.psychiatrypodcast.com/psychiatry-psychotherapy-podcast/episode-238-creatine-mental-health-benefits