Oestradiol (E2)

Oestradiol (E2)

April 21, 2021


What is Oestradiol?

Oestrogen, also known as estrogen, is the female sex hormone that is responsible for the development and regulation of the female reproductive system and secondary sex characteristics.

There are three types of oestrogen hormones in our body: oestrone (E1), oestradiol (E2) and oestriol (E3). Among those, oestradiol is the most commonly measured because it is the most potent of the oestrogen hormones, and therefore has the greatest clinical importance.

Oestradiol is mainly produced in the ovaries in women and testicles in men under the stimulation of follicle stimulating hormone (FSH) and luteinising hormone (LH). Fat tissue also produces estradiol in both men and women. Excess fatty tissue can lead to higher oestradiol levels, especially when the fat is stored around the abdomen.

Why is this analysis important?

The female sex hormone oestrogen (including oestradiol), regulates the female menstrual cycle and also protects women from cardiovascular disease such as heart attacks and strokes. An oestradiol test is most commonly ordered by doctors to investigate the reason behind menstrual cycle abnormalities and to determine if a woman is preparing to enter menopause or has already been through menopause.

The drop in oestradiol levels in women after menopause makes them much more susceptible to both cardiovascular disease and osteoporosis (low bone density) as oestradiol is essential to bone health. Its predominant effect on bone is through suppressing bone resorption by its action on osteoclasts - cells that reabsorb bone.Taking medicine to replace the loss of oestrogen after menopause in females however, is not without risk, as it may increase the risk of breast cancer and blood clots. Therefore, any type of oestrogen replacement therapy should only be initiated after careful discussion with your doctor with individual risks discussed.

Although oestradiol levels are much lower in men than women, it is produced by both the testicles and fat tissue and plays an important role in male sexuality. Oestradiol levels naturally increase as a man ages at the same time as testosterone levels naturally decrease. In men, an oestradiol test is most commonly ordered by doctors to investigate conditions such as enlarged breast tissue (called gynecomastia) in men or if they have other symptoms suggestive of raised oestradiol such as erectile dysfunction.

In short, it is useful to analyse oestradiol levels in the blood to:

  • Investigate menstrual cycle abnormalities and infertility in women

  • Identify menopause or perimenopause in women

  • Investigate signs of feminisation such as enlarged breasts in men

  • Investigate possible reasons behind erectile dysfunction in men


The reference range for oestradiol levels in the blood can be different depending on the laboratory and technique used. Doctors usually also take into account a number of factors when evaluating oestradiol values.

High oestradiol levels in the blood may be associated with:

  • Test taken in mid-cycle phase of the menstrual cycle

  • Obesity

  • Certain liver diseases (such as cirrhosis)

  • Hyperthyroidism (overactive thyroid)

  • Intake testosterone supplements

  • Oestrogen producing tumors

  • Use of hormonal contraceptives

  • Oestrogen replacement therapy

Low oestradiol levels in the blood may be associated with:

  • Menopause

  • Dysfunction of the ovaries

  • Polycystic ovary syndrome (PCOS)

  • Extreme endurance exercise

  • Prolonged fasting

  • Use of hormonal contraceptives

  • Oestrogen replacement therapy

Other Considerations

Oestradiol levels fluctuate during the menstrual cycle. It is recommended for menstruating women to always take the test on day 3 in their menstrual cycle. For women who do not have menstrual cycles, and men, the test can be taken at any time.

Many hormonal contraceptives contain synthetic oestrogen which can interfere with the analysis. It is therefore not recommended to take the test if you are taking hormonal contraceptives.

Tests that include this marker




Related products

Related articles