Estrogen

At one time estrogen was viewed as a possible method to prevent or treat Alzheimer's disease. Initial studies looked hopeful. Estrogen had been cited as promoting neural growth, synapse formation, increasing cerebral blood flow and as a possible antioxidant. Sadly any benefits seen in animal research did not translate into human treatment.

There were a number of studies that showed variable results. Research had linked decreased levels of estrogen with an increased risk of Alzheimer's disease, and in others, a decreased risk of Alzheimer's for women taking Hormone Replacement Therapy (HRT).

Then a number of large long-term trials showed that women who took estrogen or estrogen-progesterone had an increased risk of developing dementia. They also had increased risk of stroke, heart attack and high blood pressure.

In March 2004 the National Institutes of Health (NIH) stopped the estrogen only treatment section of the Women’s Health Initiative (WHI). It had been the largest-ever clinical trial investigating the risks and benefits of hormone replacement therapy. Estrogen appeared to increase the risk of stroke.

Estrogen is now only used short term for the treatment of menopausal symptoms. The potential benefits of estrogen for Alzheimer's disease have been outweighed by the side effects that now also include breast and ovarian cancer.