Risks of Hormone Replacement Therapy and What You Should Know

The risks of hormone replacement therapy (HRT) depend heavily on your age, whether you still have a uterus, the type of hormones you take, and how you take them. For most healthy women under 60 who are within 10 years of menopause, The Menopause Society states that the benefits of hormone therapy outweigh the risks.

This guide explains each major risk in plain numbers, shows how the hormone type and delivery method change that risk, covers what happens after five years of use, and lists the steps that keep HRT as safe as possible for women, men, and transgender women.

What Are the Risks of Hormone Replacement Therapy?

The risks of hormone replacement therapy are blood clots and stroke, breast cancer, uterine (endometrial) cancer, heart disease when started late, and gallbladder disease. Each risk is tied to a specific form of HRT or a specific timing, which is why the same treatment can be low risk for one woman and higher risk for another.

• Blood clots and stroke: Estrogen pills raise the risk of deep vein thrombosis and stroke slightly, while patches, gels, and sprays do not raise blood clot risk, according to the NHS.
• Breast cancer: Combined estrogen and progestogen therapy slightly raises breast cancer risk over time, while estrogen-only therapy carries little or no increase.
• Uterine cancer: Estrogen taken without a progestogen thickens the uterine lining in women who still have a uterus, which raises endometrial cancer risk.
• Heart disease: Cleveland Clinic reports a higher heart disease risk when women begin HRT more than 10 years after menopause starts.
• Gallbladder disease: Cleveland Clinic lists a higher risk of gallbladder disease among the possible risks of HRT.

The size of these risks is small for most women. The NHS states that the risks of serious side effects from HRT are usually very low, and that older studies which made people afraid of HRT are now seen as out of date. Risk also sits alongside real benefits, including relief from hot flashes, protection against osteoporosis, and better muscle strength.

Weighing risk against benefit starts with the root cause of your symptoms. Hot flashes, night sweats, and mood shifts all signal hormonal imbalance during midlife, and the right plan depends on which hormones are driving them. Two of these risks draw the most attention.

What Is the Greatest Risk of Hormone Replacement Therapy?

The greatest risk of hormone replacement therapy is a blood clot from oral estrogen or a small rise in breast cancer risk from long-term combined therapy, depending on the form of HRT you take. Both risks are real, both are small in absolute terms, and both are shaped by choices you and your doctor control.

Blood clot risk comes mainly from estrogen pills. Maven Clinic reports that pills carry about a 60% higher rate of blood clots than patches or gels, because estrogen taken by mouth passes through the liver, and the liver responds by making more clotting proteins. The NHS states that HRT patches, sprays, and gels do not increase the risk of blood clots at all.

Breast cancer risk comes mainly from combined therapy used for years. The NHS reports around 5 extra cases of breast cancer in every 1,000 women who take combined HRT for 5 years. That risk depends on the hormone type and the delivery method, which is where most of the safety decisions are made.

How Do Hormone Type and Delivery Method Change HRT Risk?

Hormone type and delivery method change HRT risk because estrogen-only and combined therapy affect breast and uterine tissue differently, and pills affect clotting differently than patches, gels, and sprays. The table below compares the main forms of HRT side by side.

Every form in this table belongs to a wider family of options, and the types of hormone therapy available today give doctors far more ways to lower risk than they had 20 years ago.

Estrogen-Only vs. Combined HRT Risks

Estrogen-only HRT carries little or no increase in breast cancer risk but raises uterine cancer risk in women who still have a uterus, while combined HRT protects the uterus but brings a small rise in breast cancer risk over time. Maven Clinic reports that estrogen alone can at least double the chance of uterine cancer in women who still have a uterus.

Progestogen solves the uterine problem. The American Cancer Society notes that people who have a uterus should not take estrogen-only HRT, and that combined therapy is used because progesterone protects the uterus. The choice of progestogen matters too, since Maven Clinic reports that research suggests body-identical progesterone may carry a lower breast cancer risk than older synthetic versions.

Oral vs. Transdermal Estrogen Risks

Oral estrogen carries a higher risk of blood clots and stroke than transdermal estrogen, because estrogen pills pass through the liver first while patches, gels, and sprays enter the bloodstream through the skin. The NHS reports that HRT tablets slightly increase stroke risk, though the risk stays very low, particularly for women under 60.

Doctors use this difference on purpose. Women at higher risk of blood clots are usually advised to use patches, sprays, or gels rather than tablets, according to the NHS. Route matters on day one, and time on therapy matters over the years that follow.

What Happens After 5 Years of HRT?

After 5 years of HRT, the small rise in breast cancer risk from combined therapy becomes measurable, while the risk from estrogen-only therapy stays little or none. The NHS reports around 5 extra cases of breast cancer in every 1,000 women who take combined HRT for 5 years.

