The hormone estradiol is one of three main forms of estrogen—a prominent female sex hormone. Estradiol has a profound impact on reproductive health and regulating menstruation, and it also impacts other body systems such as the cardiovascular system (including the heart and blood vessels) and the musculoskeletal system (including your bones, ligaments, cartilage, and tendons). So abnormally high or abnormally low levels of estradiol can have many different health implications. 
An estradiol blood test—sometimes called an E2 test—can easily tell you what your levels of this hormone are; the challenging parts are understanding your results and getting insurance to cover the cost of the test. InsideTracker now tests estradiol levels for females as part of the Ultimate plan, and gives insights as to what your levels mean, how they may be impacting other areas of your health, and what to do about unoptimized levels.
While InsideTracker’s personal health analysis breaks down what your results mean, here is a summary of what you need to know about estradiol blood testing.
What is estradiol?
Estradiol is primarily produced by the ovaries, and it’s also secreted by the adrenal gland and fatty tissues. This hormone plays a key role in the development of female sex characteristics, (like breasts) and regulating the menstrual cycle and reproduction. Estradiol levels naturally fluctuate during premenopause and continue to fluctuate before a decline in perimenopause. Fat tissues still produce some estradiol throughout the postmenopausal years, however, levels remain consistently low during this time—especially compared to the perimenopausal years. And the extent to which estradiol declines is associated with increased severity of vasomotor symptoms commonly experienced during menopause like night sweats and hot flashes. 
In addition to its role in sexual and reproductive function, estradiol contributes to bone health, skin integrity, vascular function, and mental health. Optimal estradiol levels during postmenopausal years are associated with a reduced likelihood of age-related conditions like bone mineral density decline and poor cardiovascular health. 
Do men produce estradiol?
While estrogens are primarily known as a female sex hormone, all bodies produce and require estrogens for optimal function—including men. Estradiol is also the most prominent form of estrogen in males and is produced by the testes. However, this hormone circulates in the blood in much smaller quantities in people with testes. Normal estradiol levels in males are linked to healthy sexual function. 
*As of now, estradiol is only included in InsideTracker’s Ultimate Plan for those who select female when they activate their test. The sex-based insights at InsideTracker are informed by biological sex, and if you use Gender Affirming Hormone Therapy, select the biological sex option that aligns with your therapy. Check out this article to read more.
What is the reference range for an estradiol blood test?
Blood test results are displayed against a reference range. Results that fall outside of the reference range—say they’re too high or too low—should be addressed with your healthcare practitioner, as they may indicate a medical concern.
Estradiol’s reference range has a lot of variables. Normal ranges differ based on menopausal status, menstrual cycle phase at the time of test, hormonal contraceptive use, and menopausal hormone therapy (MHT) use. [2, 4]
|Normal reference range for estradiol
Pre- and peri menopause
|Natural cycle, follicular phase
|Natural cycle, mid-cycle
|Natural cycle, luteal phase
|Birth control use
|No menopause hormone therapy
|Menopause hormone therapy use
Estradiol throughout the female lifespan
Clearly, estradiol levels can shift a lot. And as the table above shows, normal ranges can be quite wide. But at each stage, estradiol levels can fall outside of that range, and at each life stage, the impact of those altered levels can have different impacts on the body.
Let’s dive into what estradiol levels mean for pre, peri-, and postmenopausal women.
Estradiol levels in premenopausal women
Estradiol levels fluctuate cyclically in premenopausal women and depend on the use of hormonal contraceptives (like the birth control pill, vaginal ring, et.). In women with a regular menstrual cycle, estradiol fluctuates readily. Levels are the lowest levels during the early follicular phase (menses), they peak during ovulation and then plateau during the luteal phase.
Hormonal contraceptive use stabilizes these peaks and dips of estradiol by blunting the increase of the hormone during the luteal phase of the menstrual cycle—therefore leading to more consistent estradiol levels throughout the menstrual cycle. 
What do low levels mean?
Premenopausal women with low estradiol levels may experience irregular or infrequent periods, difficulty sleeping, mood swings, and low libido. Low-calorie intake (chronic underfueling) can contribute to low estradiol levels. However, since the secretion of this hormone is regulated by the brain’s pituitary gland, low levels may also mean that something is impacting that communication pathway. 
What do high levels mean?
Symptoms of high estradiol levels include heavier and/or more frequent periods, worsening premenstrual syndrome (PMS) symptoms, fatigue, and low libido. The use of fertility treatments and estrogen-containing contraceptives may contribute to high estradiol levels. Having excess body fat, smoking cigarettes, and eating a diet high in saturated fat and added sugars can also contribute to elevated estradiol levels. Prolonged high estradiol levels have several medical implications for a woman later in life (which are best addressed through individualized care with a physician). 
Therefore, optimizing estradiol levels at each stage of life is essential for overall health.
Estradiol levels in perimenopausal women
The ovaries slowly stop producing estradiol as a woman nears the end of her reproductive years, leading to a natural decline in levels of this female sex hormone. During the perimenopausal years, estradiol levels are often in flux as menstrual cycles occur less regularly until the onset of menopause (when a woman hasn't experienced a menstrual cycle in 12 months). 
