Home Hormones Estradiol vs Estrogen – What is the Difference between these Definitions?

Estradiol vs Estrogen – What is the Difference between these Definitions?

Posted by admin in Hormones Category. Reviewed and Updated: 3 February, 2018

Many people often mistakenly believe that, estrogen and estradiol mean the same. The word “estrogen” is often used in the singular. In fact, the difference between them is that estrogens are a group of steroids, the main of which are: estriol, estradiol and estrone. The thing which unites them is their common chemical structure. Estradiol is the most potent hormone of the three; maybe therefore it is often called estrogen.

Some historical & scientific facts

In 1923, the American scientist E. Doisy together with E. Allen first identified follicular hormones, and, three years later, he received one of them in a crystalline form. This was the beginning of the discovery and study of one of the most important groups of sex hormones, estrogens.

Their name derives from the Greek word, which in transcription sounds like “oistros”, and in translation means inspiration. The suffix “-gen” at the end gives it an additional meaning – generating, causing.

These hormones exist not only in the human body; they are synthesized in all vertebrates and in some species of insects. Even plants, for example, sage or stevia, contain substances similar in structure and action to estrogens. These substances are called phytoestrogens. Due to their structure, similar to estradiol, these natural non-steroid plant compounds can cause an estrogenic and (or) anti-estrogenic effect. At the moment, studies of the effect of phytoestrogens on the human body continue. A typical example of the hormonal effect of phytoestrogens in mammals is the so-called “clover disease” found in sheep and other pastoral animals. Farmers have noticed that sheep, who ate mainly Trifolium subterraneum type of the plant, often experience infertility & other reproductive problems. The reason for this is isoflavone substances, which provide a hormone-like action in the organism of sheep.

Main features of estradiol

Estradiol without exaggeration can be called the main estrogen in the female body (however in the male body it is also present). It is produced mainly by the ovaries and in very small quantity by the adrenal glands.

Its level varies in different phases of the cycle. At the beginning of it estradiol features low levels, but before ovulation, its amount increases threefold, and on the last day of the cycle, if pregnancy does not occur, it decreases again.

According to the research, it is estradiol that is responsible for many processes occurring in the female body. There are a lot of them, but the main ones are as follows:

  • Controlling blood cholesterol levels and ensuring blood coagulation.
  • Providing bone tissue density.
  • Regulating the cardiovascular and nervous system.
  • Maintaining a stable water-salt balance.
  • Influencing the intimate sphere of a woman’s life and the proper functioning of the genitals.
  • Promoting muscle growth (in fact, estrogen is the main hormone responsible for the growth of muscle mass in women instead of testosterone, therefore if a woman takes steroids such as testosterone cypionate, she develops masculinization, that is, masculine traits);
  • Providing favorable conditions for the maturation of the follicle, fertilization, fixation and proper development of the embryo.

In general, estradiol is responsible for more than 400 functions for a woman. In post menopause, when the follicles are no longer available, there is no organ to develop estradiol and its source is lost. After this, various post-menopausal skin lesions, osteoporosis, muscle atrophy and their replacement with fat, and other negative effects appear. To minimize the effects of menopause, various estrogen pills, estrogen creams, etc. are prescribed.

Estradiol vs estrogen – the difference

So, it is wrong to consider estrogen and estradiol the same hormone. These concepts are not even synonymous. After all, estrogens are not a single hormone or even three basic ones, the functions of which are the most important. To date, about 30 types are known.

Perhaps, they share only one feature: with a lack of any of these hormones the health of a woman and the normal course of pregnancy will be in question. Therefore, the term “estrogens” is more correctly used to denote the whole group.

However, in most cases, estrogen test involves the determination of estradiol alone. The only exception is the so-called triple test, also called triple screen, conducted in the early pregnancy phase. With the help of this test free estriol is determined, which is one of the main markers of the condition of a woman and her future baby.

The triple test is a screening test usually performed between 15 and 20 weeks of pregnancy. It includes not only the determination of estriol, but also that of HCG and blood alpha-fetoprotein. In some countries like France, this test is proposed to all pregnant women under the age of 38. This test can help identify at-risk pregnancies, those with an increased risk of delivering a baby with certain problems including:

  • Down syndrome (DS or DNS), also known as trisomy 21;
  • aneuploidies, including other trisomies, and polyploidies;
  • spina bifida;
  • anencephaly;
  • a deficiency of the abdominal wall.

This information can help women and their doctors in deciding whether to do diagnostic tests such as amniocentesis or choriocentesis. Genetic counseling is usually indicated if this test is positive.

The bottom line on estradiol vs estrogen

Is estradiol same as estrogen? Estrogen and estradiol do not mean the same thing. In fact, estradiol is an estrogen or hormone of estrogen group. This female sex hormone is the most active in its group.

Low estrogen levels (as well as low progesterone levels) lead to a deterioration of a female health condition. Therefore, it is very important to consult a qualified doctor and take a blood test if you experience symptoms of low estradiol levels.