Estriol is the weakest of the three major naturally-occurring estrogens in women.

Estriol is a product of the metabolism of estrone and estradiol. Because of its weak estrogenic activity, estriol is sometimes preferred for intravaginal use as an alternative to systemic estrogen therapy for the treatment of urogenital atrophy in postmenopausal women.

It is also used in anti-aging skin creams as a form of topical estrogen replacement to counteract the effects of age-related estrogen loss on skin. Estriol is the major estrogen found in the maternal circulation during pregnancy; 90% of this circulating estriol is the product of metabolism of DHEA from the fetal adrenals, and so maternal estriol levels are used as an indicator of fetal health.

In non-pregnant women, estriol levels are similar in both pre- and post-menopause and are also similar to levels in men. Salivary estriol has been found to be predictive of increased risk of preterm labor in pregnant women. In nonpregnant women, it is most commonly used for monitoring of levels in women using estriol-containing supplements as part of hormone replacement therapy.

Estriol is one of three estrogen hormones. Estriol levels rise throughout pregnancy, helping to keep your uterus and unborn baby healthy. The levels are at their highest right before childbirth. They help prepare your body for labor and delivery.

Everyone makes estriol. But in people who aren’t pregnant, the levels are almost undetectable. Other names for estriol include oestriol and E3.

During pregnancy, estriol:

- Helps your uterus grow as the fetus gets bigger.
- Makes your body more sensitive to other pregnancy hormones.
- Prepares your body for labor and delivery and breastfeeding.

Patients with an EQ>1 have a higher survival rate after breast cancer, and may be at decreased risk for developing breast cancer. EQ often declines as women enter menopause.

The estrobolome is a network of over 60 genera of bacteria that can recycle or deconjugate inactivated estrogens for reabsorption into circulation by producing very powerful enzymes. This recycling process is handled by gut bacteria with beta-glucuronidase and beta-glucosidase activity. When the estrobolome is too abundant, the body is unable to efficiently eliminate estrogen, causing estrogens to build up and ultimately leading to estrogen dominance. On the other hand, if estrogen recycling (estrobolome) is too low, then this may lead to insufficient levels of estrogen in circulation.

Total estrogen is a reliable test for estrogen status and is used to detect hormone imbalances.

Estrogen is known as the “female” hormone. The four major naturally occurring estrogens in women are estrone (E1), estradiol (E2), estriol (E3), and estetrol (E4).

Normal Ranges for Total Estrogen in pg/mL:

Critical Range: anything outside the limits mentioned above.

Estrogen is known as the “female” hormone. The four major naturally occurring estrogens in women are estrone (E1), estradiol (E2), estriol (E3), and estetrol (E4).

Although estrogen is identified with females, it is also found in men.

Estrone (E1) is a significant estrogenic marker providing crucial insights into a woman's estrogen metabolism and overall hormonal balance. Estrone, primarily a product of peripheral aromatization of androstenedione, is one of the three major naturally occurring estrogens, alongside estradiol (E2) and estriol (E3).

In premenopausal women, estrone levels typically fluctuate with the menstrual cycle, whereas in postmenopausal women, it becomes the predominant form of estrogen, primarily produced in adipose tissue.

Produced by the ovaries, the estrone hormone is one of three types of estrogen, and it is one of the major hormones found in the bodies of postmenopausal women. While research into estrone function is still ongoing, since it is the least powerful of the three estrogen types, women should still understand this hormone and its known effects on the body.

- Weaker compared to Estradiol (Research says the estrogenic activity is about 4% of estradiol’s activity)

- Most abundant in menopause

- Made via aromatization in several tissues like fat and muscle

- Converts into estradiol (E2)

Estrone (E1) is also made by the ovary but in fat tissue in lesser quantities. While not as abundant in circulation as estradiol, estrone excess can still increase the risk for estrogen dominant cancers and estrogen dominant symptoms such as breast tenderness, heavy menstrual cycles, headaches, and erectile dysfunction and breast development in men just like estradiol. Estrone is commonly thought to be more abundant during menopause. 

