Alzheimer's disease (AD) is a complex neurodegenerative brain disorder that leads to severe cognitive impairments, particularly memory deficits, affecting millions of people worldwide. Currently, there is no effective therapy to halt or slow its progression. Poor dietary habits and lifestyle choices are major risk factors for AD, and metabolic dysregulation is commonly observed in individuals with the disease. Leptin, a crucial metabolic hormone, has been shown to possess cognitive-enhancing properties. Increasing evidence suggests that deficiencies and dysfunctions in leptin are associated with an increased risk of AD. Leptin not only improves the pathological features of AD but also significantly affects hippocampal synaptic function, exerting neuroprotective effects. Furthermore, leptin has shown promising prospects in the clinical treatment of AD, potentially serving as both a new therapeutic approach and a diagnostic tool.