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Hormone Therapy for Menopause: Risks and Benefits

Hormone therapy for menopause has real benefits and real risks, and how they balance depends on you: your age, how long since your last period, your health history, and the type, dose and route of hormones. This page sets out the hormone therapy risks and benefits plainly, so you can weigh them with our physician-led team in Aurora.

Medically reviewed by Amber Bocknek, MD, CCFP, ABAARM, FAAMM, MSCP, Medical Director, November 4, 2026

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Why do so many women worry about hormone therapy?

If you’ve ever typed “is HRT safe” into a search bar at 2 a.m., you’re in good company, and your caution makes sense. In July 2002, headlines around the world linked hormone therapy to breast cancer, heart attacks and strokes. Prescriptions dropped almost overnight, and a generation of women learned to see hormones as dangerous.

Dr. Amber Bocknek was in practice when those results came out. Hormone therapy had been a large part of her practice, with framed literature on its benefits on the wall of every treatment room. When the study was published, she took her patients off their hormones and took that literature down. She calls it a very big transition. It’s also why we treat your questions about risk as serious questions, and answer them with numbers rather than reassurance.

What did the Women’s Health Initiative actually find?

The Women’s Health Initiative (WHI) enrolled more than 27,000 U.S. women aged 50 to 79, with an average age of about 63. Women with a uterus took one specific pill, oral conjugated equine estrogen plus a synthetic progestin called medroxyprogesterone acetate, or a placebo. Women who’d had a hysterectomy took the estrogen alone or a placebo. The question was whether hormones could prevent chronic disease, not how well they treat symptoms.

For every 10,000 women taking the combined pill for a year, the 2002 results showed about 8 more invasive breast cancers, 7 more heart events, 8 more strokes and 8 more blood clots in the lungs, along with 6 fewer colorectal cancers and 5 fewer hip fractures. After 18 years of follow-up across both WHI hormone trials, deaths from any cause were essentially the same: 27.1% of women assigned to hormones and 27.6% of women assigned to placebo.

Those findings still stand. They apply most directly to the women who were studied: older, on average, and starting one oral regimen many years after menopause.

How to read the numbers: relative risk versus absolute risk

Headlines usually report relative risk: how much a risk goes up, as a percentage. Absolute risk tells you how many people are actually affected. Both are true, and they feel very different.

Think of a weather forecast. If the chance of rain tomorrow rises from 4 in 100 to 5 in 100, a headline could say rain is “25% more likely.” In real life, that’s one extra rainy day out of a hundred. Hormone therapy research works the same way, which is why we translate percentages into real numbers of women, such as how many out of 1,000, before you decide anything.

Hormone therapy risks: what the research shows

Think of hormone therapy risk less like a light switch and more like a dimmer. The type of hormone, the dose, the route (pill, patch or gel), how long you take it, when you start and your own health history each turn the dial up or down. The Menopause Society’s 2022 position statement says exactly this: risks differ by type, dose, duration, route, timing and whether a progestogen is used.

Breast cancer

Estrogen combined with a progestogen is linked to a small increase in breast cancer risk that grows with longer use. Over more than 20 years of WHI follow-up (the pills themselves were taken for about 5 years), women assigned to the combined pill had about 45 breast cancers per 10,000 women per year, compared with 36 on placebo. That’s roughly 1 extra case per 1,000 women per year. Estrogen alone, in women who’d had a hysterectomy, was linked to fewer breast cancers: about 30 versus 37 per 10,000 women per year.

Large observational studies also find more breast cancer risk with combined therapy than with estrogen alone, rising with duration. A 2019 analysis in The Lancet estimated that 5 years of estrogen plus a daily progestogen, started at 50, may add about 1 breast cancer for every 50 users by age 69, compared with about 1 in 200 for estrogen alone. Vaginal estrogen was not linked to added risk.

Blood clots and stroke

Estrogen taken by mouth passes through the liver first, where it can affect clotting factors. Observational studies consistently find a higher risk of blood clots in the legs or lungs with oral estrogen, especially in the first year, while estrogen through the skin (a patch or gel) has not shown the same rise. Stroke follows a similar pattern: oral hormone therapy carries a small increase, and studies of lower-dose patches have not shown one.

These are observational findings, not head-to-head trials, so we weigh them alongside your own clot history, family history and other risk factors.

The lining of the uterus

If you still have a uterus, estrogen on its own can overstimulate the lining and raise the risk of endometrial cancer. That’s why a progestogen is added: it protects the lining, and it needs to be the right type at the right dose.

Other risks to know

Gallbladder disease was more common with hormone therapy in the WHI.

Dementia was more common in WHI women who started hormones at 65 or older. Hormone therapy isn’t prescribed to protect memory.

Side effects such as breast tenderness, bloating, headache, spotting and mood changes can happen, especially early on, and are reviewed with your physician.

What are the benefits of hormone therapy?

Hot flashes and night sweats: The Menopause Society describes hormone therapy as the most effective treatment for these symptoms.

Vaginal dryness, pain with sex and some bladder symptoms (genitourinary syndrome of menopause): low-dose vaginal estrogen has the strongest evidence. Learn more about bladder leaks after menopause.

