Strength · CREA-STR-02 · v2
Across nine small randomised trials, creatine tended to raise average power and blunt the drop-off across repeated sprints, with the clearest signal in trials that gave creatine on its own ([2], [6], [1]). Several formulations that combined creatine with other ingredients also beat placebo ([5], [8], [3]). But the picture is mixed: some trials found no sprint-power benefit at all, including one where muscle creatine clearly rose yet power did not ([4]), and others testing creatine alongside caffeine or taurine ([7], [9]). Even a clean creatine-only trial found peak power unchanged, with gains only in later-sprint average power ([2]). The panel read the corpus as genuinely net-positive for average power and fatigue resistance, but modest, uneven, and muddied by body-mass gain and combination designs.
Creatine-alone arms improved mean power and reduced fatigue across repeated sprints: [2] found mean power up 4.5% in the second half of the sprints with body mass up 0.99 kg, and [6] found peak power up 5.2% with performance decrement reduced 17.4% in the creatine-only group. The creatine arm in [1] raised absolute mean power across three consecutive Wingate tests, and combination formulations added benefit over placebo in [5] (4% peak, 5% mean power), [8] (better total time, average and max power) and [3]. Against this, [4] found no change in peak or mean power despite muscle creatine rising 18.8 mmol/kg, and [7] and [9] reported no between-group sprint-power difference. The effect is concentrated in mean power and fatigue resistance rather than peak power. The contested point: The division is whether the benefit extends to high-intensity peak power or is confined to later-sprint mean power and fatigue resistance: [2] explicitly left peak power unchanged, and [4], [7] and [9] found no repeated-sprint power gain. The combination designs [5], [8], [7] and [9] cannot isolate creatine monohydrate, so part of the positive signal is not cleanly attributable to creatine alone.
All 9 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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Four trials ([5] electrolyte, [8] magnesium chelate, [7] caffeine, [9] taurine) co-administer creatine with other agents, so their performance gains cannot be attributed to creatine monohydrate alone.
Direct nulls on the exact outcome: [4], [7] and [9] report no repeated-sprint power improvement; [4] is decisive because muscle creatine demonstrably rose yet power did not.
Where it remains uncertain. Direct nulls counter the signal — [4] saw no power change despite muscle creatine rising, and [7] and [9] found no between-group sprint-power difference — while [2] found peak power unchanged.
Aleatory
N ranges 12-60 per trial; arm-level creatine groups are often 7-12 participants ([7] n=7 per arm, [9] N=12), so true effects are estimated with wide uncertainty.
Epistemic
[5] (electrolyte), [8] (magnesium chelate), [7] (caffeine) and [9] (taurine) do not isolate creatine monohydrate, so their gains cannot be assigned to creatine alone.
Inferential
[2] found peak power unchanged with benefit only in later-sprint mean power, so the 'high-intensity' component of the claim is inferred from mean-power and fatigue data rather than peak power.
The load-bearing papers from a corpus of 9, each classified by what it does to the claim. Every DOI is taken from the corpus the claim was graded on.
Creatine-alone arm raised mean power across consecutive Wingate tests
“CR exhibited increased AMP across all three trials.”
Panel auditInternal validity: medium · scope of inference: Acute loading effects on repeated Wingate power in young trained-age males.Key limitations: very short 4-day protocol · benefit concentrated in combined CRCHO/CRCPS arms · many comparisons vs baseline not vs placebo
Cleanest creatine-alone evidence of improved repeated-sprint mean power; notes peak power unchanged
“Cr supplementation improved the mean power and speed in the second half of a repeated sprint running protocol, despite the increased body mass.”
Panel auditInternal validity: medium · scope of inference: Repeated treadmill sprint power in recreationally active males.Key limitations: small sample · benefit limited to mean power in second half, not peak power
Direct null: creatine raised muscle creatine but not repeated-sprint power in vegans/vegetarians
“There were no observed changes in peak and mean power output during repeated sprints.”
Panel auditInternal validity: medium · scope of inference: Short-term creatine loading in vegans and vegetarians, who start with lower muscle creatine.Key limitations: small sample · specific vegan/vegetarian population · only 7-day supplementation
3 of 9 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.
Net-positive primary RCT evidence for mean power and fatigue resistance supports the claim at Likely, held below Established by heterogeneity, combination-design confounds and several direct nulls.
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.
Isolated creatine-monohydrate peak-power effect. The positive combination trials ([5], [8]) confound creatine with co-ingredients, and the cleanest creatine-only trial [2] found peak power unchanged, so the peak-power half of 'high-intensity' rests on weak isolation. The panel rates this the highest-importance open gap for the claim, and names the study design that would close it: Adequately powered double-blind RCT of creatine monohydrate alone versus placebo with peak and mean power as co-primary repeated-sprint outcomes.
Open question: Does creatine monohydrate alone improve peak power in repeated high-intensity sprints? Why it is still open: The only clean creatine-only isolation, [2], found peak power unchanged, while peak-power gains ([5], [6], [8]) come from combination or multi-arm designs.
Priors is a sceptical first reader, not peer review, and not medical advice.
Release 2026-q4 · graded 21 Oct 2026 · protocol v0.19