What is estrogen?
Estrogens are female sex hormones. The ovaries, adrenal glands, and adipose tissue in women synthesize estrogens from cholesterol. The testes in men also produce small amounts of estrogens.
There are three main forms of estrogen found in the body: Estrone (E1), estradiol (E2), and estriol (E3).
- Estradiol: The most potent and abundant estrogen in the body. It is responsible for most of the physiological estrogenic actions.
- Estrone: The second most abundant form of estrogen. It is mainly produced in the ovaries after menopause.
- Estriol: The estrogen with the weakest effect. The body produces it mainly during pregnancy.
Estrogen in women
In women, estrogen is responsible for the development of secondary sexual characteristics. It ensures, for example, that the breasts and pubic hair grow and the hips become wider.
Estrogen also regulates the menstrual cycle and is important for fertility.
Fluctuating estrogen levels during the cycle
Estrogen levels in the body fluctuate during the menstrual cycle in response to changes in hormone production in the ovaries.
The menstrual cycle is divided into three phases: the follicular phase (1st day of menstruation to ovulation), ovulation (day 12-14 in the cycle), and the luteal phase (after ovulation to end of cycle)
- Estrogen levels peak shortly before ovulation, around day 12-14 of the menstrual cycle.
- This peak in estrogen triggers the release of luteinizing hormone (LH), which in turn triggers ovulation.
- During the luteal phase, estrogen levels drop slightly but remain elevated.
How estrogen levels continue depends on whether the egg released into the fallopian tube at ovulation is fertilized:
- If the egg is fertilized, estrogen levels continue to rise to support early pregnancy.
- If the egg is not fertilized, estrogen levels eventually drop, triggering menstruation and the start of a new menstrual cycle.
Contraception with the Pill
Contraceptives of the estrogen-progesterone contraceptive type (also known as combined oral contraceptives, COCs) contain synthetic versions of estrogen and progesterone. They suppress the release of luteinizing hormone (LH) and follicle-stimulating hormone (FSH). As a result, they prevent ovulation.
In addition, estrogen-progesterone contraceptives thicken the cervical mucus (cervical mucus). This makes it harder for sperm to reach the egg to fertilize it.
Finally, hormonal contraceptives also affect the lining of the uterus in such a way that any egg that is fertilized is less likely to implant there.
Estrogen in men
In men, estrogen is synthesized mainly in the testes, in the Leydig cells. These are responsible for the production of testosterone, the primary male sex hormone. However, they also produce small amounts of estrogen, through the conversion of testosterone via the enzyme aromatase.
Fat tissue also produces small amounts of estrogen by converting testosterone via the same aromatase enzyme. This means that the higher the proportion of fat in a man’s body weight, the higher the resulting estrogen production.
However, too high estrogen levels in men have negative effects such as gynecomastia (enlargement of breast tissue) and infertility.
What are the normal values?
The normal range for estrogen levels depends on several factors, including age, gender, and whether pregnancy is present. It can also vary depending on the laboratory and testing method.
In addition, physicians always interpret the results of an estrogen determination in the context of the patient’s medical history and symptoms.
The following list contains common standard values (however, as mentioned, deviating standard values are possible depending on the laboratory):
|
Gender |
Age / cycle phase / pregnancy |
pg/ml |
|
m/f |
up to 10 years |
18-48 |
|
w |
until 15 years |
24-240 |
|
w |
120 years |
18-138 |
|
m |
up to 120 years |
18-48 |
|
w |
1st trimester |
155-3077 |
|
w |
409-6215 |
|
|
w |
without hormone replacement therapy |
31-100 |
|
w |
with hormone replacement therapy |
51-488 |
|
w |
with hormonal contraceptives |
48-342 |
|
w |
Follicular phase |
36-157 |
|
w |
Luteal phase |
47-198 |
|
w |
around ovulation |
58-256 |
|
Gender |
Age |
Estradiol value |
|
w |
0-2 months |
163-803 |
|
m |
0-2 months |
60-130 |
|
w |
3-12 months |
32-950 |
|
m |
3-12 months |
25-71 |
|
w |
1-3 years |
11-55 |
|
m |
1-3 years |
13-88 |
|
w |
4-6 years |
16-36,6 |
|
m |
4-6 years |
15-62 |
|
w |
7-9 years |
12-55,4 |
|
m |
7-9 years |
17-24,4 |
|
w |
10-12 years |
12-160 |
|
m |
10-12 years |
12-47 |
|
m |
13-15 years |
14-110 |
|
m |
16-20 years |
30-169 |
|
m |
> 21 years |
28-156 |
|
w |
~13-50 years |
by cycle phase |
|
w |
~51 years |
18,4-201 |
Normal values for free estriol (E3)
E1, E2 or E3 – When is which form of estrogen measured?
Estrone (E1) is mainly produced after menopause (= last menstrual period). Doctors measure it mainly to assess bone health and the risk of osteoporosis in post-menopausal women.
Measurement of estradiol (E2) is often performed in reproductive medicine and gynecology, for example in:
- an underactivity of the gonads (hypogonadism)
- cycle disorders
- sterility
- polycystic ovary syndrome (PCO)
- @ certain cancers
E2 levels are also routinely measured when medications are used to induce ovulation in a woman as part of fertility treatment.
When is estrogen too low?
Low estrogen levels often occur in women during perimenopause, i.e. the period before the last menstrual period (menopause).
However, low estrogen can also result from certain diseases or treatments, such as Turner syndrome, anorexia nervosa, chemotherapy, or radiation therapy.
Estrogen and menopause
During menopause, estrogen levels in the body decrease as a result of the natural aging process. The ovaries produce increasingly less estrogen. As a result, the menstrual cycle becomes irregular and eventually stops altogether. The last menstrual period (menopause) usually occurs between the ages of 45 and 55 (on average at 51).
Long-term changes in estrogen levels during menopause can also promote health problems such as osteoporosis (bone loss), heart disease and cognitive decline.
To mitigate the effects of menopause, many women opt for hormone replacement therapy (HRT). This involves regularly adding synthetic versions of estrogen and progesterone to the body to maintain hormone levels in the body.
For more information, see our article on estrogen deficiency!
When is estrogen elevated?
Several factors can cause estrogen dominance in women – that is, estrogen levels that are too high relative to progesterone levels.
In men, for example, elevated estrogen levels can be a sign of an underlying disease such as Klinefelter syndrome or certain types of cancer.
You can find more information in our text on estrogen dominance!
What to do if estrogen levels are altered?
If estrogen levels are altered, doctors first look for the cause. In some cases, altered estrogen levels indicate a disease such as hypothyroidism or ovarian dysfunction. If these conditions are treated, estrogen levels often normalize.
In some affected individuals, hormone replacement therapy (such as during menopause) or lifestyle changes are useful in normalizing estrogen levels.
