Estrogen, a sex hormone, plays a critical role in regulating the menstrual cycle and supporting women’s reproductive health. It also influences gender characteristics and sexual behavior, as well as having broader effects on the body. For instance, estrogen protects against cardiovascular diseases, bone fragility, and helps regulate brain temperature. Recent research from University College London suggests that estrogen may have a protective role in memory disorders, potentially reducing the risk of dementia. However, there is no consensus on the association between hormone replacement therapy and dementia due to complicating factors such as confounding variables and unreliable self-reported information. Moreover, the protective effects of estrogen may vary across different types of dementia. While estrogen has shown to be protective against vascular dementia, its impact on Alzheimer’s disease remains inconclusive. Despite these potential benefits, there are also risks associated with hormone therapy, including an increased risk of breast cancer, venous thrombosis, and cerebral infarction. Therefore, careful evaluation of an individual’s health profile and risk factors should be considered before initiating hormone therapy. Overall, estrogen’s influence on women’s health extends beyond reproductive function and encompasses various physiological and psychological aspects. Ongoing research aims to further understand the complex roles of estrogen in brain health and its potential impact on memory disorders.