Estrogen-only hormone therapy linked to lower dementia risk
According to new research, use of estrogen-only hormone therapy later in life was associated with a lower risk of dementia and fewer signs of Alzheimer’s disease.
August 12, 2026
*Reviewed by Sarah Song, MD, MPH, FAAN
Key takeaways
- In this study, women who used estrogen-only hormone therapy were less likely to have signs of Alzheimer’s disease in the brain after death.
- Estrogen-only hormone therapy use was also linked to a lower chance of a dementia diagnosis and fewer problems with memory and daily function.
- The study shows an association but does not prove that hormone therapy during menopause prevents dementia.
In a study published August 12, 2026, in Neurology®, researchers looked at medical records of more than 21,000 women age 50 and older. Some had used estrogen-only menopausal hormone therapy while others had not.
Menopausal hormone therapy is sometimes used to treat menopause symptoms such as hot flashes or night sweats. Estrogen-only therapy is usually prescribed only for people who have had a hysterectomy—a surgery to remove the uterus.
Researchers looked at several measures of brain health, including memory tests, dementia diagnoses, brain scans, blood and spinal fluid tests, and brain tissue examined after death (brain autopsy). Among women who had brain autopsies, those who had used estrogen-only hormone therapy were less likely to have signs of Alzheimer’s disease.
The study also found that women who used hormone therapy weren’t as likely to receive a dementia diagnosis or show symptoms of memory problems or decline in daily function.
These findings may help researchers better understand how estrogen use for menopause is connected to brain health. But the study cannot prove that estrogen-only hormone therapy prevents dementia.
The researchers also note that the women in the study who used hormone therapy were older (average age 70), which is different from the current standard practice of starting hormone therapy in the late 40s to early 50s and stopping before age 60.
More research is needed before doctors can make recommendations about hormone therapy for brain health.
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