Is hormone therapy safe? What the evidence says in 2026

For a healthy woman under 60, or within 10 years of her last period, who has bothersome hot flashes or night sweats, hormone therapy is considered safe enough that its benefits outweigh its risks. That is the conclusion of The Menopause Society and ACOG, and in 2025 the FDA revised its labeling to reflect the same view. “Safe” does not mean risk-free: systemic estrogen slightly raises the chance of blood clots and gallbladder disease, combined therapy slightly raises stroke and breast cancer risk after several years, and the picture is less favorable for women who start later in life.

Why this question is so confusing

Most of what people believe about hormone therapy risk traces to one 2002 announcement. The Women’s Health Initiative (WHI) stopped its estrogen-plus-progestin trial early because of more breast cancers, heart attacks, strokes, and clots than placebo. The participants were mostly over 60; only about 30 percent were in their 50s, the age at which women actually seek treatment for symptoms. Later analyses by age told a different story, but the headline stuck. We explain the trial in The WHI study explained.

Relative risk versus absolute risk

A “26 percent increase” in breast cancer sounds large. Whether it matters depends on how common the event is to begin with. The Menopause Society uses a standard scale: an adverse effect is “rare” if it occurs in fewer than 1 in 1,000 women per year, which is fewer than 10 per 10,000. By that definition, every serious risk of hormone therapy in women under 60 falls in the rare range.

The numbers, by outcome

The Cochrane review of 22 randomized trials (43,637 women, mostly over 60) expressed risks as events per 1,000 women. For relatively healthy postmenopausal women on combined continuous therapy:

Outcome	Without hormone therapy	With estrogen plus progestin	Time frame
Coronary event	2 per 1,000	3 to 7 per 1,000	After 1 year
Blood clot (VTE)	2 per 1,000	4 to 11 per 1,000	After 1 year
Stroke	6 per 1,000	6 to 12 per 1,000	After 3 years
Breast cancer	19 per 1,000	20 to 30 per 1,000	After 5.6 years
Gallbladder disease	27 per 1,000	38 to 60 per 1,000	After 5.6 years
Any fracture	111 per 1,000	79 to 96 per 1,000	After 5.6 years

Estrogen alone, for women without a uterus, raised clot and stroke risk, did not raise coronary risk at any point, and lowered fracture risk. In the subgroup of women aged 50 to 59, the only risk that reached statistical significance was blood clots with combined therapy, and the absolute risk stayed below 1 in 500. The reviewers’ conclusion: women with intolerable symptoms “may wish to weigh the benefits of symptom relief against the small absolute risk of harm.”

Why age at starting matters

The WHI’s own 13-year follow-up summarized all adverse outcomes in a “global index.” Per 10,000 women per year, estrogen plus progestin produced 12 excess events in women aged 50 to 59 and 38 in women aged 70 to 79. Estrogen alone produced 19 fewer events in the 50 to 59 group and 51 excess events at 70 to 79. Neither regimen changed overall death rates, and younger women on estrogen alone had more favorable results for heart attack and mortality.

That gradient is why every US guideline anchors on age and time since menopause. The Menopause Society’s 2022 statement: a favorable balance under 60 or within 10 years of menopause; less favorable beyond that, because of the greater absolute risks of coronary heart disease, stroke, clots, and dementia at older ages.

Why the route matters

Oral estrogen passes through the liver first, which affects clotting factors. Transdermal estradiol in a patch, gel, or spray does not. A study of 80,396 UK women with a first blood clot, matched to 391,494 controls, found:

Preparation	Adjusted odds of blood clot vs. no use
Any oral hormone therapy	1.58
Oral conjugated equine estrogen plus medroxyprogesterone (the WHI regimen)	2.10
Oral estradiol plus dydrogesterone	1.18
Transdermal estradiol (patch or gel)	0.93 (no increase)

Guidelines therefore say transdermal estradiol is generally preferred when clot risk is elevated, while noting that no randomized trial has compared routes directly. Micronized progesterone may also be less clot-promoting than synthetic progestins. More in our guide to the estrogen patch.

What the FDA changed in 2025 and 2026

For more than twenty years, every systemic estrogen product has carried a boxed warning based on the WHI. On November 10, 2025, after a review of the literature, an expert panel, and public comment, the FDA asked all manufacturers of menopausal hormone therapies to:

• remove cardiovascular disease, breast cancer, and probable dementia from the boxed warning
• remove the instruction to use the lowest dose for the shortest time
• add that therapy may be considered for moderate to severe hot flashes in women under 60 or within 10 years of menopause
• keep the boxed warning for endometrial cancer on systemic estrogen-alone products

Cardiovascular and breast cancer risks remain in the Warnings and Precautions section of systemic products. The probable-dementia warning, based on WHI data in women who started therapy at 65 or older, was removed entirely. The FDA approved the first six revised labels on February 12, 2026, across combination, estrogen-alone, progestogen-alone, and vaginal products, with others following. Professional societies supported the change while continuing to stress that systemic estrogen carries risks that rise with age.

Practically, the label change affects what you read in the package insert. The evidence itself did not change in 2025; the label caught up with it.

Who should not use systemic hormone therapy

The Menopause Society lists these contraindications: unexplained vaginal bleeding; liver disease; a prior estrogen-sensitive cancer, including breast cancer; prior coronary heart disease, heart attack, stroke, or venous clot; and a personal or inherited high risk of clotting. Women with these histories have nonhormonal options, which we list in how to talk to your doctor.

How long is it safe to continue?

The WHI tested 5 to 7 years of use, so randomized data beyond that are limited. Observational data show breast cancer risk with combined therapy rises with duration. Guidelines do not set a stopping age: The Menopause Society says therapy does not need to be routinely discontinued at 60 or 65, that extended use should be for a documented reason such as persistent symptoms, and that risks should be reviewed periodically, with the lowest effective dose and a transdermal route becoming more important with age.

Questions to ask

• Where do I fall on age and years since my last period, and how does that change my risk?
• Do I have any contraindication to systemic estrogen?
• Would a patch or gel be a better choice than a pill for me?
• Which progestogen, and does the choice affect breast cancer or clot risk?
• How will we review this, and when?

To prepare, our symptom check gives you a one-page summary to bring, and our OB-GYN directory lists clinicians by city.