Literature Review · Nutrition & Supplements · Cognitive Health
Creatine and Cognition in APOE ε4 Carriers: What the Evidence Actually Shows
By Brian Paquette, DO, MPH
Creatine is biologically plausible and well studied for physical performance, but it is not an evidence-based treatment for cognitive impairment in APOE ε4 carriers. No randomized trial has tested it in mild cognitive impairment, and the Alzheimer disease evidence is a single 20-person, eight-week, uncontrolled pilot.
The clinical problem
Creatine has moved from the gym to the longevity conversation, and APOE ε4 carriers increasingly ask whether it can protect memory. The question deserves a population-specific answer: what is known in cognitively normal older adults does not transfer automatically to people with mild cognitive impairment (MCI) or Alzheimer disease, and nothing yet has been shown specifically in carriers.
APOE4 Insights evidence rating
| Population | Rating | Practical conclusion |
| APOE ε4 carriers with MCI | 1/5 — Very low | No dedicated clinical trials identified. |
| APOE ε4 carriers with mild-to-moderate Alzheimer disease | 1/5 — Very low | One uncontrolled pilot; no genotype-specific efficacy analysis. |
| Cognitively normal older adults | 2/5 — Low | A possible small memory benefit remains uncertain. |
Rating framework: 1/5 = very low or insufficient; 2/5 = low; 3/5 = moderate; 4/5 = moderate to high; 5/5 = high. The rating reflects confidence in a cognitive benefit for the stated population — not creatine’s general safety record or its usefulness for muscle performance.
What the evidence shows
Cognitively normal older adults
The best signal comes from generally healthy older adults, but confidence remains low. A systematic review of six studies in adults aged 55 and older found that five reported a positive association or effect, chiefly in memory and attention. Only one study was rated methodologically good; two were fair and three were poor. Four of the six were cross-sectional and cannot establish that creatine caused better cognition.[2]
A meta-analysis of randomized trials in healthy people reported a small overall memory benefit (standardized mean difference 0.29). The effect was larger in participants aged 66–76, but that subgroup rested on only two small studies, one of them positive.[3] A separate 2024 meta-analysis reported possible benefits for memory and processing speed, but no clear improvement in overall cognition, attention, or executive function.[4]
Negative evidence carries equal weight. In a 24-week randomized trial of 56 older women, creatine — 20 grams daily for five days, then 5 grams daily — did not improve cognitive or emotional measures.[6] An observational NHANES analysis associated higher dietary creatine intake with better performance on one processing-speed test in adults aged 60 and older, but residual confounding and reverse causation remain possible.[7]
In 2024, the European Food Safety Authority reviewed a proposed cognitive health claim and concluded that a cause-and-effect relationship had not been established, citing non-independent outcomes and participant double-counting in one synthesis.[5]
Mild cognitive impairment
Systematic and scoping reviews identified no dedicated randomized trial of creatine as an isolated intervention in MCI.[2,12] There is therefore no clinical basis for claiming that creatine slows progression, improves daily function, or meaningfully improves cognition in MCI — including in APOE ε4 carriers.
Mild-to-moderate Alzheimer disease
Human evidence consists of a single eight-week pilot in 20 people with probable Alzheimer disease who took creatine monohydrate 20 grams daily. Brain total creatine rose by about 11 percent, and several NIH Toolbox measures improved from baseline.[1] But the study had no placebo group, was open label and short, and tested multiple cognitive outcomes. Practice effects, expectancy, regression to the mean, and chance cannot be excluded.
Thirteen of the 20 participants carried at least one APOE ε4 allele. That confirms carriers were represented; it does not demonstrate benefit in carriers. The study was neither designed nor powered for a genotype-by-treatment analysis.[1]
The headline: the only Alzheimer disease trial is uncontrolled, and there is no MCI trial at all. No study has tested whether creatine helps cognition specifically in APOE ε4 carriers.
Why APOE ε4 is still scientifically relevant
Creatine buffers rapid changes in cellular energy demand through the creatine–phosphocreatine system. Several findings make this pathway worth studying in carriers without showing that supplementation works:
- Reduced brain creatine kinase. Astrocytic brain-type creatine kinase is reduced in Alzheimer tissue, in association with plaque and tau burden.[8]
- Genotype- and sex-related energy differences. A phosphorus magnetic resonance spectroscopy study of 209 cognitively normal, middle-aged adults at increased Alzheimer risk found sex- and APOE ε4-related differences in brain high-energy phosphate measures.[9]
- Lower measured brain creatine. A meta-analysis of in vivo spectroscopy studies found lower brain creatine in MCI and Alzheimer disease. This supports altered bioenergetics; it does not show a dietary deficiency or that oral supplementation would correct it.[10]
These observations justify research into creatine and brain energy metabolism. They should not be converted into a treatment recommendation.
Sex may modify response
In the 3xTg transgenic Alzheimer mouse model, chronic creatine supplementation improved spatial cognition in females, while males showed a trend toward worse performance.[11] Because APOE ε4-related risk and brain energy metabolism also differ by sex, this signal warrants attention in future trials.
It does not establish that creatine harms cognition in men. In the 20-person human pilot, brain-creatine and cognitive responses were broadly similar by sex, but the sample was far too small to rule out clinically important differences.[1] Future trials should be randomized, placebo-controlled, and stratified by both sex and APOE genotype.
Dose and safety
The Alzheimer pilot used 20 grams per day, divided into four doses, for eight weeks.[1] That is a research loading regimen, not a validated cognitive dose. The common maintenance dose of 3–5 grams per day has not been shown to improve cognition in MCI, Alzheimer disease, or APOE ε4 carriers.
