For years, women have received conflicting messages about hormone therapy.
Some have been told estrogen is dangerous for the heart. Others have heard that hormone therapy may actually protect it. So which is true?
A new study published September 8, 2026, in JAMA Internal Medicine adds important information to the conversation, particularly for women going through perimenopause or who have recently reached menopause.
Researchers studied 2,737 women who had hot flashes or night sweats and had no history of cardiovascular disease. Over approximately 20 years of follow-up, women who started menopausal hormone therapy had an estimated 22% lower rate of cardiovascular events compared with women who did not start treatment.
The association appeared even stronger when hormone therapy was started within 10 years of menopause.
That sounds like a compelling argument for hormone therapy, but it is not that simple.
See Dr. Beth's video on this topic here.
The study was observational, not a randomized clinical trial. That means it can identify important patterns, but it cannot prove that hormone therapy caused the lower cardiovascular risk. In fact, the researchers specifically caution that these results should not be used to prescribe hormone therapy for the purpose of preventing heart disease.
So what should women actually take from this research?
The bigger lesson may be that when it comes to hormones, timing and individual health matter.
Why Has Hormone Therapy Been So Confusing?
To understand why this study matters, it helps to understand how dramatically the conversation around menopausal hormone therapy has changed.
Menopausal hormone therapy, or MHT, is used primarily to treat symptoms related to declining ovarian hormones during the menopause transition. These symptoms can include hot flashes, night sweats, sleep disruption, vaginal and urinary symptoms, and other concerns.
Hormone therapy generally involves estrogen. Women who still have a uterus typically also need progesterone or another progestogen to protect the uterine lining.
For many years, hormone therapy was widely prescribed during and after menopause. Then cardiovascular concerns changed the conversation.
Large randomized trials from the Women's Health Initiative raised concerns about cardiovascular and other risks associated with certain forms of hormone therapy in the women who were studied.
But there was an important issue. Many women in those early trials were considerably older than the women who typically begin hormone therapy for menopause symptoms today.
That raised another question: Does it matter when hormone therapy is started?
Researchers sometimes call this the timing hypothesis. The idea is that the effects of hormone therapy may differ depending on a woman's age, how long it has been since menopause, her cardiovascular health, and other individual factors.
The new study helps investigate that question.
What Did the Researchers Study?
Researchers used data from the Study of Women’s Health Across the Nation, commonly called SWAN.
SWAN is a long-running U.S. study that has followed women through the menopause transition.
For this analysis, researchers included 2,737 women who reported hot flashes or night sweats and had no cardiovascular disease or previous menopausal hormone therapy use. Of those women, 755 eventually started systemic hormone therapy.
Their average age when beginning treatment was about 54.
Researchers then looked at cardiovascular events over approximately 20 years. These included heart attack, stroke, heart failure, procedures to restore blood flow to the heart, and cardiovascular-related death.
The researchers used a statistical method called target trial emulation.
That sounds complicated, but the idea is fairly simple. When researchers cannot randomly assign people to a treatment, they can sometimes organize observational data in a way that tries to answer a question similar to the one a randomized clinical trial would answer.
It is a sophisticated method, but it does not turn an observational study into a randomized trial. That distinction matters.
What Did They Find?
Overall, women who initiated menopausal hormone therapy had an estimated 22% lower rate of cardiovascular events than women who did not initiate therapy.
Researchers then looked at timing.
Among women who started hormone therapy within 10 years of menopause, the estimated rate of cardiovascular events was lower than among women who did not start therapy.
The picture was different among women who started hormone therapy more than 10 years after menopause. In that group, the estimate did not show a clear cardiovascular benefit and was too imprecise to draw a firm conclusion.
This supports a growing idea in menopause medicine: hormone therapy may not have the same risk-benefit profile for every woman at every age.
Does This Mean Hormone Therapy Prevents Heart Disease?
No.
This is the most important takeaway from the study.
The authors themselves state that the results should not be used to support menopausal hormone therapy for cardiovascular disease prevention.
Why?
Because this was an observational analysis.
Women were not randomly assigned to take hormones or avoid them. That creates the possibility of confounding, which means another difference between the groups may partly explain the result.
For example, women who choose hormone therapy may differ from women who do not in ways that affect cardiovascular health. They may have different access to healthcare, health behaviors, socioeconomic circumstances, underlying health risks, or relationships with their physicians.
Researchers can use statistical methods to adjust for many known differences, but no statistical method can guarantee that every important difference has been accounted for.
This is why association and causation are not the same thing.
The study found an association between hormone therapy initiation and lower cardiovascular risk in this group of women. It did not prove that hormone therapy prevented those cardiovascular events.