Breast cancer risk follows a clear pattern. The NHS explains that the risk increases the longer you take combined HRT and the older you are, and that it falls again after you stop. Regular mammograms matter more while you take HRT for this reason.

Five years is also when some benefits become clearer. Bone protection builds with steady use, and women lose up to 20% of their bone density in the five to seven years after menopause without it, according to the National Osteoporosis Foundation. Age at the start plays just as large a role as years on treatment.

What Age Is Too Late for Estrogen?

The age that is too late for starting estrogen is generally after age 60 or more than 10 years after menopause, because heart disease, stroke, and clot risks rise when systemic HRT begins later. Dr. Julie Gralow, Chief Medical Officer at the American Society of Clinical Oncology, has explained that HRT risks are much lower for women under 60 or within 10 years of menopause than for women who start later.

Researchers call this pattern the timing hypothesis. Estrogen started near menopause acts on younger, healthier blood vessels, while estrogen started years later acts on vessels that may already carry plaque. The right moment to start hormone therapy is therefore close to the start of your symptoms. The timing hypothesis also explains why HRT gained such a frightening reputation in the first place.

Why Were Doctors Cautious About HRT?

Doctors were cautious about HRT because a large 2002 study from the Women's Health Initiative linked hormone therapy to breast cancer, heart disease, and stroke, and the FDA added a boxed warning to HRT products soon after. That study shaped prescribing for more than two decades.

The 2002 study had important limits. Maven Clinic reports that participants were 63 years old on average, well past the typical age of menopause, and that the study used an HRT formulation that is no longer in use today. The results did not reflect women who start HRT in their late 40s or early 50s.

Guidance has since been updated. The FDA announced on November 10, 2025, that it would remove most of the boxed warning from menopausal hormone therapy products. The American Cancer Society notes that this change does not mean HRT is safe for everyone, and that a boxed warning remains for estrogen-only products because of endometrial cancer risk. Many women now start HRT for perimenopause with a clearer picture of both sides. Even with low serious risk, most women do notice some early side effects.

What Side Effects Are Common on HRT?

The side effects that are common on HRT are irregular vaginal bleeding, breast tenderness, mood swings, bloating, nausea, and headaches. Cleveland Clinic reports that these side effects usually resolve on their own within a few months, and that most do not require stopping treatment.

Each side effect has a typical pattern. Maven Clinic reports that spotting is expected in the first three to six months, especially with daily combined therapy, that bloating and nausea are more common with oral estrogen, and that mood shifts and headaches are often linked to the progestogen part of combined therapy. Some women also ask about HRT and hair loss, since hair can shift as hormone levels change.

Mood changes deserve attention on their own. Support for emotional health helps while your body adjusts, and a change in dose or progestogen type often settles mood side effects. Most side effects and most serious risks respond to the same set of protective steps.

What Lowers the Risks of HRT?

The steps that lower the risks of HRT are starting before 60, choosing transdermal estrogen when clot risk is higher, adding a progestogen if you have a uterus, using the lowest dose that controls symptoms, keeping up with screenings, and reviewing your plan every year. Each step targets a specific risk.

1. Start in the right window. Begin HRT before age 60 or within 10 years of menopause, when the balance of benefits and risks is most favorable.
2. Choose the right route. Use patches, gels, or sprays instead of pills when you have a higher risk of blood clots.
3. Protect the uterus. Take a progestogen alongside estrogen if you still have a uterus.
4. Use the dose that controls your symptoms. Maven Clinic notes that higher-than-needed doses do not relieve symptoms better and only raise the chance of side effects.
5. Share your full history. Maven Clinic lists smoking, untreated high blood pressure, a strong family history of breast cancer, and certain migraine patterns as factors that raise risk.
6. Keep up with screenings. Attend every mammogram and gynecological exam while you take HRT.
7. Review every year. Check your plan annually with your doctor to confirm it still fits your health.

Lifestyle strengthens every step on this list. Not smoking, staying active, and building bone and muscle with strength training all lower long-term risk, and these habits sit at the center of anti-aging medicine.

Hormone balance also shapes how safely HRT works, since steady hormone balance depends on estrogen, progesterone, cortisol, and thyroid hormones working together. The same principles of dose, route, and health history also apply to hormone therapy for men.

What Are the Risks of Male Hormone Replacement Therapy?

The risks of male hormone replacement therapy are a high red blood cell count (erythrocytosis), which is the most consistent side effect, while large trials show no rise in heart attacks or strokes for men with confirmed low testosterone. Testosterone replacement therapy (TRT) is the main form of male HRT.