Creatine monohydrate has a generally favorable safety record in healthy adults; water-related weight gain and gastrointestinal symptoms are the most common concerns.[13] In the Alzheimer pilot, all 13 reported adverse events were mild, including cramping or muscle pain, diarrhea, constipation, nausea, flushing, and sleep disturbance.[1]
Creatine can raise serum creatinine, because creatinine is a breakdown product of creatine. This can make creatinine-based kidney-function estimates look worse without any true fall in filtration.[13] People with kidney disease, significant comorbidity, or complex medication regimens should discuss supplementation with their clinician and may need a different approach to renal monitoring.
Evidence strength summary
| Claim | Verdict | Basis |
| Creatine improves memory in healthy adults | Weak — small, uncertain | Meta-analyses of small RCTs; EFSA did not accept the claim [3–5] |
| Creatine helps cognition in MCI | No evidence | No dedicated RCT identified [2,12] |
| Creatine helps cognition in Alzheimer disease | Very weak | One uncontrolled 20-person pilot [1] |
| Creatine benefits APOE ε4 carriers specifically | No evidence | Never tested by genotype [1] |
| Creatine is safe for most healthy adults | Supported | Position stand and trial safety data [1,13] |
Clinical bottom line
1. Not a cognitive treatment. Creatine should not currently be represented as a treatment for MCI or Alzheimer disease, in carriers or anyone else.
2. Other indications can still justify it. Creatine may be reasonable for an established indication, such as supporting resistance training, after considering individual health factors.
3. Do not self-prescribe the pilot dose. A 20-gram-per-day cognitive regimen should not be adopted on the strength of one uncontrolled eight-week study.
4. Watch the creatinine. Tell clinicians about supplementation so a rise in serum creatinine is not misread as kidney decline.
Limitations
This is a narrative review. The human evidence consists of small, short trials, cross-sectional observations, and a single uncontrolled pilot; the sex-difference signal comes from one mouse model. No included study was stratified by APOE genotype. The evidence rating is an editorial judgment applied consistently across APOE4 Insights reviews, not a formal GRADE assessment. The EFSA opinion is a regulatory scientific evaluation, and the International Society of Sports Nutrition position stand comes from a sports-nutrition society whose members include researchers with supplement-industry ties. The appropriate next step is an adequately powered randomized trial with prespecified cognitive and functional outcomes, biomarker measures, and sex-by-APOE analyses.
References
1. Smith AN, et al. Creatine monohydrate pilot in Alzheimer’s: feasibility, brain creatine, and cognition. Alzheimers Dement (N Y). 2025;11:e70101. doi:10.1002/trc2.70101
2. Marshall S, et al. Creatine and cognition in aging: a systematic review of evidence in older adults. Nutr Rev. 2026. PubMed
3. Prokopidis K, Giannos P, Triantafyllidis KK, et al. Effects of creatine supplementation on memory in healthy individuals: a systematic review and meta-analysis of randomized controlled trials. Nutr Rev. 2023;81:416–427. PubMed
4. Xu C, et al. The effects of creatine supplementation on cognitive function in adults: a systematic review and meta-analysis. Front Nutr. 2024;11:1424972. doi:10.3389/fnut.2024.1424972
5. EFSA Panel on Nutrition, Novel Foods and Food Allergens. Creatine and improvement in cognitive function: evaluation of a health claim. EFSA J. 2024;22:e9100. doi:10.2903/j.efsa.2024.9100
6. Alves CRR, et al. Creatine supplementation associated or not with strength training upon emotional and cognitive measures in older women: a randomized double-blind study. PLoS One. 2013;8:e76301. doi:10.1371/journal.pone.0076301
7. Ostojic SM, et al. Dietary creatine and cognitive function in U.S. adults aged 60 years and over. Aging Clin Exp Res. 2021;33:3269–3274. PubMed
8. Zheng T, et al. Characterization of reduced astrocyte creatine kinase levels in Alzheimer’s disease. Glia. 2024;72:1590–1603. doi:10.1002/glia.24569
9. Jett S, et al. Effects of sex and APOE ε4 genotype on brain mitochondrial high-energy phosphates in midlife individuals at risk for Alzheimer’s disease: a 31P-MRS study. PLoS One. 2023;18:e0281302. doi:10.1371/journal.pone.0281302
10. Song T, et al. Mitochondrial dysfunction, oxidative stress, neuroinflammation, and metabolic alterations in the progression of Alzheimer’s disease: a meta-analysis of in vivo magnetic resonance spectroscopy studies. Ageing Res Rev. 2021;72:101503. PubMed
11. Snow WM, et al. Sex-specific effects of chronic creatine supplementation on hippocampal-mediated spatial cognition in the 3xTg mouse model of Alzheimer’s disease. Nutrients. 2020;12:3589. doi:10.3390/nu12113589
12. Whitford T, et al. The cognitive effects of creatine supplementation in older adults and preclinical models of dementia: a scoping review. Ageing Res Rev. 2026;122:103317. PubMed
13. Kreider RB, Kalman DS, Antonio J, et al. International Society of Sports Nutrition position stand: safety and efficacy of creatine supplementation in exercise, sport, and medicine. J Int Soc Sports Nutr. 2017;14:18. PubMed
EDITORIAL NOTE: All citations verified against the primary source record. Do not start or change a supplement regimen without discussing your medical history, medications, and kidney monitoring with a qualified clinician. Educational content only; not a substitute for individual clinical judgement.
