Home Medicines Estradiol: effect, areas of application, side effects

Estradiol: effect, areas of application, side effects

by Josephine Andrews
Published: Last Updated on 315 views

Estradiol is an endogenous hormone and is also one of the most important active ingredients in contraception and hormone treatment during and after menopause. Estradiol and two other very similar hormones found in the female body are colloquially referred to as “estrogen”. Here you can read more about the effects and use of estradiol, side effects and other interesting facts.

This is how estradiol works

The hormone estradiol (also called 17-beta-estradiol) is formed naturally in the human body. In women, the largest amount is produced in the ovaries. In men, who have much lower levels of estradiol in the body, it is made in the adrenal cortex and testicles .

The term ” estrogen ” includes the hormones estradiol, estrone and estriol.

Estradiol (estradiol) is the most effective of all three hormones, which is why it is also used as a medicinal substance (in the form of estradiol hemihydrate, which still contains some water due to production). In the child-bearing age (from the first menstrual period to the menopause), it is also the most common estrogen in the woman’s body. Estriol takes over this role during pregnancy and estrone after menopause.

Estrogens are not only very important for the formation of female sexual characteristics (such as ovaries, uterus , vagina and breasts), but also for their function.

Menstrual cycle & hormone fluctuations

The approximately 28-day menstrual cycle is largely dependent on the changing hormone levels in the woman’s blood :

In the first half of the cycle ( follicular phase ), the pituitary gland ( pituitary gland ) releases the hormone FSH (follicle-stimulating hormone), which stimulates the maturing of egg sacs (follicles) in the ovaries.

These produce estrogens. On the one hand, this causes the uterine lining to grow (in preparation for the possible implantation of a fertilized egg cell). On the other hand, the rising estrogen level in the blood leads to the release of LH (luteinizing hormone) from the pituitary gland. This hormone triggers ovulation  the most mature follicle ruptures on the surface of the ovary and releases a mature egg into the fallopian tube , where it remains fertile for about 24 hours.

The luteal phase follows ovulation : the blood levels of estrogen, LH and FSH now drop, while the concentration of the luteal hormone ( progesterone ) increases. The corpus luteum develops from the follicle left in the ovary after ovulation . The corpus luteum hormone it produces further prepares the lining of the uterus for the eventual implantation of the fertilized egg cell.

If fertilization does not take place, the corpus luteum recedes so that no further progesterone is produced. As a result, the thickened uterine mucosa recedes and menstrual bleeding begins, during which the mucous membrane is excreted together with blood. The menstrual period is the beginning of a new menstrual cycle.

Estradiol for contraception

Taking estradiol (as a ” pill “) suppresses the release of FSH – ovulation no longer occurs, which means that fertilization and subsequent pregnancy are not possible.

In adaptation to natural hormone fluctuations, the “pill” is only taken for 21 days. Then you stop for seven days or just take one inactive tablet.

Estradiol for hormone replacement therapy in menopause

After the menopause, i.e. after the monthly menstrual period has stopped in middle age, the estradiol level in the body drops. Since the hormone not only affects the female organs, but also affects the psyche, general performance and bone density, the hormone drop during or after menopause can lead to various complaints .

These include mood swings , exhaustion, hot flashes , vaginal dryness and bone loss. These symptoms can often be alleviated, if not eliminated entirely, with estradiol therapy.

In the past, women were given very large doses of hormones, which in some cases led to side effects such as breast and ovarian cancer . In the meantime, lower-dose and therefore safer hormone preparations are in use.

intake, degradation and excretion

After being taken as a tablet, estradiol is absorbed into the blood through the intestines . The absorption rate is very low – it is only about five percent.

The highest drug level in the blood is reached after about four to six hours. In the liver , the estradiol is then converted into estrone, which is about ten times weaker. It is then excreted mainly via the kidneys (i.e. with the urine).

Do not confuse with 17-alpha-estradiol!

The active ingredient 17-alpha-estradiol (also called alfatradiol), which has the same structure but a different three-dimensional shape, has no effect as a female hormone, in contrast to the well-known 17-beta-estradiol.

However, it is used locally on the scalp for hair loss caused by excessive levels of DHT (dihydrotestosterone, a compound related to testosterone ). Here it inhibits the production of DHT and thus its negative effect on hair growth.

When is estradiol used?

Estradiol is mainly used for hormone replacement therapy (HRT) in the case of estrogen deficiency or menopausal symptoms (e.g. hot flashes, vaginal dryness).