Estradiol and estrone can interconvert into each other. 

Produced by the ovaries, the estrone hormone is one of three types of estrogen, and it is one of the major hormones found in the bodies of postmenopausal women. While research into estrone function is still ongoing, largely due to the fact that it is the least powerful of the three types of estrogen, women should still understand this hormone and its known effects on the body.

- Weaker compared to Estradiol (Research says the estrogenic activity is about 4% of estradiol’s activity)

- Most abundant in menopause

- Made via aromatization in several tissues like fat and muscle

- Converts into estradiol (E2)

Estrone (E1) is also made by the ovary but in fat tissue in lesser quantities. While not as abundant in circulation as estradiol, estrone excess can still increase the risk for estrogen dominant cancers as well as estrogen dominant symptoms such as breast tenderness, heavy menstrual cycles, headaches, and erectile dysfunction and breast development in men just like estradiol. Estrone is commonly thought to be more abundant during menopause. 

Estradiol and estrone can interconvert into each other. 

Produced by the ovaries, the estrone hormone is one of three types of estrogen, and it is one of the major hormones found in the bodies of postmenopausal women. While research into estrone function is still ongoing, since it is the least powerful of the three estrogen types, women should still understand this hormone and its known effects on the body.

- Weaker compared to Estradiol (Research says the estrogenic activity is about 4% of estradiol’s activity)

- Most abundant in menopause

- Made via aromatization in several tissues like fat and muscle

- Converts into estradiol (E2)

Estrone (E1) is also made by the ovary but in fat tissue in lesser quantities. While not as abundant in circulation as estradiol, estrone excess can still increase the risk for estrogen dominant cancers and estrogen dominant symptoms such as breast tenderness, heavy menstrual cycles, headaches, and erectile dysfunction and breast development in men just like estradiol. Estrone is commonly thought to be more abundant during menopause. 

Estradiol and estrone can interconvert into each other. 

Produced by the ovaries, the estrone hormone is one of three types of estrogen, and it is one of the major hormones found in the bodies of postmenopausal women. While research into estrone function is still ongoing, largely due to the fact that it is the least powerful of the three types of estrogen, women should still understand this hormone and its known effects on the body.

- Weaker compared to Estradiol (Research says the estrogenic activity is about 4% of estradiol’s activity)

- Most abundant in menopause

- Made via aromatization in several tissues like fat and muscle

- Converts into estradiol (E2)

Estrone (E1) is also made by the ovary but in fat tissue in lesser quantities. While not as abundant in circulation as estradiol, estrone excess can still increase the risk for estrogen dominant cancers as well as estrogen dominant symptoms such as breast tenderness, heavy menstrual cycles, headaches, and erectile dysfunction and breast development in men just like estradiol. Estrone is commonly thought to be more abundant during menopause. 

Estradiol and estrone can interconvert into each other. 

Produced by the ovaries, the estrone hormone is one of three types of estrogen, and it is one of the major hormones found in the bodies of postmenopausal women. While research into estrone function is still ongoing, since it is the least powerful of the three estrogen types, women should still understand this hormone and its known effects on the body.

- Weaker compared to Estradiol (Research says the estrogenic activity is about 4% of estradiol’s activity)

- Most abundant in menopause

- Made via aromatization in several tissues like fat and muscle

- Converts into estradiol (E2)

Estrone (E1) is also made by the ovary but in fat tissue in lesser quantities. While not as abundant in circulation as estradiol, estrone excess can still increase the risk for estrogen dominant cancers and estrogen dominant symptoms such as breast tenderness, heavy menstrual cycles, headaches, and erectile dysfunction and breast development in men just like estradiol. Estrone is commonly thought to be more abundant during menopause. 

Estradiol and estrone can interconvert into each other. 

Estrone is the predominant estrogen in post-menopausal women and inter-converts with estradiol. This conversion is dependant on the bidirectional activity of 17-beta-hydroxysteroid dehydrogenase, which also converts testosterone to androstenedione (an intermediate of androsterone, etiocholanolone, and estrone).

