Metabolic syndrome and Alzheimer's disease (AD) are increasingly recognised as interconnected, sharing vascular, metabolic and inflammatory pathways that accelerate brain ageing and cognitive decline. This review critically examines the evidence that glucagon-like peptide-1 receptor agonists (GLP-1RAs), initially developed for diabetes and obesity, may influence AD related pathways or reduce AD risk in metabolically vulnerable populations. Metabolic syndrome and AD related cognitive impairment share biological mechanisms including vascular damage, insulin resistance and chronic inflammation, suggesting that therapies targeting metabolic dysfunction could influence neurological outcomes. GLP-1RAs are notable for combining systemic benefits, like weight loss, improved glycaemic control, and reduced cardiovascular risk, with possible but incompletely established central nervous system effects. Experimental studies suggest that some GLP-1RAs may reduce amyloid and tau pathology, support mitochondrial function, and limit neuroinflammation, although recent preclinical studies and limited brain penetrance argue against a direct neuroprotective effect. Observational data suggest lower dementia rates among users compared with other antidiabetic treatments. However, the recent EVOKE and EVOKE + trials showed that oral semaglutide did not slow clinical progression in early symptomatic AD, despite positive biomarker effects. This highlights the challenge of translating biological plausibility into meaningful clinical benefit and refocuses attention on disease stage, target population, and mechanism. Beyond summarising evidence, this review advocates a more cautious and mechanism specific framework: preserving cognitive health may require addressing systemic metabolic dysfunction rather than targeting the brain alone. GLP-1 RAs have failed to show an effect in symptomatic AD, but their effects on metabolism might still be beneficial at earlier stages, such as the preclinical phase of AD. Future studies should determine whether earlier intervention in metabolically enriched groups can alter AD related cognitive, vascular, and biomarker trajectories.