The related active ingredient ethinylestradiol is used much more frequently for contraception, as it has an even more targeted effect and can therefore also be taken in smaller amounts of active ingredient. Combined tablets made from an estrogen (ethinyl estradiol or estradiol) and a progestin (e.g. norethisterone or drospirenone) are very often used for contraception, as this makes contraceptive protection even more reliable.

In addition to contraception, some of these preparations are approved for the treatment of moderate to severe acne and/or hirsutism in women of childbearing potential.

In addition to tablets, other dosage forms of estradiol are commercially available: transdermal patches for sticking to the skin , vaginal rings, solutions and sprays for application to the skin, and gels for topical application.

This is how estradiol is used

As a contraceptive (contraceptive), estradiol is taken, for example, in the form of tablets once a day, always at about the same time of the day. After 21 days, there is a seven-day break (there are also monthly packs with 28 tablets, in which case the last seven tablets contain no active ingredient).

In hormone replacement therapy, the doctor decides whether estradiol should be used continuously or in cycles. In the latter case, there is also a therapy-free week after three weeks of treatment. Other dosage forms of estradiol for hormone replacement therapy are estradiol gel and estradiol patches. The patches usually release the hormone evenly through the skin into the body over a few days. It therefore only needs to be changed every three to four days.

It is used in both areas of application (contraception, hormone replacement therapy) for as long as the effect is desired.

What are the side effects of estradiol?

Estradiol side effects, affecting one in ten to a hundred people treated, include headache , depression, abdominal pain , nausea, leg cramps, weight gain , tender chest , or chest pain . If chest pain occurs, you should inform the doctor – he or she may reduce the dosage.

What should be considered when using estradiol?


Estradiol must not be used in:

  • current or previous breast cancer
  • Existing or previous estrogen-dependent tumor (e.g. endometrial carcinoma = uterine cancer )
  • unexplained bleeding in the vaginal area
  • Previous or existing thrombosis (e.g. venous thrombosis)
  • genetic or acquired tendency to form thrombosis (blood clots)
  • recent arterial thromboembolic disease (e.g. myocardial infarction )
  • severe liver dysfunction or liver disease
  • Porphyria (group of metabolic diseases with disturbances in the structure of the red blood pigment hemoglobin )


The combined use of active ingredients that are broken down in the body by the same enzymes (cytochrome P450 in the liver) as estradiol can accelerate its breakdown and thus weaken its effect.

These include, for example, drugs against convulsions and epilepsy (phenobarbital, phenytoin , carbamazepine ), the tuberculosis drug rifampicin , certain drugs against HIV (nevirapine, efavirenz) and the herbal antidepressant St. John’s wort.

Long-term therapy or high doses of estradiol may increase the risk of breast and uterine cancer. This risk can be minimized by the lowest possible dosage and possibly by the additional administration of progestins.

The use of estradiol can also increase the risk of blood clots forming, which may then block a vessel (as in a pulmonary embolism ). This is especially true if a woman smokes or has other risk factors (high cholesterol , overweight , etc.).

age restriction

Hormone replacement therapies are used in women with reduced hormone production after menopause. This is usually in the late 40’s to 50’s.

There is practically no minimum age for the prescription of estradiol-containing pills. The initial prescription is based on the biological and psychological maturity, which the gynecologist checks in conversation with the patient.

pregnancy and breast feeding period

The active ingredient estradiol should only be used in girls and women from the onset of menstrual bleeding, but not in pregnant or breastfeeding women. If pregnancy occurs during treatment, treatment must be stopped immediately and a doctor contacted.

How to get medication with estradiol

The active ingredient estradiol requires a prescription in Germany, Austria and Switzerland in any dosage and is therefore only available in pharmacies with a doctor’s prescription.

Since when is estradiol known?

Steroid hormones, which include estrogens such as estradiol, but also testosterone and cortisone, were recognized very early on as important functional units in the body. The first estrogens were isolated and their structure elucidated by the chemist Adolf Butenandt as early as 1929. For this he received the Nobel Prize in Chemistry in 1939 together with the steroid researcher Leopold Ruzicka.

In 1930, an oral estrogen therapy was introduced for the first time. At that time it was still extracted from the urine of pregnant women.

Worthwhile chemical manufacturing processes for the active ingredient estradiol were only developed in the second half of the 20th century.

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