Ageing · CREA-AGE-02 · v2
Borderline: within 4 points of the Uncertain/Doubtful boundary, so a re-grade could land either side.
Several randomized trials tested creatine plus resistance training in older adults, and the results split. The largest and longest trial [1] found no effect on bone mineral density, the standard measure of bone health, and two other trials [3][6] were also null on density, while only the smallest early trial [5] showed a density benefit. A more consistent but modest signal appears on bone geometry and strength predictors such as section modulus and bone area [1][2]. Trials of creatine without resistance training [4][8] showed nothing, suggesting the resistance training does most of the work. No trial measured fractures, so the panel treated the claim as partly supported on geometry but not established on bone density.
The exact combination was tested in multiple blinded RCTs, with density outcomes mostly null: the 2-year N=237 trial [1] reported no effect on femoral neck, total hip or lumbar spine BMD, and [3] and [6] were likewise null on density. A density benefit appeared only in the smallest, shortest combination trial [5]. A replicated signal exists on geometric predictors: [1] maintained section modulus (P=0.0011) and buckling ratio (P=0.011), and [2] increased total bone area in the distal tibia (P=0.031) and tibial shaft (P=0.032). Trials of creatine alone [4][8] found no bone effect, isolating the supplement's contribution as null. The contested point: The division is between bone mineral density, which is null in the largest trial [1] and in [3] and [6] and positive only in the smallest [5], and bone geometry/strength predictors, which show a modest replicated benefit [1][2]. The dispute is whether a surrogate geometric signal, absent any fracture outcome, supports the general claim of improved bone health.
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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One reviewer's only job is to attack the finding. The challenges below were weighed before the grade was set.
The largest, longest RCT [1] (N=237, 2 yr) found no effect on BMD at the femoral neck, total hip or lumbar spine — the primary measure of bone health — so 'improves bone health' is an overreach.
The replicated positive signals are surrogate geometric predictors (section modulus, bone area) [1][2], not hard fracture outcomes; no fracture benefit is demonstrated for the combination.
Where it remains uncertain. BMD, the standard measure, is null in [1][3][6] and positive only in the smallest trial [5], and creatine-alone trials [4][8] are null, so any added benefit over resistance training rests on surrogate geometry [1][2] rather than density or fractures.
Aleatory
The sole positive BMD result [5] had 33 of 47 analyzed, a size at which a chance effect not reproduced in the larger [1] is plausible.
Epistemic
No trial measured fractures for the combination; [4] recorded falls and fractures but tested creatine alone and found no change.
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.
Largest/longest RCT of the combination finds no BMD benefit — weakens the general claim.
“Creatine significantly maintained section modulus (1.35 ± 0.29 to 1.34 ± 0.26 vs 1.34 ± 0.25 to 1.28 ± 0.23 cm 3 (placebo), P = 0.0011), predictive of bone bending strength”
Panel auditInternal validity: high · scope of inference: Postmenopausal women (mean 59 yr) doing resistance training plus walking, over 2 years; BMD vs geometric bone outcomes.Key limitations: BMD null but geometry favourable — divergent outcomes · lean-mass benefit only in completer subanalysis · women only
Supports a bone-area benefit of the combination.
“Compared with Pl, Cr increased or maintained total bone area in the distal tibia (Cr, Δ +17 ± 27 mm2; Pl, Δ -1 ± 22 mm2; P = 0.031)”
Panel auditInternal validity: medium · scope of inference: Men and women mean age 58 doing whole-body resistance training; bone area/density by pQCT at radius and tibia.Key limitations: mean age 58 — lower end of 'older' · effects site-specific (tibia only, not radius) · 'increased or maintained' conflates two outcomes
Null BMD result for the combination.
“Creatine supplementation, independent of the timing of ingestion, has no effect on aging bone mineral content or density.”
Panel auditInternal validity: low · scope of inference: Aging adults (~53-57 yr) on whole-body resistance training; BMC/BMD by DXA across whole body and axial/appendicular sites.Key limitations: very small groups · short duration for bone outcomes · powered around supplement timing, not overall efficacy
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.
A replicated geometric signal keeps the claim above Doubtful, but null BMD in the definitive trial and surrogate-only outcomes prevent it reaching 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 fracture endpoint for the combination. The claim concerns bone health, but every combination trial reports BMD or geometry, not fractures [1][2][3][5][6]. The panel rates this the highest-importance open gap for the claim, and names the study design that would close it: A large, long-duration RCT of creatine plus resistance training in older adults powered for incident fractures.
Open question: Does creatine added to resistance training reduce fracture incidence in older adults? Why it is still open: No combination trial in the corpus measured fractures; outcomes are limited to BMD and bone geometry [1][2][3][5][6].
Priors is a sceptical first reader, not peer review, and not medical advice.
Release 2026-q4 · graded 21 Oct 2026 · protocol v0.19