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Hormone therapy: how these drugs work
Some cancers use hormones as fuel. Most breast cancers grow in response to estrogen, and prostate cancer grows in response to testosterone and other androgens. Hormone therapy (also called endocrine therapy) lowers those hormones or blocks them from reaching cancer cells. These drugs are often taken for years, as pills or regular shots, so side effects that seem mild at first, like hot flashes, joint aches, tiredness, low sex drive, and bone thinning, really matter for quality of life. Keep telling your team how you feel. There are many ways to ease these effects, and sometimes switching drugs helps.
ℹ️ General information to help you and your loved ones talk with your care team, not medical advice. Read our disclaimer.
On this page: Selective estrogen receptor modulators · Aromatase inhibitors · Estrogen receptor degraders · GnRH agonists (ADT shots) · GnRH antagonists · Androgen receptor inhibitors · Androgen synthesis inhibitors
Selective estrogen receptor modulators
Tamoxifen (tamoxifen) blocks estrogen's effect on breast cancer cells. It can be used before or after menopause, and in men. Hot flashes are common, and rare risks include blood clots and uterine cancer, so report unusual vaginal bleeding.
Aromatase inhibitors
Arimidex (anastrozole), Femara (letrozole), and Aromasin (exemestane) stop the body from making estrogen after menopause. Joint and muscle aches and bone thinning are the main side effects.
Estrogen receptor degraders
Faslodex (fulvestrant), given as two shots monthly, and Orserdu (elacestrant), a pill for ESR1-mutated cancer, break down the estrogen receptor itself in advanced breast cancer.
GnRH agonists (ADT shots)
Lupron (leuprolide) is androgen deprivation therapy (ADT). Shots every 1 to 6 months tell the testicles to stop making testosterone. Testosterone can briefly rise at first. Hot flashes, tiredness, and loss of sex drive are common.
GnRH antagonists
Orgovyx (relugolix) is a daily ADT pill that lowers testosterone quickly, without the first-week surge. Taking it every day matters.
Androgen receptor inhibitors
Xtandi (enzalutamide), Erleada (apalutamide), and Nubeqa (darolutamide) block testosterone from reaching cancer cells and are taken with ADT. Tiredness, falls, and fractures are watched, and Erleada can cause a rash.
Androgen synthesis inhibitors
Zytiga (abiraterone) stops androgen production everywhere in the body, including in the adrenal glands and the tumor itself. It's taken with prednisone, and liver tests, blood pressure, and potassium are checked.
Protecting your bones and heart
Lowering estrogen or testosterone over time can thin bones and affect heart health. Ask about a bone density scan, calcium and vitamin D, weight-bearing exercise, and checks of blood pressure, cholesterol, and blood sugar.
Side effect guides that may help
❓ Questions you and your loved ones can ask
- What is the goal of this treatment for me?
- How will we know if it's working?
- Which side effects should I call about right away, and what number do I call after hours?
- Which medicines, vitamins or supplements should I avoid?
- Will this affect my ability to work, drive, or care for my family?
- What will this cost me, and who can help me with coverage?
Written by the CSE Team from FDA labels and leading cancer centers. Not medical advice. · Last updated: October 15, 2026 · How we write
Sources
Last updated: October 15, 2026. We summarize these sources in our own words.