Estradiol is a medication that may be used either topically or orally for a number of different conditions. It contains estrogens similar to those produced in people’s bodies, in larger part by women than men. People may use topical or oral forms to treat some symptoms associated with loss of estrogens through menopause, which include things like hot flashes, or inflammation of the vagina that can result in pain during intercourse. It can also be used to treat dry or itching vaginal conditions, to relieve some symptoms of breast cancer or as hormonal replacement when ovaries stop working or are removed. A less common use is during end stage prostate cancer in men.

There are many estradiol side effects. Many of these here listed affect at least 5% of the people who take this medication in various forms. For instance headache is one of the most common estradiol side effects and may affect up to 20 % of people who take it.

Numerous other estradiol side effects exist. These include dizziness, breast pain, increased risk for yeast infections, redness or irritation when the medication is used topically, and flu-like symptoms or arthritic pain. Hair loss is not infrequent and people have also reported stomach upset, particularly nausea or vomiting, and incidences of spotting in between periods or other menstrual irregularities.

Most of the guidelines for use of this medication suggest it be used for shortest possible time periods. There are some potentially dangerous estradiol side effects that require vigilance. There is an increased risk of heart attack, stroke, deep vein thrombosis, and blood clots in women who take this medication, especially if they smoke and are over the age of 35, or simply if they are over the age of 50. The trend toward using medications as hormone replacement therapy (HRT) has declined in the 2000s because of these increases in serious illness and chance for elevating cancer risk, especially breast and uterine cancer.

Certain populations should note a few other estradiol side effects. People who have diabetes and take this medication should monitor blood sugar levels carefully, as these may change. Those who have thyroid disorder may need to watch thyroid levels carefully. Even in people without hypothyroidism, long-term use of estradiol may reduce thyroid hormone levels to below normal readings.

There is also some concern about the potential for estradiol to cause dementia. This has been noted in some older patients who use it. In general, women who are well over menopause are discouraged from using this medication, especially on a long-term basis.