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LONGEVITY LATEST · DEEP DIVE ISSUE 36 COMPANION · 11 NOVEMBER 2026
LONGEVITY LATEST · DEEP DIVE
The Brain Is Last in the Queue
Why the everyday creatine dose may do far less for your brain than for your muscles, who might be the exception, and the blood test it can fool.
By Christian Thomsen · Companion to Issue 36 · 11 November 2026 · ~7-minute read
Production: confirm the Issue 36 web URL (linked twice below) once the issue is published.
I assumed creatine reached the brain the way it reaches muscle. Take it, the stores fill, job done. The trials kept quietly saying otherwise. Not that it never gets there. That it arrives late, in small amounts, and most clearly when the dose is pushed far beyond anything people take with breakfast.
That matters, because “good for your brain” is now half the reason people buy the tub. Issue 36 graded creatine for thinking a C in rested adults and a narrow B after a night without sleep. This piece explains why, and what it means for you.
Which row is yours
Most readers fit more than one row. Where two rows disagree, follow the more cautious one; the rest of the article explains the reasoning.
If you… | What the evidence supports | What it doesn’t |
Are 40–60, eat meat, sleep fine | Taking it for muscle. For memory, at most a small, uncertain effect at 5 g. | Counting on a brain benefit you would notice. |
Lift weights, at any age | 3–5 g a day. This is the A-grade use, and the reason to take it. | Treating lean tissue on a scan as all new muscle. |
Eat little or no meat | One small 2011 trial found a memory benefit only in vegetarians. | An extra edge: a larger 2023 trial found vegetarians did no better. |
Work shifts or lose sleep often | In two small lab trials, one large dose softened some of a single night’s decline. | Routine high doses, or real shifts. Nobody has tested either. |
Are over 60 and watching your memory | The most promising group in pooled data. | Protection. No controlled trial in healthy older adults shows slower decline. |
Have kidney disease or a flagged blood test | A conversation with your doctor first; see the blood-test section below. | Starting on your own, or assuming the test is wrong. |
Notice where the clearest signals come from: brains under strain, after a lost night or with disease, rather than rested ones.
Why the brain is different
Muscle takes its creatine from the blood, so when blood levels rise, muscle stores climb. The brain carries the enzymes to make its own, and its main way in from the bloodstream is a transporter known as SLC6A8. One explanation, offered by Hamilton Roschel, Bruno Gualano and colleagues in a 2021 review, is that the astrocytes wrapped around the blood–brain barrier carry little of it. Muscle gets served first; the brain waits at a narrow counter.
In the studies they reviewed, using 2 to 20 g a day for one to eight weeks, nine of 12 found brain creatine rose, by roughly 5–10% on average: about half the rise seen in muscle. Brain creatine is measured with magnetic resonance spectroscopy, and a 2026 conference abstract from Manchester Metropolitan University warns that most supplementation studies don’t report how reproducible their scans are. Some of a 5% rise could be noise.
The dose problem
The clearest brain effects came at doses three to five times the usual 5 g: 20 g a day in the Kansas Alzheimer’s pilot, and single doses of roughly 25 g and 14 g in the Jülich sleep trials. Those sleep trials hint at what creatine does in the brain. A night awake drains its energy reserves; in the 2024 trial, creatine shifted the brain’s high-energy phosphate chemistry on the scanner, and memory and processing held up better for several hours.
The 2026 repeat is a useful brake. At the lower dose, several tests improved, but after correcting for the number of tests, only one logic measure clearly held. And neither trial is a home protocol: the authors warned against trying it.
For the brain, creatine looks less like a daily upgrade and more like a reserve it may draw on when demand spikes.
One result cuts the other way. A 2025 trial in 36 perimenopausal and menopausal women reported a rise in frontal brain creatine on just 1.5 g a day of creatine hydrochloride. With nine women per group, and scan error of the size the Manchester group describes, I’d file it under “needs repeating”, not as proof that small doses of a pricier form work better.
Smith et al. Alzheimer’s Dement TRCI (2025) · Gordji-Nejad et al. Sci Rep (2024) · Gordji-Nejad et al. Nutrients (2026) · CONCRET-MENOPA trial. J Am Nutr Assoc (2025)
Who might be the exception
Vegetarians, probably not. Most dietary creatine comes from meat and fish, so vegetarians should have the most to gain. A 2011 trial by David Benton and Rachel Donohoe, 121 young women on 20 g a day for five days, found a memory benefit only in vegetarians. But a larger, preregistered 2023 trial by Sandkühler and colleagues, 123 adults on 5 g a day for six weeks, found vegetarians did no better than meat-eaters, and the overall effect was small at most.
