Many women turn to menopausal hormone therapy (MHT) for help managing symptoms like hot flashes and night sweats. Now, two new studies suggest the treatment may provide another major benefit: potentially lowering their risk of dementia.

The evidence is far from conclusive—and even a little confusing, since some previous studies have reached the exact opposite finding.12

“We need more research…and to be cognizant of what’s proven and what’s still to be determined,” said Jennifer Bruno, PhD, who researches brain science at Stanford University and co-authored one of the new studies, which was published in Neurology.3

Right now, MHT is not proven to boost brain health. But since around two-thirds of Americans with Alzheimer’s are women, “we definitely want to follow through on these findings” and learn more, said Manisha Parulekar, MD, a brain health specialist at Hackensack University Medical Center who previously trained as an OB-GYN and was not involved in the new studies.

What the New Studies Found

Both new studies —Bruno’s and another published in Alzheimer’s & Dementia — suggest women who take hormones may have better cognitive health as they age.4 But they took different approaches to get there.

The Alzheimer’s & Dementia study drew on data from more than 183,000 post-menopausal women enrolled in a large, long-running trial in the U.K. Researchers monitored their health for around 13 years.

During that time, almost 4,000 of the women were diagnosed with dementia—and those who’d used some form of MHT were about 10% less likely to be in that group, compared with women who hadn’t.

Bruno and her team, meanwhile, wanted to go beyond dementia diagnoses and actually study the brains of women who’d used MHT, as that’s the “gold-standard” way to assess Alzheimer’s. They examined health and autopsy data from several hundred deceased women who’d used estrogen-only hormone therapy and several thousand who hadn’t.

Estrogen users had about 35% lower odds of developing Alzheimer’s-related brain changes, relative to women who hadn’t used MHT, they found.

Estrogen plays a crucial role in brain health, and its natural nosedive after menopause—and particularly early-onset menopause—has been linked to dementia. “We have a really strong theoretical reason to think [hormone replacement therapy] should be beneficial,” Bruno said.

Yet another recent study also found that MHT containing a form of estrogen, plus progesterone, may ease menopause-related brain fog, further reinforcing the theory that estrogen has cognitive benefits.5

And What The New Studies Couldn’t Find

A word of caution: These studies don’t definitively prove that MHT protects the brain, said Emily Griffin, MD, an OB-GYN with Oregon Health and Science University who wasn’t involved with the new research.

Both studies on MHT and dementia were observational. They compared people who developed dementia with those who didn’t, then looked for factors that may have influenced those outcomes. That approach uncovers patterns, Griffin explained, but it can’t prove cause and effect.

Plus, the studies didn’t fully account for all the nuances of hormone therapy, such as when each person started treatment and the exact dose and formulation they used. Those distinctions matter, Griffin said.

They may also help explain why research on this topic has been all over the map, with some studies finding cognitive risks and others finding benefits tied to MHT, Parulekar said.

For example, an influential early 2000s trial that found an increased risk of dementia focused on women who started taking estrogen plus progestin therapy when they were at least 65 years old. Studies of younger women and those taking estrogen-only therapy have generally come to more positive results.67

What This Means for Women

When Griffin’s patients ask if they should take MHT to protect their brains, she tells them the same thing she told HEALTH: “We don’t have evidence, at this point, that this will be preventative medicine for you.”

“We’re not there yet,” Parulekar agreed. The field needs more rigorously designed trials before doctors can explicitly recommend MHT to help prevent dementia.

But that doesn’t mean there’s no reason to take hormones. On the contrary, “I am very pro-estrogen,” Griffin said. It can make a huge difference for people struggling with menopause symptoms including hot flashes and night sweats, and it may strengthen bone health to boot.8

Talk to your doctor about whether MHT is right for you, Griffin said. It’s generally not recommended for women at increased risk of certain cancers, or those starting treatment after age 65.910 And if you still have a uterus, you’ll need to use an estrogen plus progesterone formulation, as estrogen-only medications may increase the risk of uterine cancer, Griffin said.

Finally, don’t forget that there are plenty of other ways to protect your brain, including managing chronic conditions, exercising, and staying socially active, Parulekar said. “There are so many other things that we can do,” she said. “We want to make sure we’re not bypassing that.”