The effect of exogenous ketone bodies on cognition across health and disease: a systematic review and meta-analysis.
Level 1 - systematic review of randomized trials
Systematic review and meta-analysis of randomized controlled trials.
PubMed 42063954 · doi:10.3389/fnut.2026.1802531
What was done
Authors conducted a systematic review and meta-analysis of randomized controlled trials identified from PubMed, Web of Science, and Embase through October 2025, adhering to PRISMA guidelines. The trials investigated the effects of exogenous ketone (EK) supplementation on cognitive performance in healthy adults or individuals with neuropsychiatric disorders. Quality was assessed using the PEDro scale. Random-effects models calculated standardized mean differences (SMD), and subgroup/meta-regression analyses assessed formulation type, duration (acute vs. intermediate), daily dose, population type, and acute cognitive stressors.
What was found
The review included 38 studies (41 protocols, 1,602 participants), with 29 protocols (1,117 participants) pooled in the meta-analysis. EK supplementation was associated with a statistically significant improvement in cognitive performance versus placebo (SMD = 0.29, 95% CI 0.16–0.41, p < 0.001). Subgroup analyses showed no significant differences by supplement type (p = 0.083), duration (acute vs. intermediate; p = 0.11), population (healthy vs. Alzheimer's disease; p = 0.077), or presence of acute cognitive stressors (p = 0.89). Meta-regression identified a positive association between daily EK dose and cognitive improvement.
Why it matters
This review provides quantitative evidence that exogenous ketone supplementation can modestly enhance cognitive performance across diverse populations without requiring dietary carbohydrate restriction.
Limits
The abstract does not provide specific data on individual cognitive domains assessed, exact dosing numbers, adverse events, or long-term clinical efficacy beyond intermediate durations. Several subgroup comparisons (such as supplement formulation and population type) demonstrated near-significant trends that may reflect limited statistical power rather than true equivalence.
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