Is HRT safe? What the research says now

If you were around in 2002, you probably remember the headlines. A major study linked hormone therapy to breast cancer, heart disease, and strokes. Two decades later, the picture looks different. The risks are real, but they depend heavily on who takes hormones, when, and how. Here is what the research says now, in plain language.

The short answer

Hormone therapy is the most effective treatment for hot flashes, night sweats, and vaginal symptoms of menopause, and it has been shown to prevent bone loss and fracture ^[1]. Its risks differ by type, dose, how long you use it, the route, when you start, and whether a progestogen is part of it ^[1].

The Menopause Society's 2022 position statement puts it this way: for women younger than 60, or within 10 years of menopause, who have no reason they should not take it, the benefit-risk ratio is favorable for treating bothersome hot flashes and preventing bone loss ^[1]. For women who start more than 10 years after menopause or after 60, the balance appears less favorable, because the absolute risks of heart disease, stroke, blood clots, and dementia are higher ^[1].

So "is HRT safe?" does not have a yes-or-no answer. A better question is: is HRT a reasonable choice for me? That is a conversation for you and your clinician.

What the WHI found, and why it scared everyone

The Women's Health Initiative (WHI) was a large trial funded by the US government. Its estrogen-plus-progestin arm enrolled 16,608 postmenopausal women aged 50 to 79 ^[2]. Half took a daily pill combining conjugated equine estrogens and medroxyprogesterone acetate, and half took a placebo ^[2].

In 2002 the trial was stopped early, after 5.2 of a planned 8.5 years, because health risks exceeded benefits by a small margin ^[2]. Here is what researchers projected per 10,000 women taking the combination compared with placebo:

Those are small numbers in absolute terms. The Menopause Society notes that absolute risks, like these, are more useful than relative risks for weighing benefits and harms ^[1]. A separate WHI trial tested estrogen alone in women who had had a hysterectomy ^[1].

What changed since 2002

Researchers kept following WHI participants for years and looked more closely at who was in the study. A few things became clearer.

Age and timing matter

The average WHI participant was 63, well past the typical age of menopause ^{[1, 3]}. When researchers looked at women who were 50 to 59 when they started, the combined WHI trials showed lower all-cause mortality compared with placebo ^[1]. In that age group, neither combination therapy nor estrogen alone increased cancer deaths or cardiovascular deaths after a median of 18 years of follow-up ^[1]. Women who start hormone therapy after 60, or more than 10 to 20 years after menopause, have higher absolute risks of heart disease, blood clots, and stroke ^[1].

The type of hormone matters

The WHI tested one oral formulation ^[1]. Estrogen alone and estrogen plus progestin turned out to behave differently, especially for breast cancer (more on that below) ^[1]. Observational studies also suggest lower cardiovascular risk, including clots and stroke, with transdermal estradiol, lower doses, and different progestogens ^[1].

HRT is not for heart disease prevention

One message has stayed the same: hormone therapy is not approved for preventing heart disease ^[1]. It is used to treat symptoms and prevent bone loss.

The FDA's 2025 labeling changes

On November 10, 2025, the FDA announced it was beginning to remove the boxed warnings, often called "black box" warnings, about cardiovascular disease, breast cancer, and probable dementia from menopausal hormone therapy labels ^[3]. The agency pointed to the WHI participants' average age of 63 and the fact that they took a formulation no longer in common use ^[3]. In February 2026, the FDA approved the first updated labels, for six products across four categories of hormone therapy ^[4].

This does not mean the risks went away. The FDA did not ask companies to remove cardiovascular disease and breast cancer risks from the Warnings and Precautions section of the label ^[5]. It also kept the boxed warning for endometrial cancer on systemic estrogen-alone products ^{[3, 5]}. The FDA's labeled recommendation is to start systemic HRT within 10 years of menopause onset or before age 60, with timing and duration decided between you and your prescriber ^[3].

HRT and breast cancer

This is the risk most women worry about. Here is what The Menopause Society reports ^[1]:

• Estrogen plus progestin: in the WHI, the added risk was less than one additional breast cancer diagnosis per 1,000 users per year ^[1]. The Society compares this to the risk tied to two alcoholic drinks a day, obesity, or low physical activity ^[1].
• Estrogen alone: in women who had a hysterectomy, estrogen alone was linked to fewer breast cancer diagnoses and fewer breast cancer deaths than placebo after a median of 20 years of follow-up ^[1].
• Duration: in a large pooled analysis of observational data, breast cancer risk rose the longer hormones were used ^[1].
• Route: oral and transdermal estrogen appear to have similar effects on breast cancer diagnoses, while low-dose vaginal estrogen does not appear to affect it ^[1].

Your personal and family history matters too. The Menopause Society says personal and family risk of breast cancer should be considered before starting ^[1]. Hormone therapy is generally not advised for women who have had breast cancer ^{[1, 6]}.

Blood clots and stroke: route matters

Both estrogen alone and estrogen plus progestin carry a rare increased risk of venous thromboembolism (blood clots in the legs or lungs) ^[1]. How you take estrogen may change that risk.