Bone: hormone therapy prevents bone loss and lowers fracture risk while you take it. In the WHI, there were 5 fewer hip fractures per 10,000 women per year.

Sleep and quality of life: these often improve when they’ve been disrupted by night sweats.

What it isn’t for: Canadian and international guidelines don’t recommend hormone therapy to prevent heart disease or dementia.

Testosterone is a separate conversation with its own evidence. See testosterone for women.

Why do age and timing matter?

Timing is one of the biggest dials. The Menopause Society’s 2022 statement says that for women under 60, or within 10 years of menopause, with no reason to avoid it, the balance of benefits and risks is favourable for treating bothersome hot flashes and preventing bone loss. Starting more than 10 years after menopause, or after 60, the balance is less favourable, because the absolute risks of heart disease, stroke, blood clots and dementia are higher.

Canada’s SOGC menopause guideline (No. 422a, 2021) and its patient site, Menopause and U, take the same individual approach: the decision is yours, and it’s reviewed with your provider at least once a year.

Who may not be a fit for hormone therapy?

The Menopause Society lists these as reasons systemic hormone therapy (pills, patches or gels that act on the whole body) is generally not advised:

unexplained vaginal bleeding

active liver disease

a past estrogen-sensitive cancer, including breast cancer

past heart disease, heart attack or stroke

a past blood clot, or a personal or inherited high risk of clots

If one of these applies to you, you still have options, including non-hormonal treatments for hot flashes, and your physician walks through them with you.

What about compounded or bioidentical hormones?

Several Health Canada-approved products, such as estradiol patches and gels and micronized progesterone, are bioidentical. Compounded preparations are made by a pharmacy for one person. They are not Health Canada-approved, so they haven’t been through the same testing for strength, purity and safety. Guidelines recommend approved products where possible; when we suggest a compounded preparation, your physician explains why.

How we personalize the decision at Thrive!

Symptoms tell us something is changing, but they don’t tell us why. So before we talk about hormone therapy, we look at the whole picture:

your symptoms, cycle history and goals

your personal and family history of cancer, blood clots, heart disease and stroke

comprehensive blood work, including an advanced lipid profile (apolipoprotein B and lipoprotein(a)), fasting blood sugar, insulin and A1C, liver and kidney function, thyroid and hormone levels

Alongside your blood work and symptoms, an at-home metabolite test shows how your body makes and processes hormones. It gives your physician more insight for personalizing your care, and it can be particularly useful in more complex cases.

Then we match the type, dose and route to you, and we keep reviewing it. We review your results with you in the context of your symptoms, history and goals. See personalized testing at Thrive! and our Personalized Hormone Program™ for women. Return to our menopause care hub.

Talk it through with our physician-led team

You don’t have to make this decision from a headline. Our physician-led team, led by Medical Director Amber Bocknek, MD, sets out the benefits and risks for you, in numbers that make sense, and helps you decide what fits your life. We see patients in Aurora and by virtual visit anywhere in Ontario.

Thrive! is private-pay and does not bill OHIP. Before testing, we tell you which lab tests carry a fee. Our hormone and menopause care is complementary, functional medicine care, which is uninsured. It works alongside your family doctor or nurse practitioner and doesn’t replace them, so we encourage you to keep them.

Also called: HRT, menopausal hormone therapy, hormone replacement therapy, MHT, estrogen therapy

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FAQ

What is hormone replacement therapy?

Hormone replacement therapy (HRT), also called menopausal hormone therapy, uses estrogen to ease symptoms caused by falling hormone levels. Women who still have a uterus also take a progestogen to protect its lining. It comes as pills, patches, gels and vaginal products. It’s used for hot flashes, night sweats, vaginal and bladder symptoms, and to prevent bone loss. Your physician helps you weigh whether it fits your situation.

Is hormone replacement therapy safe?

There isn’t a one-word answer, because the risks and benefits depend on you. Your age, how long since menopause, your health history, and the type, dose and route of hormones all change the balance. Known risks include blood clots, stroke and, with combined therapy, a small rise in breast cancer risk. Known benefits include relief of hot flashes and protection of bone. A physician reviews both with you.

Does hormone therapy cause cancer?

Estrogen combined with a progestogen is linked to a small increase in breast cancer risk that grows with longer use: in the WHI, about 1 extra case per 1,000 women per year. Estrogen alone, after a hysterectomy, was linked to fewer breast cancers in the WHI, although large observational studies suggest a smaller increase with longer use. In women with a uterus, estrogen without a progestogen raises the risk of endometrial cancer, which is why a progestogen is added.

Will hormone therapy cause weight gain?

A Cochrane review of randomized trials found that hormone therapy doesn’t cause extra weight gain beyond what’s typical around menopause. Midlife weight change has several causes, including shifting hormones, lost muscle, poorer sleep and changes in how the body handles insulin. That’s why we look at metabolic blood work and body composition, not just the number on the scale.

When should hormone replacement therapy be started?

Timing is an individual decision made with your physician after a review of your symptoms and health history. The Menopause Society reports that for women under 60, or within 10 years of menopause, with no reason to avoid it, the balance is favourable for bothersome hot flashes and bone protection. Starting later, the balance is less favourable. Hormone therapy isn’t used to prevent heart disease.