Recent research suggests that hormone replacement therapy (HRT), used to manage menopause symptoms, might reduce the risk of dementia in some women. However, experts say more data is needed to confirm this link definitively. Menopause marks a significant shift in a woman's hormonal balance, as the ovaries produce less estrogen and progesterone. Scientists believe this decline may increase the risk of dementia, potentially making brain cells more vulnerable to aging and diseases like Alzheimer’s. Estrogen, a key hormone affected by menopause, is known to influence brain function. It acts as a neuromodulator, affecting how neurons communicate and helping them maintain their structure. Studies in mice have shown that a loss of estrogen can lead to a decrease in dendritic spines — small structures on neurons that help receive signals. Researchers also think estrogen may prevent the buildup of harmful proteins linked to Alzheimer’s, such as amyloid beta and tau, which form toxic clumps in the brain. Another potential benefit of estrogen is its role in sleep. Menopausal women often experience disrupted sleep due to hot flashes and insomnia. Estrogen can help reduce these symptoms, potentially improving the quality of sleep. Good sleep is important for the brain to clear out harmful proteins, and poor sleep has been linked to an increased risk of Alzheimer’s disease. HRT comes in two main forms: estrogen-only and combined estrogen-progesterone. Its use became popular in the 1990s but declined after a major study in 2002, called the Women's Health Initiative, found increased risks of certain diseases. However, more recent research has re-evaluated some of those findings. A study published in Neurology in August found that estrogen-only HRT was associated with a lower risk of dementia and better cognitive outcomes in some women. However, other studies have shown conflicting results, and the timing of when HRT is started may be a key factor. Experts suggest that starting HRT earlier — during perimenopause, the period before menopause — might be more beneficial for brain health. A study published in Alzheimer’s & Dementia found that women who began HRT between the ages of 46 and 56 had a reduced risk of dementia. However, for most women who experience natural menopause, there is not enough evidence to recommend HRT solely for dementia prevention. For those who undergo surgical menopause — when the ovaries are removed — estrogen-only HRT may offer more specific benefits due to the abrupt loss of hormones. Currently, HRT is not prescribed primarily to prevent dementia but to alleviate menopause symptoms. To better understand how HRT affects brain health, scientists are calling for more rigorous clinical trials that track women through the transition from perimenopause to postmenopause. Such studies could provide clearer insights into the role of HRT in protecting against dementia.