Cognition · CREA-COG-02 · v2
One controlled trial directly tested whether a single dose of creatine helps people whose thinking is impaired by going without sleep, and it found that creatine reduced the drop in performance on several mental tasks during a 21-hour period awake [1]. A second trial found creatine improved a cognitive test as well, but in men sleeping normally rather than sleep-deprived, so it only hints that the effect is plausible [7]. The rest of the corpus is not really about taking creatine for the mind at all; in most of those papers 'creatine' refers to a blood marker of muscle damage or the studies test other things entirely. So the direct support comes down to a single small study from one group, with nobody else in this evidence set having repeated it. The panel saw a real but thin signal, which is why it sat in the middle rather than treating the claim as well established.
A single double-blind, placebo-controlled RCT in twenty-nine healthy subjects directly tested 0.2 g/kg creatine monohydrate against placebo during 21 h of sleep deprivation and found a mitigating effect on deterioration in logical and numerical tasks, language-related processing speed, and the Psychomotor Vigilance Test, with an improvement of up to 12% [1]. That same trial reports females benefited more than males in several of those tasks [1]. A separate crossover RCT in 14 physically active men found 7-day creatine loading improved cognitive performance on the digit cancellation test (d = 0.77, p = 0.013), but under normal sleep, so it speaks to plausibility rather than the sleep-deprivation claim [7]. No study in the corpus independently replicates the sleep-deprivation-specific effect. The contested point: The division is whether one small, unreplicated RCT on short-window surrogate task scores [1], plus an out-of-context creatine-cognition result [7], is enough to support a broad statement about attenuating 'cognitive decline' from sleep deprivation. The direct evidence exists and is on-point, but its singularity, small sample, and reliance on task-level surrogates are what keep the claim from rising higher.
All 10 papers behind this claim with their DOIs and what each does to it, the panel’s arbitration, the evidence gap map and the open research questions. Free, and sent to your inbox.
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One reviewer's only job is to attack the finding. The challenges below were weighed before the grade was set.
The direct case rests on a single small RCT (n=29) from one group [1]; the corpus contains no independent replication of the sleep-deprivation effect, so evidential independence is minimal.
The claim's phrase 'cognitive decline' is broader than what [1] demonstrates: mitigation on specific tasks (logic, numerical, language processing speed, PVT) over a short window, not a general or durable cognitive-decline endpoint.
Where it remains uncertain. The direct case rests entirely on that one trial [1]; the only other creatine-cognition study has no sleep-deprivation condition [7], and the remaining papers use creatine merely as a muscle-damage biomarker.
Aleatory
The direct effect rests on 29 subjects [1], so chance variation around the estimate is large and uncontrolled.
Epistemic
No corpus study other than [1] tests the sleep-deprivation-specific effect; the prior 0.35 g/kg study it references is not in the corpus.
Inferential
[1] measures short-window task scores (logic, numerical, language speed, PVT over ≤7.5 h), not a general or durable cognitive-decline endpoint the claim implies.
The load-bearing papers from a corpus of 10, each classified by what it does to the claim. Every DOI is taken from the corpus the claim was graded on.
Direct primary evidence that creatine attenuates SD-induced cognitive deterioration across multiple domains.
“Our results show that a dose of 0.2 g/kg creatine is associated with a reduced deterioration in cognitive performance during sleep deprivation.”
Panel auditInternal validity: medium · scope of inference: Healthy adults undergoing 21 h of acute sleep deprivation, given a single 0.2 g/kg creatine dose.Key limitations: small sample · single acute dose only · no statistics reported in abstract · acute SD not chronic
Indirect support that creatine can improve a cognitive measure, but in non-sleep-deprived men; corroborates plausibility only.
“improved cognitive performance on the DCT ( d = 0.77; p = 0.013)”
Panel auditInternal validity: medium · scope of inference: Physically active men under normal conditions; creatine's effect on cognition, sleep metrics and performance without sleep deprivation.Key limitations: no sleep deprivation condition · small male-only sample · single cognitive test
2 of 10 papers shown. The full review lists all of them, with the panel’s arbitration →
Claims are graded at each quarterly release, and re-graded between releases only when a pivotal trial lands. Every change is a new version of the claim.
Direct but singular small-RCT evidence raises the claim above neutral yet is too thin and unreplicated to reach Likely.
Release 2026-q4 re-graded every claim from its corpus under protocol v0.19. An earlier release's grade is shown for the record; it came from an earlier protocol and is not a movement.
Assumptions that carry weight but are not themselves established.
The panel records the gap that would most move the claim, and the study that would close it.
No independent replication under sleep deprivation. The direct claim rests on one small RCT from a single group [1], so the effect's reality cannot be separated from one lab's result. The panel rates this the highest-importance open gap for the claim, and names the study design that would close it: A pre-registered multi-site double-blind placebo-controlled RCT replicating 0.2 g/kg creatine against placebo during comparable sleep deprivation with the same cognitive battery.
Open question: Does the sleep-deprivation-specific cognitive benefit of creatine replicate outside the single originating group? Why it is still open: Only one trial in the corpus tests it [1] and no independent study confirms it.
Priors is a sceptical first reader, not peer review, and not medical advice.
Release 2026-q4 · graded 21 Oct 2026 · protocol v0.19