What Does This Mean for Women Considering Hormone Therapy?
It means the conversation should be individualized.
Hormone therapy is primarily used to treat menopausal symptoms, not as a medication prescribed simply to prevent heart disease. But cardiovascular health still matters when deciding whether hormone therapy is appropriate.
A thoughtful evaluation may consider factors such as age, time since menopause, symptoms, blood pressure, cholesterol and lipoproteins, blood sugar regulation, smoking history, body composition, family history, previous cardiovascular events, clotting risk, migraine history, breast and uterine health, and other aspects of medical history.
The type of hormone therapy matters too.
Hormones can be given in different forms, doses, and combinations. For example, estrogen can be taken orally or delivered through the skin with a patch or gel. Women with a uterus generally need progesterone or another progestogen along with systemic estrogen.
These are not interchangeable decisions.
The appropriate approach depends on the individual.
Hot Flashes May Be More Than an Inconvenience
There is another interesting part of this research.
The study specifically focused on women with vasomotor symptoms, the medical term for hot flashes and night sweats.
These symptoms are extremely common during the menopause transition. They can interfere with sleep, concentration, mood, exercise recovery, and quality of life.
Researchers are also studying whether vasomotor symptoms may sometimes provide information about cardiovascular health.
That does not mean having hot flashes causes heart disease. It also does not mean a woman experiencing hot flashes should assume she has cardiovascular disease.
It means symptoms that appear during the menopause transition may provide another opportunity to look at the broader health picture.
Instead of treating menopause as an isolated reproductive event, it can be useful to think of midlife as a time to reassess cardiovascular, metabolic, bone, brain, and hormonal health together.
Menopause Happens During a Larger Physiological Transition
This matters because several things can change around midlife at the same time.
Body composition may shift. Muscle mass may decline. Visceral fat, the deeper abdominal fat around internal organs, may increase. Insulin sensitivity can change. Blood pressure and cholesterol may change. Sleep may become more fragmented. Bone loss can accelerate, while ovarian hormone production changes dramatically.
Not every change is caused by menopause. Aging itself matters. Lifestyle matters. Genetics matter. Medical conditions and medications matter.
But looking at these systems together can provide a much more useful picture than simply checking an estrogen level and deciding whether it is “normal.”
This Is Where Earlier Understanding Matters
A woman can feel relatively healthy while cardiovascular risk factors are beginning to change.
High blood pressure often causes no symptoms. Elevated LDL cholesterol usually causes no symptoms. Insulin resistance may develop before diabetes. Visceral fat can increase even when the number on the scale changes very little. Cardiovascular fitness can decline gradually, and bone loss can occur without pain.
That is why the absence of symptoms is not the same thing as the presence of optimal health.
Menopause can be an important moment to establish or update a baseline.
What is happening with blood pressure? What do lipid markers show? How is glucose regulation? What has changed in body composition? What is your cardiovascular fitness? How are you sleeping? What is happening with bone health? What symptoms are you experiencing?
And how do all of those pieces affect the risks and potential benefits of treatment?
At Jyzen, that broader context is central to the way we think about hormone health. The goal is not simply to raise a hormone level into a particular range. It is to understand the person.
The Bigger Lesson From This Study
For years, the hormone conversation was often reduced to two extremes: hormone therapy is dangerous, or hormone therapy is protective.
Neither is a useful way to practice individualized medicine.
The new JAMA Internal Medicine study adds to evidence suggesting that when hormone therapy is initiated may matter, particularly for women near the menopause transition. But it does not prove that hormone therapy prevents cardiovascular disease, and it does not change the need to consider each woman's overall risk-benefit profile.
That may be the most important takeaway.
The question is not simply, “Are hormones good or bad?”
A better set of questions is: What symptoms are we treating? Where are you in the menopause transition? What is happening with your cardiovascular and metabolic health? What are your individual risks? What form and dose of treatment makes sense, if treatment is appropriate at all? And what should we continue to measure over time?
Earlier understanding creates more choices.
And menopause is an important opportunity to understand not only hormones, but the health of the whole person.
This article is for educational purposes only and does not provide individualized medical advice. Menopausal hormone therapy is a prescription treatment with benefits, risks, and contraindications that vary by individual. Decisions about hormone therapy should be made with an appropriately qualified healthcare professional.
Primary source: Wang Z, Swanson SA, Brooks MM, et al. Menopausal Hormone Therapy and Cardiovascular Risk in Midlife Women With Vasomotor Symptoms. JAMA Internal Medicine. Published online September 8, 2026.