Hormonal contraceptive use can also stabilize estradiol fluctuations in perimenopausal women compared to those not using hormonal contraceptives. 
What do low levels mean?
Low estradiol levels during perimenopausal years can contribute to vasomotor symptoms like hot flashes and night sweats and other symptoms like stress and difficulty sleeping. Every woman experiences menopausal symptoms a bit differently. Generally, improving estradiol levels can improve the severity of menopausal symptoms you may be experiencing. 
Perimenopausal women with low estradiol levels are also at an increased risk for low bone mineral density and cardiovascular disease compared to those with optimal estradiol levels, making estradiol a hormone to optimize bone and heart health. [6, 7]
What do high levels mean?
Inconsistencies in estrogen levels during perimenopause mean that sometimes, estrogen levels surge and then plummet. These drastic shifts can lead to irregularities in the menstrual cycle (such as shorter or longer times between periods) Consistently high levels of estradiol can increase your risk for clinical conditions postmenopause. So, an optimal estradiol level during your perimenopausal years is critical for overall health as you age. 
Estradiol levels in postmenopausal women
During the postmenopausal years, a woman’s body stops converting a weaker form of estrogen—estrone—to estradiol, contributing to a decline and subsequent low levels of estradiol levels compared to premenopause. 
What do low levels mean?
Similar to perimenopause, low estradiol levels in your postmenopausal years can increase the frequency and severity of menopause-related symptoms like hot flashes, night sweats, anxiety, and trouble sleeping. Low estradiol levels can also negatively impact bone mineral density, increasing osteoporosis and cardiovascular disease risk. 
What do high levels mean?
Factors like elevated testosterone levels, excess body fat, stress, and alcohol intake may increase estradiol levels in postmenopausal women. While higher estradiol levels may protect postmenopausal women from symptoms like hot flashes and night sweats, having higher estradiol levels can lead to altered mood, increased frailty, and an increased risk for health conditions. The exogenous estrogens from Menopause Hormone Therapy (MHT) can also contribute to higher estradiol levels. Consult with your physician before modifying any use of MHT. [9, 10]
How does estradiol affect other blood biomarker levels?
Estradiol is delicately connected to many processes in the body. So, it’s no surprise that altered estradiol levels are linked—positively or negatively—to other blood biomarkers.
The chart below describes how biomarkers are correlated to estradiol and the mechanism behind it, given the current scientific literature.
|The impact of elevated estradiol on blood biomarker levels
|Decreased total and LDL cholesterol
|Elevated estradiol levels are associated with decreased total cholesterol and LDL cholesterol levels—and vice versa. Estradiol upregulates LDL receptors, which improves the body’s ability to clear LDL particles from the bloodstream. [11, 12]
|In premenopausal women, elevated estradiol levels are associated with reduced hsCRP levels (a marker of inflammation). Estradiol has an anti-inflammatory effect on cellular tissue by reducing inflammatory markers and the spread of inflammatory cells. [13, 14]
|Elevated estradiol levels are associated with increased hsCRP and CRP levels. This relationship may be explained by increases in adipose (fat) tissue in postmenopausal years, as adipose tissue secretes estradiol, promoting inflammation. This contrasts the association observed between estradiol and hsCRP in premenopausal women. 
|Increased testosterone and DHEAS
|Elevated estradiol levels are associated with increased testosterone and DHEAS, as they are precursors to estradiol.
Can you improve unoptimized estradiol levels?
Estradiol levels that fall outside the reference range should be addressed with a healthcare practitioner, who can account for your full medical history.
An InsideTracker analysis displays estradiol blood test results using the reference ranges provided but then takes the analysis a step further by creating optimal zones based on menopausal status (pre, peri-, or postmenopausal) and exogenous hormone use for females. For lab values that fall outside of a given optimal zone, a person may see recommendations for food, supplements, and/or physical activity that can positively impact estradiol levels.
How can you get your estradiol levels measured?
Knowing your estradiol levels can provide critical insight into your hormone health—and can help to determine your next course of action, whether that’s no change to your current routine, or speaking with your physician about your results.
But an estradiol blood test isn’t always included in standard bloodwork.
When you measure your estradiol with InsideTracker’s Ultimate Plan, you can track your levels over time, understand its impact on your other biomarkers, and receive recommendations aimed at improving this marker. Continuously reassessing estradiol levels is a critical component of health management, as high and low levels of estradiol are associated with notable symptoms and disease risks. 
As estradiol can have clinical implications, InsideTracker recommends monitoring estradiol and working with a healthcare provider for clinical support.
Since estradiol levels vary depending on where a person is during their menstrual cycle or whether they are on contraceptives, the ideal time to have your levels tested does change. Check out this guide on when InsideTracker recommends you get estradiol levels tested.
- Estradiol (E2) is the most potent and prevalent form of estrogen during a woman’s reproductive years
- Estradiol levels change a lot throughout a woman’s lifespan, and at each stage of life, too high or too low of levels can negatively impact health
- The optimal level of estradiol depends on your current life stage and whether or not you take hormone medications (such as hormonal contraceptives or menopause therapy)
- Estradiol levels are measured via a blood test either at the request of a physician or through services like InsideTracker