• Pills: in a large UK study of more than 80,000 women with blood clots, oral hormone therapy was associated with a higher risk of clots compared with no hormone therapy ^[7].
• Patches, gels, and other skin forms: in the same study, transdermal hormone therapy was not associated with a higher clot risk ^[7]. The Menopause Society agrees that observational data point that way, but notes that randomized trials comparing routes are lacking ^[1].
• Progestogen choice: micronized progesterone may be less likely to promote clots than other progestins ^[1].

For stroke, the attributable risk in WHI women who started before 60 or within 10 years of menopause was rare ^[1]. Observational studies suggest lower doses of oral or transdermal estrogen may carry less stroke risk, but there are no head-to-head trials ^[1]. Women who started hormone therapy later had a higher risk of stroke and clots ^[1].

Read more about the transdermal route in our estradiol patch guide.

Protecting the uterus

If you still have a uterus, estrogen on its own makes the uterine lining grow, which raises the risk of endometrial hyperplasia and cancer ^[1]. That is why the FDA kept the endometrial cancer boxed warning on systemic estrogen-alone products ^[3]. Women with a uterus who use systemic estrogen should also take an adequate progestogen ^[1]. When that is done properly, the risk of endometrial cancer is not higher than in women not taking hormones ^[1].

Call your clinician about any unexpected vaginal bleeding while on hormones. To learn more, see progesterone side effects.

Memory and dementia

Dementia was one of the risks the FDA moved out of the boxed warning ^[3]. Older labels, like the Climara label, still describe a WHI finding of increased risk of probable dementia in women who were 65 or older when they began estrogen ^[6]. The Menopause Society notes that dementia is one of the risks that weighs more heavily for women who start hormones after 60 or more than 10 years past menopause ^[1]. It also says hormone therapy should not be used in older women to reduce the risk of heart disease or dementia ^[1].

The benefits you are weighing

Safety is only half of the decision. The other half is what hormone therapy may do for you. According to The Menopause Society ^[1]:

• Compared with placebo, estrogen alone or with a progestogen reduced weekly hot flash frequency by about 75% in pooled studies ^[1].
• Hormone therapy has been shown in randomized trials to prevent bone loss and reduce fractures ^[1].
• Frequent hot flashes lasted an average of 7.4 years in a large US study, and for many women more than 10 years ^[1].
• For vaginal dryness and related symptoms alone, low-dose vaginal estrogen is an option that may be considered at any age ^[1].

Benefits may also include better sleep, well-being, and quality of life ^[1]. For a woman whose sleep and work are being disrupted by hot flashes, those benefits count. For a woman with mild symptoms and a high personal risk, the balance may tip the other way. That is why the decision is individual.

Who should not take HRT

The Menopause Society and FDA labels list situations where systemic hormone therapy is not recommended ^{[1, 6]}:

• Unexplained vaginal bleeding
• Current or past breast cancer, or another estrogen-sensitive cancer
• A past heart attack, stroke, or coronary heart disease
• Current or past blood clots, or an inherited clotting disorder
• Liver disease
• A known allergy to the medicine

Other parts of your history can shape the decision too. For example, hormone therapy carries a rare increased risk of gallbladder disease ^[1]. Your clinician looks at your full history.

How long can you take HRT?

There is no set stopping age. The Menopause Society says an arbitrary age-based stopping rule is not clinically appropriate, and that hormone therapy does not need to be routinely stopped at 60 or 65 ^[1]. Longer use should be for a documented reason, like persistent hot flashes, with shared decision-making and regular check-ins on benefits and risks ^[1]. As you get older, using the lowest effective dose and a non-oral route may become more important ^[1].

What about compounded hormones?

"Bioidentical" can describe both FDA-approved and compounded hormones. FDA-approved estradiol and micronized progesterone are regulated and come with full prescribing information ^[1]. Compounded hormones are prepared by a pharmacy from a prescription ^[1]. Compounded drugs are not FDA-approved, so the FDA does not review their safety, effectiveness, or quality before they are marketed ^[9].

The FDA recommends FDA-approved hormone therapy and says it does not have evidence that compounded "bioidentical" hormones are safe and effective ^[8]. The Menopause Society says compounded hormones may be considered in some situations, such as an allergy to an ingredient in an approved product or a dose not available commercially ^[1]. It also says salivary and urine hormone tests are unreliable for dosing ^[1].

Talking through HRT with WarriorBabe Health

WarriorBabe Health clinicians review your health history before deciding whether hormone therapy makes sense for you. Options include oral estradiol, an estradiol patch changed weekly, estradiol cream, and a progesterone capsule for women with a uterus. You can compare them on our hormone treatments page.

Our hormone products are compounded by a licensed pharmacy. They are not FDA-approved, and FDA-approved versions of estradiol and progesterone also exist. Ask your clinician which is the better fit for you.

Curious whether HRT could be an option? Take the 2-minute quiz. A licensed clinician makes the final call on whether any prescription is appropriate.

This article is for general information. It is not medical advice and does not replace a visit with a licensed clinician who knows your history. Do not start, stop or change a medication without talking to your clinician. If you think you are having a medical emergency, call 911.