Estrogen, a vital hormone in the sex hormone group, has an essential role in regulating the menstrual cycle and promoting reproductive health in women. It influences gender characteristics and sexual behavior, as well as broader effects on the body such as cardiovascular diseases, bone fragility, and temperature regulation of the brain. 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 ongoing debate about the association between hormone replacement therapy and dementia due to various factors that can complicate large-scale studies. While there are potential benefits of estrogen therapy, it is crucial to consider individualized risk assessments before initiating any treatment due to associated risks like breast cancer, venous thrombosis, and cerebral infarction. Overall, estrogen’s impact on women’s health goes beyond reproductive function and encompasses numerous physiological and psychological aspects.