Estradiol

Key facts

• Estradiol is the principal human estrogen. As a tablet, patch, gel or spray it is used mainly for menopausal hormone therapy (HRT), replacing the estrogen the ovaries stop making at menopause.
• Patches and gels are applied to the skin once or twice weekly; tablets are usually taken once daily. Hot flush relief can start within weeks, and bone protection builds over months.
• If you still have a uterus, estradiol must be combined with a progestogen. Taken alone it thickens the uterine lining and raises the risk of endometrial cancer; estrogen therapy overall carries a small added risk of blood clots and stroke.
• Seek urgent care for one-sided weakness, sudden severe headache, chest pain, or a swollen, painful calf.

What estradiol treats

Estradiol treats moderate to severe menopausal symptoms: hot flushes, night sweats, vaginal dryness and the mood and sleep disturbance that come with the menopausal transition. It also prevents osteoporosis in women at high fracture risk who cannot take other bone medicines, and replaces estrogen in women who lose ovarian function early, from surgery, chemotherapy or premature ovarian insufficiency. It is not a treatment for general aging and is not a contraceptive.

How estradiol works

Estradiol binds estrogen receptors in the vagina, bone, brain and blood vessels, restoring signalling that falls away when the ovaries stop producing estrogen at menopause. This eases hot flushes and vaginal dryness and slows the bone loss that follows estrogen withdrawal. In the uterus, estrogen alone stimulates the lining to grow, which is why a progestogen is added in women who have not had a hysterectomy.

Before you take it

• Do not take estradiol if you have had breast cancer, a previous blood clot in the leg or lung, a stroke or heart attack, or unexplained vaginal bleeding.
• Tell your prescriber about migraine with aura, liver disease, or a strong family history of blood clots; these change the risk-benefit balance.
• Smoking combined with estrogen substantially increases clot and stroke risk.

Side effects

Common effects include breast tenderness, nausea, headache, bloating and irregular spotting, especially in the first months.

Stop and seek urgent medical care for any of these:

• Pain, swelling or warmth in one leg, or sudden breathlessness or chest pain.
• Sudden severe headache, vision changes, slurred speech or one-sided weakness.
• Heavy or unexpected vaginal bleeding after the first few months of treatment.

Safety essentials

• Never take estradiol without a progestogen if you still have a uterus: unopposed estrogen is a proven cause of endometrial cancer. Report any unscheduled bleeding to your prescriber promptly.
• Estradiol carries a small increased risk of blood clots and stroke, so your prescriber uses the lowest effective dose for the shortest time needed and reviews it periodically.
• Stop estradiol and seek care immediately for calf swelling, chest pain or stroke-like symptoms.
• Buy estradiol only from a licensed pharmacy.

This page is educational and does not replace advice from a doctor or pharmacist who knows your health history.