Estrone (E1), a key estrogen hormone, is a crucial marker in the Comprehensive 24-Hour Urine Steroid Hormone Profile Test, emphasizing its importance in assessing male hormonal balance and health. In men, while estrogen is typically associated with female physiology, estrone plays a significant yet often underestimated role. It is involved in bone metabolism, brain function, and cardiovascular health. Estrone is produced primarily from the conversion of androstenedione, a steroid hormone. The measurement of estrone levels in a 24-hour urine sample provides a comprehensive overview of its daily production and metabolism, offering valuable insights into the endocrine system's functioning.

Estrone is the predominant estrogen in post-menopausal women and inter-converts with estradiol. This conversion is dependant on the bidirectional activity of 17-beta-hydroxysteroid dehydrogenase, which also converts testosterone to androstenedione (an intermediate of androsterone, etiocholanolone, and estrone).

Produced by the ovaries, the estrone hormone is one of three types of estrogen, and it is one of the major hormones found in the bodies of postmenopausal women. While research into estrone function is still ongoing, largely due to the fact that it is the least powerful of the three types of estrogen, women should still understand this hormone and its known effects on the body.

- Weaker compared to Estradiol (Research says the estrogenic activity is about 4% of estradiol’s activity)

- Most abundant in menopause

- Made via aromatization in several tissues like fat and muscle

- Converts into estradiol (E2)

Estrone (E1) is also made by the ovary but in fat tissue in lesser quantities. While not as abundant in circulation as estradiol, estrone excess can still increase the risk for estrogen dominant cancers as well as estrogen dominant symptoms such as breast tenderness, heavy menstrual cycles, headaches, and erectile dysfunction and breast development in men just like estradiol. Estrone is commonly thought to be more abundant during menopause. 

Estradiol and estrone can interconvert into each other. 

Produced by the ovaries, the estrone hormone is one of three types of estrogen, and it is one of the major hormones found in the bodies of postmenopausal women. While research into estrone function is still ongoing, since it is the least powerful of the three estrogen types, women should still understand this hormone and its known effects on the body.

- Weaker compared to Estradiol (Research says the estrogenic activity is about 4% of estradiol’s activity)

- Most abundant in menopause

- Made via aromatization in several tissues like fat and muscle

- Converts into estradiol (E2)

Estrone (E1) is also made by the ovary but in fat tissue in lesser quantities. While not as abundant in circulation as estradiol, estrone excess can still increase the risk for estrogen dominant cancers and estrogen dominant symptoms such as breast tenderness, heavy menstrual cycles, headaches, and erectile dysfunction and breast development in men just like estradiol. Estrone is commonly thought to be more abundant during menopause. 

Estradiol and estrone can interconvert into each other. 

A component of the estrone level may be due to aromatization of androstenedione and testosterone by CYP19 (aromatase) enzyme in adipose tissue, and/or conversion from estradiol due to HSD17B activity. Aromatase up-regulation and increased intracellular estrogens in men may contribute to increased adiposity, metabolic syndrome, and prostate pathology. CYP19 enzyme is induced during times of stress, exposure to xeno-estrogens, high glycemic diet, excessive adipose tissue, and alcohol consumption.

Estrone is one of three main circulating estrogens in humans. Like estradiol, estrone is secreted by the ovaries, but it is also predominantly produced in peripheral tissues by the action of aromatase on its precursor androstenedione. Its estrogenic activity is intermediate to that of estriol, the weakest estrogen, and estradiol, the strongest. Estrone is converted to the more potent estradiol in tissues by the action of 17β-hydroxysteroid dehydrogenase, and through this conversion it represents the main source of circulating estradiol in postmenopausal women and in men.

Estrone is the predominant circulating estrogen in postmenopausal women, compared to estradiol which predominates in premenopausal women. This is because ovarian estradiol production declines significantly post-menopause while estrone production from androstenedione changes minimally compared to premenopause. The aromatization of androstenedione to estrone increases with increased body weight, since aromatase is prevalent in fat tissue. This increased availability of estrone contributes to the rise in circulating estradiol with increasing body mass index in obese postmenopausal women.