Does hormone therapy protect the heart? What the SWAN study found

You want relief. You also want to understand your heart risk.

You are taking hormones for hot flashes, or wondering whether to start. Then you see a headline suggesting they could help your heart. Does that change the decision for you?

A study published September 8, 2026, in JAMA Internal Medicine followed women with hot flashes, night sweats, or both. Starting menopause hormone therapy was linked to an estimated 22% lower risk of problems such as heart attack, stroke, and heart failure.

That is worth understanding. It does not prove hormone therapy prevents heart disease, and the authors specifically warn against prescribing it for that purpose on the basis of this study.

What did the study actually find?

Researchers studied 2,737 women in the Study of Women’s Health Across the Nation, known as SWAN. They were approaching menopause or had recently reached it, and had hot flashes or night sweats. When they entered the analysis, none had known heart or blood-vessel disease or had previously used menopause hormone therapy.

During the study’s twenty-year follow-up period, 755 women started hormone therapy that works throughout the body, rather than only in the vagina. It contained estrogen, sometimes paired with a hormone used to protect the lining of the uterus. This is called systemic hormone therapy.

Researchers counted 224 problems overall, including heart attacks, strokes, heart failure, procedures to restore blood flow, and deaths from heart or blood-vessel disease. Women reported the problems they survived. Death certificates were used to identify the causes of death.

The 22% figure compares how quickly these problems occurred in the two groups during follow-up. It does not mean 22 fewer women out of every 100 had a problem, or that taking hormones would lower your personal risk by 22%.

Timing appeared to matter.

Among women who started within ten years of menopause, the estimated risk was 27% lower compared with women who did not start therapy. As with the 22% figure, this is a comparison between groups, not a promised benefit for one woman. Starting more than ten years after menopause showed no clear benefit, and that result was less certain.

When you start belongs in the conversation, along with which treatment you take and why. This finding does not prove that starting earlier protects the heart or that everyone within ten years of menopause should take hormones.

The link with lower risk was strongest among Black women. Researchers did not find a clear link in White women or the other groups they studied. These smaller-group findings need more research. They are not enough to make treatment decisions based on race.

Why can’t this prove that hormones protect the heart?

This was not a randomized trial. Researchers did not assign women to take hormones or avoid them. They compared women who had already made those treatment choices, using a method designed to make the groups as comparable as possible.

The groups could still differ in ways the study could not fully account for, such as their health, access to care, other medicines, or reasons for choosing treatment. Those differences may explain some of the result.

Women’s reports of their health problems may also have been incomplete or mistaken. That is another reason to be careful about what the study can tell us.

Then why does this study matter?

This study adds information about women with symptoms around menopause. It does not erase earlier research or settle the benefits and risks of taking hormones for years. Your symptoms, health history, and stage of menopause still matter.

During those same years, your blood pressure, cholesterol, blood sugar, sleep, and what your body can comfortably do may be changing. Hot flashes do not mean you have heart disease. They can be a reason to bring those pieces into one conversation.

Two studies. Different questions.

Update added September 30, 2026. A Danish study published in The BMJ on September 23, 2026 looked at women aged 50–69. Researchers compared the hormone treatments women were using with their chance of a first blood clot in a vein, stroke from blocked blood flow, or heart attack.

Hormones taken by mouth were linked to more blood clots in veins. Most treatments delivered through the skin did not show more of the problems studied. There was one exception: more heart attacks were linked to a treatment using estrogen through the skin with a second hormone added for part of each cycle. This is called combined cyclic treatment.

The study found links; it could not prove that hormones caused those problems. It also could not prove that any treatment was free of risk.

The BMJ study did not include women who had already had a blood clot in a vein or artery. It cannot tell us which treatment is right after a clot, heart attack, or stroke.

SWAN asked about starting hormones in women with hot flashes or night sweats. They had no known heart or blood-vessel disease when they entered the study. The BMJ study asked about the treatments women were using and specific health problems. The studies add different information; neither headline should decide your treatment.

Sources: 1, 6

What does this mean for your own hormone decision?

Begin with the symptom you want to treat. Then discuss your age, when menopause began, and any history of heart problems, blood clots, breast disease, or problems involving your uterus or ovaries. Whether you have a uterus also affects which hormones you may need to protect its lining.

How you take hormones matters. A patch, a pill, and a low-dose vaginal treatment do not all work in the same way. This study looked at treatment that works throughout the body. It cannot tell you which product is right for you.

A history of heart attack, stroke, blood clots, certain cancers, unexplained vaginal bleeding, or liver disease can change whether systemic hormone therapy is appropriate. Discuss these with your clinician. Do not start, stop, or change hormones because of a headline.

Hormone therapy also does not replace treating high blood pressure, cholesterol, diabetes, or other risks to your heart and blood vessels. Those parts of the story still need their own attention.

The HEART RESERVE takeaway

Bring when your symptoms started, the hormone treatment you use or are considering, your blood-pressure and cholesterol results, and your pregnancy and family history. Your treatment decision should fit those details together.

Build your free Heart Story to gather those details before your appointment. It gives you one summary to help explain what changed and what you want to ask next.