Does HRT Affect Dementia Risk? The Largest Analysis Yet Says No

This December 2025 review set out to settle a genuinely confusing question, whether hormone therapy affects the risk of dementia, after years of conflicting claims in both directions. Restricting itself to the highest-quality evidence, randomised trials and prospective studies that followed women over time, and pooling data from more than a million participants, the researchers found no significant association between hormone therapy and the risk of mild cognitive impairment or dementia, in either direction. This directly addresses the decades-old fear rooted in an early 2000s trial of older women starting a different kind of hormone therapy well past menopause, and it equally corrects the newer, more hopeful claim that hormone therapy actively protects the brain. As the largest and most rigorous synthesis of this question to date, its conclusion carries real weight, though the authors note that longer, more targeted trials would still help, particularly for women with early menopause. For a woman deciding whether to start hormone therapy, it removes dementia, in either direction, as a reason to decide for or against it, leaving the choice to rest on the symptoms and other health factors that genuinely apply to her.