Older adults. Older adults were the one group where the memory effect stayed significant after the double-counting was corrected. The trials also disagreed with each other more than anywhere else: a lead, not a verdict.
Middle-aged adults on a bigger dose. A 2026 Texas A&M trial gave 45- to 65-year-olds 10 g a day for 12 weeks and reported improvements on some cognitive measures, alongside lean-tissue gains and a rise in leg-press strength even in people who didn’t exercise. The authors label the cognitive results exploratory, with no correction for multiple tests, and the senior author chairs the scientific advisory board of the company that supplied the creatine. Worth a proper trial, not a change of dose.
Women, possibly. In the 2026 sleep trial, women improved more than men on several tasks, but only in exploratory analyses, and the main model found no clear sex difference.
Benton & Donohoe. Br J Nutr (2011) · Sandkühler et al. BMC Med (2023) · Prokopidis et al. Nutr Rev (2023) · Citherlet. Front Nutr (2026) · Chun et al. J Int Soc Sports Nutr (2026) · Gordji-Nejad et al. Nutrients (2026)
The blood test it can fool
This is the practical bit rarely mentioned at the till. Part of the creatine you take breaks down into creatinine, and most labs use creatinine to estimate your kidney function: the eGFR on your results. The “e” stands for estimated. On creatine, creatinine can drift up and the estimate down without your kidneys changing at all.
The evidence supports that, within limits. A 2025 meta-analysis in BMC Nephrology found a small, mostly early rise in blood creatinine and no statistically significant difference in pooled filtration results. A 2026 review of 20 randomised trials and 786 people in the Journal of Renal Nutrition found the same pattern: creatinine up by about 0.13 mg/dL, with no significant difference in estimated filtration across the eight trials that reported it. That estimate was imprecise, though, and the authors called for trials lasting more than a year.
A high creatinine on creatine is a question, not a diagnosis.
So, before your next blood test, tell whoever orders it that you take creatine. If your eGFR comes back flagged, ask whether a cystatin C test could help interpret it: it estimates kidney function from a protein that muscle creatine doesn’t feed. And if you already have kidney disease, this is a decision for you and your doctor, not for a newsletter.
What would change the grades
Three trials would move this. First, a placebo-controlled version of the Kansas Alzheimer’s pilot (NCT05383833). If brain creatine and test scores rise against placebo, the C becomes a B for those outcomes; slower progression of the disease would need longer trials with clinical end points. Second, a sleep trial over several nights rather than one, at doses people could live with. Third, a memory trial of 5 g a day in healthy over-60s, analysed so that each person counts once. Until then, the brain grades stay where Issue 36 put them.
What this means for you
The plan itself, what to buy, how much and when, lives in this week’s issue. This piece answers a different question: whether that plan does anything for your head.
For readers in the table’s first row, the most likely answer is: a little, perhaps, and probably not enough to notice. Take creatine for your muscles and treat a brain benefit as possible but unproven. A night-shift worker or an over-60 has a better reason to hope than a rested 45-year-old, but no trial yet runs long enough to promise anything. Whichever rows you’re in, the blood-test conversation applies.
The most expensive part of the whole business is still the gym membership.
Your turn: reply and tell me which rows of the table you’re in, especially if you work nights or are over 60. The poll in this week’s issue decides whether kidney worries get their own Hype Check; your replies decide what the next brain issue covers.
This is the Issue 36 Deep Dive. Longevity Latest grades interventions like this every Wednesday: what works, what’s premature, and what’s just marketing. Next week’s issue returns to NAD+ boosters.
Sources and further reading
Evidence reviewed through 8 November 2026. Brain creatine figures come from magnetic resonance spectroscopy, which has wide error margins. The 5–10% average and the half-of-muscle comparison are from Roschel et al., summarising earlier work. The Alzheimer’s pilot was single-arm and assessed feasibility, brain creatine and cognitive scores. Benton and Donohoe’s Methods section reports 121 participants; the abstract says 128. Sandkühler et al.’s memory result narrowly missed significance (p = 0.064); a Bayesian analysis favoured a small benefit. In the 2026 Jülich trial, only the pooled logic result passed correction for multiple comparisons. In Chun et al., exercise group was self-selected; creatine versus placebo was randomised within each group. The CONCRET-MENOPA result is taken from the abstract. In the 2026 kidney review, the pooled eGFR difference was −5.2 mL/min/1.73 m² (95% CI −15.0 to 4.6). Educational content only; speak to your GP before taking creatine if you have kidney disease.