Letrozole — what it is and why people use it

Letrozole is a small oral pill that lowers estrogen. Doctors prescribe it most often for postmenopausal women with certain types of breast cancer, and fertility specialists use it off-label to help people ovulate. It’s not a hormone replacement — it blocks the enzyme aromatase, which makes estrogen in the body.

How letrozole works and common uses

For breast cancer, letrozole reduces estrogen that can fuel hormone-sensitive tumors. Typical cancer dosing is 2.5 mg once a day for years, depending on your oncologist’s plan. For fertility, clinicians usually give short courses early in the cycle (commonly 2.5–7.5 mg daily for 5 days) to stimulate ovulation. Many people prefer letrozole over clomiphene because it often causes fewer thin-lining issues and fewer multiple pregnancies.

Letrozole is intended for postmenopausal women when used for cancer. For fertility, it’s given to people who still have ovarian function. It should never be taken during pregnancy — it can harm a developing fetus — and reliable contraception is essential if there’s any chance of pregnancy while taking it for cancer.

Side effects, safety checks, and practical tips

Common side effects are joint and muscle pain, hot flashes, fatigue, nausea, and hair thinning. Because reducing estrogen can weaken bones, doctors often check bone density before starting letrozole and during long-term use. Tell your provider about any history of osteoporosis, heart disease, or severe liver problems.

Watch for red flags: new chest pain, sudden shortness of breath, severe leg swelling, sudden severe bone pain, or major mood changes. These need prompt medical attention. Also mention all other medicines and supplements you take — some drugs can affect liver metabolism and change how letrozole works.

Practical tips that help most people: take it at the same time each day (with or without food), keep scheduled bone-density or blood tests, and report persistent joint pain or mood shifts. If you’re using letrozole for fertility, your clinic will monitor ovulation with ultrasounds and blood tests to time insemination or intercourse safely.

Deciding whether letrozole is right for you depends on your diagnosis, menopausal status, bone health, and other medicines. Ask your oncologist or fertility specialist to explain the expected benefits for your situation and what monitoring they recommend. A simple conversation with your provider will clarify dosing, side-effect management, and safety steps so you can use letrozole wisely.