Understanding: What are the dangers of hormone therapy?

September 24, 2025 •

3 min read

According to the National Cancer Institute, systemic menopausal hormone therapy has potential harms, such as increased risks of stroke and blood clots. Understanding what are the dangers of hormone therapy is crucial for making an informed decision with your healthcare provider about its use.

Quick Summary

The dangers of hormone therapy include heightened risks for cardiovascular issues, blood clots, certain cancers, and potential side effects like bone density loss, mood changes, and weight gain, which vary based on the specific treatment and individual health factors.

Key Points

Cardiovascular Risk: Hormone therapy, especially oral forms, can increase the risk of heart attack, stroke, and blood clots, with higher risk factors including age and time since menopause.
Cancer Connection: Combined estrogen-progestin therapy increases breast cancer risk, while estrogen-only therapy increases endometrial cancer risk if a uterus is present.
Personalized Assessment: The level of risk from hormone therapy is highly dependent on individual factors like age, health history, and the specific type of treatment.
Bone Health: Certain cancer-related hormone therapies can weaken bones and increase the risk of osteoporosis and fractures.
Side Effects: Common side effects include fatigue, weight gain, mood swings, and changes in sexual function, which can be managed with professional guidance.
Risk Mitigation: Discussing options with a doctor, using the lowest effective dose, and adopting a healthy lifestyle are key to managing the risks of hormone therapy.

The Diverse Landscape of Hormone Therapy and its Risks

Hormone therapy (HT) is a medical treatment used for a variety of conditions, most commonly to manage the symptoms of menopause, treat certain cancers, or as part of gender-affirming care. While it can provide significant relief and therapeutic benefits, understanding the associated risks is crucial for any patient. The specific dangers of hormone therapy can differ depending on the hormones used, the dosage, the method of delivery, and the patient's individual health profile.

Cardiovascular Concerns: Heart Attack, Stroke, and Blood Clots

Research indicates potential links between certain types of HT and an increased risk for serious cardiovascular events. Starting HT more than 10 years after menopause or after age 60 may increase the risk of heart disease. Oral hormone therapy, in particular, is linked to a higher risk of developing blood clots in the legs and lungs. Transdermal delivery methods might carry a lower blood clot risk. {Link: cancer.gov https://www.cancer.gov/about-cancer/causes-prevention/risk/hormones/mht-fact-sheet}

Different types of hormone therapy can influence the risk of certain cancers, particularly those that are hormone-sensitive.

Long-term use of combined estrogen-progestin therapy is associated with an increased risk of breast cancer.
In patients with an intact uterus, estrogen-only therapy can increase the risk of endometrial cancer, a risk mitigated by taking progestin.
Some studies suggest a potential increase in the risk of ovarian cancer, though more research is needed.

Bone Health and Osteoporosis

While some hormone therapies for menopause can prevent bone loss, others used to treat hormone-sensitive cancers can weaken bones. For instance, androgen deprivation therapy for prostate cancer and aromatase inhibitors for breast cancer can lead to osteoporosis and increased fracture risk.

Common and Less Common Side Effects

Patients on hormone therapy may experience various side effects, including fatigue, weight gain, breast tenderness, headaches, mood swings, anxiety, depression, cognitive difficulties, and sexual side effects like changes in libido or vaginal dryness.

Comparison of Hormone Therapy Types: Risks and Benefits


Feature	Menopausal Hormone Therapy (MHT)	Hormone Therapy for Cancer	Gender-Affirming Hormone Therapy (GAHT)
Primary Goal	Symptom relief (hot flashes, night sweats), osteoporosis prevention.	Block or reduce hormones that fuel cancer growth (e.g., breast, prostate).	Align physical characteristics with gender identity.
Key Risks	Increased risk of breast cancer (combined), endometrial cancer (estrogen-only w/ uterus), blood clots, stroke.	Bone weakening (osteoporosis), cardiovascular issues, sexual dysfunction, mood changes.	Potential increased risk of cardiovascular issues and blood clots (feminizing), mood changes, infertility.
Benefits	Effective symptom relief, improved quality of life, bone density maintenance.	Control or shrink tumors, extend life for patients with hormone-sensitive cancers.	Reduce gender dysphoria, improve mental health, and physical well-being.
Risk Factors	Age, time since menopause, formulation (oral vs. transdermal), personal health history.	Specific type of cancer, duration of treatment, age, other health conditions.	Hormones used, individual health factors, duration of therapy.

Mitigating the Dangers with a Personalized Approach

Risk mitigation for hormone therapy involves a thorough consultation with a healthcare provider to evaluate personal and family medical history and existing conditions. Strategies include using the lowest effective dose for the shortest time needed, choosing administration methods like transdermal patches to potentially lower blood clot risk, regular monitoring through exams and screenings, and adopting a healthy lifestyle. {Link: cancer.gov https://www.cancer.gov/about-cancer/causes-prevention/risk/hormones/mht-fact-sheet}

For more in-depth information on the various types of hormone therapy and associated risks, consult authoritative sources such as the National Cancer Institute.

Conclusion: Weighing Risks vs. Benefits

Hormone therapy offers significant benefits but carries risks, including cardiovascular events, blood clots, cancer links, and side effects. A personalized approach guided by a healthcare professional is essential. {Link: cancer.gov https://www.cancer.gov/about-cancer/causes-prevention/risk/hormones/mht-fact-sheet}

Frequently Asked Questions

The most serious dangers include an increased risk of cardiovascular events like heart attack and stroke, as well as the potential for blood clots. There is also a link between certain hormone therapies and specific cancers, such as breast and endometrial cancer.

While hormone therapy does not cause cancer directly, specific types can increase the risk for certain hormone-sensitive cancers. For instance, combined estrogen-progestin therapy has been shown to increase breast cancer risk over time. The risk is dependent on the type of therapy, duration, and individual factors.

Yes, the risks can differ significantly. HT for menopausal symptoms primarily involves replacing lost hormones, while HT for cancer aims to block or reduce hormones that feed the tumor. This leads to different sets of risks and side effects, such as osteoporosis being a larger concern for certain cancer treatments.

A history of blood clots, stroke, or heart disease is often a contraindication for hormone therapy. Your healthcare provider will conduct a thorough risk assessment and may advise against HT or recommend alternative treatments based on your history.

No, the risks vary. For example, the method of delivery (oral versus transdermal) can affect the risk of blood clots, and using estrogen with progestin changes the cancer risk profile compared to estrogen-only therapy in women with an intact uterus.

Long-term use, especially in older individuals or when started well after menopause, is associated with a higher risk of serious health issues like cardiovascular disease, stroke, and certain cancers. The overall risk-benefit profile should be regularly reassessed with a doctor.

Yes, working closely with your doctor is key. This includes using the lowest effective dose for the shortest duration necessary, choosing the most appropriate delivery method, and maintaining a healthy lifestyle through diet and exercise. Regular check-ups are also vital.