Difference Between Estriol and Estradiol

Estriol vs Estradiol
 

Estriol and estradiol are considered as two main types of estrogen hormone. Estrogen is a family of hormones which are mainly produced in the female body. In estrogen family, there are at least two dozen different estrogens, among which the most important three are estrone (E₁), estradiol (E₂), and estriol (E₃).  Each of these hormones has different properties and is produced in different quantities at different stages of life.

What is Estriol?

Estriol is a less active form of estrogen present in the body. It is secreted by the placenta during pregnancy. The receptors of estriol are mainly located in the vagina, skin and hair follicles. The effect of this hormone may be the reason for the skin and hair “glow” that can often be seen in women during pregnancy. It is also found that estriol has a very little effect on the organs like bones, heart, brain and other crucial sites where estradiol has a great effect. In the human body, estradiol and estrone are converted to estriol, and hence, estriol is considered as the most abundant circulating estrogen hormone in the body.

What is Estradiol?

Estradiol is the most active and powerful form among the other estrogens from puberty to menopause. It is secreted by ovaries, starting from the very first menstruation cycle and stopping at menopause. It involves over four hundred functions in the body. Some of them are; estradiol travels to breast during the childbearing years and assists the lactation, prepares the uterine lining, helps to keep the bones healthy, keeps the vaginal wall moist and elastic etc. The receptors of estradiol are located in almost all the organ in the body. During pregnancy, estradiol level increases rapidly and at the end of pregnancy it usually reaches up to about 20,000 (pg/ml). The presence of estradiol in excess amounts could be harmful; thus it is converted into estrone, and then into estriol.

What is the difference between Estriol and Estradiol?

• Estradiol has two oxygen-hydrogen groups attached while estriol has three such groups.

• Estradiol is much more active and powerful than estriol.

• Unlike the estradiol, estriol is the largest circulating estrogen hormone as estradiol and estrone convert to estriol.

• Estradiol has many functions, whereas estriol has few.

• Estriol is secreted largely by the placenta during the pregnancy, whereas estradiol is produced by ovaries.

• The receptors of estradiol are located in almost all the organs, whereas those of estriol are concentrated in very few places including the vagina, skin and hair follicles.