Heart safety was the biggest question for years. The TRAVERSE trial, published in the New England Journal of Medicine in 2023, followed 5,246 men aged 45 to 80 with low testosterone and found no difference in major cardiovascular events between testosterone and placebo. TRAVERSE also found no increased risk of prostate cancer over 33 months of follow-up.

Erythrocytosis is the risk doctors watch most closely. A review of the TRAVERSE data identified erythrocytosis as the most consistent side effect of testosterone therapy, which is why men on TRT need regular blood counts. Experts also stress that these safety findings apply only to men with documented low testosterone, not to men with normal levels. Men weighing their options can learn more about male hormone therapy and how testing guides it. Transgender women face a different set of considerations with estrogen.

What Are the Risks of Estrogen Therapy for Transgender Women?

The risks of estrogen therapy for transgender women are minimal for most healthy people, but blood clots, stroke, and heart attack risks rise with smoking, existing health conditions, or starting after age 50. UCSF Transgender Care reports that the biggest increase in risk comes from combining estrogen with cigarette smoking.

Delivery method matters here too. UCSF Transgender Care notes that estrogen delivered through the skin, such as a patch, is generally the safest option for people over 50 or with higher risk. UCSF also reports a small increase in gallstone risk, a possible slight rise in breast cancer risk that still stays below that of cisgender women, and possible mood swings during the early months.

Research in this group is still growing. UCSF Transgender Care notes that there is limited scientific evidence on long-term cancer risks in transgender women, so regular monitoring with an experienced provider is important. Across women, men, and transgender women, the same truth holds: risk is personal.

How Do You Weigh HRT Risks for Your Own Body?

You weigh HRT risks for your own body by reviewing your personal and family history, testing your current hormone levels, naming your most disruptive symptoms, and matching the hormone type and route to all three. The American Cancer Society notes that the decision to use HRT depends mainly on your personal health history and current health status.

Testing guides every decision in our approach. We use saliva adrenal testing along with blood work to measure hormone levels, and we review environmental toxic exposure, because many household and skincare products contain chemicals that disrupt hormones. Test results show whether estrogen, progesterone, cortisol, or thyroid hormones drive your symptoms.

Women across Oakland County come to us wanting clear answers instead of fear or guesswork. Dr. Doug Cutler built the Integrative Health Model™ to find the root cause first and then build a personalized plan that helps you balance hormones naturally, with hormone therapy as one option among several.

Frequently Asked Questions

Is It Better to Go Through Menopause Without HRT?

It is not better for every woman to go through menopause without HRT, because the right choice depends on your symptoms, age, and health history. The Menopause Society states that the benefits of hormone therapy outweigh the risks for most healthy women with symptoms who are under 60 and within 10 years of menopause. Women with a history of breast cancer, blood clots, stroke, or liver disease often do better with non-hormonal options.

How Does HRT Affect Weight and Belly Fat?

HRT does not cause weight gain and helps prevent belly fat from building up after menopause, according to a review by the International Menopause Society. Dr. Stephanie Faubion, medical director of The Menopause Society, has noted that hormone therapy is not a weight-loss drug. Nutrition and exercise still drive most weight change, and guidance on nutrition and weight helps many women on HRT.

Does Vaginal Estrogen Carry the Same Risks as HRT?

No, low-dose vaginal estrogen does not carry the same risks as systemic HRT. The NHS states that vaginal estrogen does not increase the risk of breast cancer, blood clots, or other conditions, because very little of it reaches the rest of the body, so it is safe to use for a long time.

Does HRT Increase Diabetes Risk?

No, HRT does not increase the risk of type 2 diabetes, according to the NHS, and some recent studies suggest it may even slightly reduce that risk.

What Can I Do Instead of HRT for Menopause?

You can use non-hormonal medicines, talking therapies, lifestyle changes, and vaginal moisturizers instead of HRT for menopause. The Menopause Society's 2023 nonhormone therapy statement gives its strongest support to cognitive behavioral therapy (CBT), clinical hypnosis, SSRIs, SNRIs, gabapentin, and fezolinetant for hot flashes.

Putting It All Together

The risks of hormone replacement therapy are real but small for most healthy women who start before 60, choose the right hormone type and route, and review their plan every year. Blood clot risk comes mainly from pills, breast cancer risk comes mainly from long-term combined therapy, and uterine cancer risk disappears when a progestogen protects the uterus. Men on testosterone and transgender women on estrogen follow the same rule: the right dose, route, and monitoring keep risk low.

Every woman's risk picture is different, and fear should never replace facts. Women in Bingham Farms and nearby communities do not have to make this decision alone. At Cutler Integrative Medicine, we are here to test, listen, and build a plan around your body, and you can reach out whenever you feel ready to start.