Short‑term feeding of a ketone monoester to 24‑month‑old male and female C57BL/6 mice raised post‑prandial β‑hydroxybutyrate and lowered glucose, but produced divergent effects on body composition, hippocampal inflammation and spatial memory that depended on sex.
Study and findings
In a randomized short‑term intervention, 24‑month‑old male and female C57BL/6 mice received a diet containing the ketone monoester (R)-3‑hydroxybutyl (R)-3‑hydroxybutyrate. The supplement raised post‑prandial β‑hydroxybutyrate (β‑HB) concentrations and reduced post‑prandial glucose relative to control diet. Male mice showed a shift in body composition, with reduced fat mass and a higher proportion of lean mass. Female mice displayed improved performance in the Barnes maze, reflected by fewer primary errors, and exhibited lower hippocampal interleukin‑1β (IL‑1β) expression. Tissue‑specific fasting metabolite profiling revealed sex‑dependent alterations, and hippocampal oxylipin patterns were also modified.
Clinical interpretation
The data indicate that ketone monoester supplementation can modulate systemic metabolism and brain‑related outcomes in aged rodents, but the direction of these effects is sex‑specific. In males, the primary benefit appears to be a favorable change in body composition, whereas in females the main observable advantage is a modest improvement in spatial learning and a reduction in a pro‑inflammatory cytokine within the hippocampus. These findings suggest that metabolic and neuroinflammatory pathways responsive to elevated β‑HB may be differentially regulated in male and female aging brains, a factor that could influence the design of ketone‑based interventions for older adults.
Limitations and open questions
The study is limited to a single short‑term dosing regimen in one mouse strain, and it does not assess long‑term safety, functional outcomes beyond the Barnes maze, or dose‑response relationships. Because only post‑prandial β‑HB and glucose were reported, the magnitude of chronic ketone exposure remains unclear. Translating these sex‑specific effects to humans will require controlled trials that consider hormonal status, age‑related metabolic changes, and potential interactions with diet. Moreover, the mechanisms linking ketone‑induced metabolic shifts to hippocampal oxylipin remodeling and IL‑1β suppression need further elucidation.
Source
Roslund KJ, Coates LC, Sattar Sultani S, Hayes D, Diaz S, Rutkowsky JM, et al. Ketone ester supplementation in aged mice produces sex-specific cognitive and metabolic effects. Geroscience. 2026. doi: 10.1007/s11357-026-02546-8. PMID: 42776386.