The brain is deeply responsive to hormonal change. A January 2026 review summarizes growing evidence that estrogen decline — particularly in cases of early menopause or oophorectomy — is associated with long-term changes in brain health, including higher risk of neurodegenerative conditions such as Alzheimer’s disease. This matters because estrogen is involved in more than reproductive function. It plays a role in: • synaptic communication • mitochondrial energy metabolism • neuroinflammatory re