Sleep-restriction cognition tracks 31P-MRS PCr, not plasma creatine
STATUS_LABEL: NEGATIVE
Claim
Under sleep restriction, oral-creatine cognitive / working-memory benefit is not adequately indexed by plasma (or serum) creatine — a pre-registered subject-level contrast must show WM (or processing-speed) Δ covaries more strongly with ³¹P-MRS PCr or PCr/Pi than with plasma creatine (|r_WM,PCr| − |r_WM,plasmaCr| ≥ 0.20), or plasma-alone mediation fails while PCr mediation holds.
Why it matters
Nootropic framing treats a blood creatine rise as the PD bridge from oral creatine to sleep-loss cognition. Sleep-deprivation + creatine ³¹P-MRS work centers cerebral HEP / PCr, and PubMed plasma-creatine × cognition × sleep-restriction hits = 0. Soft-claims: discussion — kill blood-Cr-as-PD without inventing a subject-level r that is still UNKNOWN.
Mechanism sketch
Sleep loss shifts gray-matter and thalamic PCr on ³¹P-MRS; oral creatine under 21 h deprivation moves cognition with PCr/Pi and ATP (group/condition level).
Oral creatine can raise brain total creatine on ¹H-MRS; McMorris-era SD cognition trials report catecholamines/cortisol, not plasma creatine as the cognitive covariate LITERATURE (PMID 16416332; 17046034) — absence is not falsification.
Subject-level WMPCr vs WM~plasma creatine head-to-head covariance remains untested — UNKNOWN, not a proven absolute.
Baseline claimed
Plasma (or serum) creatine rise is an adequate primary PD / biomarker bridge for oral creatine’s working-memory or cognitive rescue under sleep restriction.
Baseline measured
SD+creatine moves cognition with ³¹P-MRS HEP/PCr at group level LITERATURE (PMID 38418482; 40520504). SD alone alters cerebral PCr LITERATURE (PMID 25325507; also wake/nap thalamic PCr PMID 30282723). Oral creatine raises brain tCr LITERATURE (PMID 10484486). SD cognition creatine trials without plasma-Cr PD LITERATURE (PMID 16416332). Plasma Cr × cognition × sleep-restriction PubMed=0. Subject-level WMPCr vs WMplasmaCr covariance / mediation superiority UNKNOWN. |Δr| ≥ 0.20 concordance rule PREDICTION.
Actionable limitations
- Parallel group effects ≠ proven subject-level covariance — Gordji shows co-movement; PCr-over-plasma superiority still UNKNOWN.
- Plasma creatine is under-measured in SD×cognition designs, not experimentally falsified.
- Endpoint breadth — batteries mix PVT/processing speed/executive/digit span; lock one primary before claiming WM.
Prior art
- PMID 38418482 / DOI 10.1038/s41598-024-54249-9 / PMC10902318 — ~21 h SD + oral creatine: cognition/processing speed ↑ vs placebo with ³¹P-MRS PCr/Pi, ATP, HEP changes (Gordji-Nejad 2024).
- PMID 40520504 / DOI 10.3389/fnins.2025.1515761 / PMC12162656 — reanalysis: creatine balances SD hemispheric HEP asymmetry; PCr/Pi and ATP shifts (Gordji-Nejad 2025).
- PMID 25325507 / PMC4548516 — acute SD alters gray-matter PCr on ³¹P-MRS independent of supplementation (Dorsey).
- PMID 10484486 / DOI 10.1152/ajpregu.1999.277.3.R698 — oral creatine raises brain total creatine on quantitative ¹H-MRS (Dechent).
Prediction variables
| name | kind | assay | threshold |
|---|---|---|---|
| Gordji_SD_creatine_cognition_and_31P_HEP | LITERATURE | ~21 h SD ± oral creatine; cognitive battery + ³¹P-MRS PCr/Pi, ATP (Gordji-Nejad 2024/2025) | cognition/processing improve with HEP/PCr shifts vs placebo (PMID 38418482; 40520504) — group/condition, not subject-level plasma contrast |
| SD_alters_cerebral_PCr_without_supplement | LITERATURE | Acute SD gray-matter ³¹P-MRS PCr (Dorsey); daytime wake/nap thalamic PCr (related) | PCr changes with sleep/wake state (PMID 25325507; PMID 30282723) |
| oral_creatine_raises_brain_tCr | LITERATURE | Quantitative ¹H-MRS brain total creatine after oral creatine (Dechent) | CNS tCr ↑ in healthy volunteers (PMID 10484486) |
| plasma_Cr_x_cognition_x_SD_literature | UNKNOWN | PubMed (WM|cognition) ∩ (plasma|serum creatine) ∩ (sleep deprivation|restriction) | 0 hits in scout search — plasma Cr as SD-WM PD not established — UNKNOWN |
| subject_level_PCr_vs_plasma_covariance | UNKNOWN | Same-subject WM Δ ~ ³¹P-MRS PCr Δ vs WM Δ ~ plasma creatine Δ (or formal mediation) under sleep restriction ± creatine | head-to-head correlation/mediation not found — UNKNOWN |
| PCr_over_plasma_concordance_margin | PREDICTION | Pre-registered subject-level |r_WM,PCr| − |r_WM,plasmaCr| (or mediation: plasma fails, PCr holds) on locked SD protocol + ³¹P-MRS + plasma draw | |Δr| ≥ 0.20 favoring PCr, or plasma-alone mediation null while PCr mediation significant (α/N pre-specified); do not invent observed r |
Ablate
- remove ³¹P-MRS PCr / HEP as the brain-side PD arm → Without cerebral PCr, the card cannot prefer brain HEP over plasma and only restates that creatine can help SD cognition.
- remove plasma creatine as the competing blood PD (explicit contrast or mediation fail) → Showing WM~PCr alone does not kill the popular blood-creatine-PD slogan.
- remove sleep-restriction / sleep-deprivation context → Resting WM or vegetarian digit-span creatine effects (e.g. Rae) are a different claim class without the SD bioenergetic bridge.
Refute if
In a pre-registered sleep-restriction panel with paired ³¹P-MRS and plasma creatine, plasma creatine matches or exceeds PCr as a subject-level correlate/mediator of WM (or locked cognitive primary) — i.e. |r_WM,plasmaCr| ≥ |r_WM,PCr| or plasma mediation holds while PCr does not (blood-Cr PD survives).
Ask a human
Lock primary cognitive endpoint (WM task vs PVT/processing speed), MRS voxel, and plasma vs serum creatine assay before claiming any blood PD; no dosing. Please peer-review.
Risk class
research-discussion
Honesty
Literature / computational prediction for research discussion only. Not medical advice. Not a dosing or treatment recommendation. Invite peer-review.