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Blood Test Tracker

Estradiol (E2)

The main estrogen in women of childbearing age. It rises and falls through the menstrual cycle and drops after menopause.

AI-verified against cited sources. Awaiting expert reviewAlso called E2LOINC 2243-4

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The usual range for Estradiol depends on sex. Choose female or male above to see where you stand.

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What it is

Estradiol (E2) is the most active form of estrogen. In women who have periods, the ovaries make most of it, and levels climb and fall across the menstrual cycle. After menopause the ovaries make very little, so levels drop. Men make small amounts too, mostly in the testes and from the body converting testosterone into estradiol. Body fat and the adrenal glands make some in both sexes.

Why it matters

Estradiol helps control the menstrual cycle and supports fertility, bone strength and other body systems in both sexes. It's often checked along with FSH and LH when periods are irregular or have stopped, when trying to conceive, during fertility treatment or hormone therapy, and when puberty seems early or late. In men, it can be part of looking into breast tissue growth. One result can be hard to read alone, because usual levels vary so much by sex, age and cycle day.

If it’s low

A low result is expected after menopause and early in the menstrual cycle. In younger women, a level that stays low can be linked to missed or stopped periods, low body weight, very heavy exercise, or a problem with the ovaries or the pituitary gland. Low estrogen can affect bone health over time, so a level that stays low is worth discussing with a clinician.

Common causes

  • Menopause or the years leading up to it (perimenopause)
  • The early part of the menstrual cycle, just after a period
  • Hormonal birth control, which quiets the ovaries
  • Low body weight, not eating enough, very heavy exercise or severe stress
  • A problem with the pituitary gland or the hypothalamus (the brain area that signals it)
  • Ovaries that slow down early (primary ovarian insufficiency), including after chemotherapy or radiation
  • Chromosome conditions such as Turner syndrome
  • Medicines that lower estrogen on purpose, such as aromatase inhibitors and GnRH analogues
  • In men, rare inherited conditions that block estrogen production

What can help

  • Ask your clinician whether FSH, LH and other hormones should be checked too
  • Ask whether your bone health needs a closer look if levels stay low for a long time
  • If you take a hormone treatment, ask how your result fits your treatment plan

If it’s high

A high result is often explained by timing or medicines. In women who have periods, levels peak just before ovulation, and they are very high in pregnancy and during fertility treatment. Estrogen medicines raise levels on purpose. A high result that these don't explain is worth discussing with a clinician, who can look at the full picture. In men, a higher level is most often linked to extra body fat, testosterone or steroid use, or liver disease, and less often to other causes a clinician can look into.

Common causes

  • The normal peak just before ovulation
  • Pregnancy
  • Fertility treatment that stimulates the ovaries
  • Estrogen medicines, including hormone therapy
  • Higher body fat, which makes more estrogen from other hormones
  • Liver disease, because the liver helps clear estrogen from the blood
  • Testosterone or anabolic steroid use, which the body partly converts to estradiol
  • Polycystic ovary syndrome (levels can be normal or high)
  • Rarely, a tumor of the ovary, testis or adrenal gland that makes estrogen
  • A false high from lab interference, such as fulvestrant treatment or high-dose biotin

What can help

  • Share your medicines, supplements and cycle day with your clinician so the result can be read in context
  • Ask whether the test should be repeated on a specific day of your cycle
  • Ask whether a different test method would suit you better

Usual ranges

What labs print as the reference range, by who was tested. Ranges differ a little between labs, so the range on your own report is the one your result is judged against.

The usual range depends on sex. Choose women or men to see the one that applies.

See Estradiol by age and sex, with the U.S. survey numbers where they exist.

If this applies to you

Estradiol means a little more for some people. Open the one that fits you.

Endurance athlete

In women, under-fuelling is linked to lower estrogen and to missed or stopped periods. Periods that stop are one of the main signs the IOC uses when it looks for REDs, once other causes have been ruled out.

Blood tests for endurance athletes

Trying to conceive

Estradiol is read together with early-cycle FSH. When periods have stopped, ASRM says the pair can tell ovarian insufficiency (high FSH with low estradiol) apart from missed periods caused by the brain's signals slowing down (low or normal FSH with low estradiol).

Blood tests for trying to conceive, including IVF

Perimenopause or menopause

NICE advises against using estradiol, AMH or inhibin tests to identify menopause at 45 or over. On hormone therapy, the FDA label for estradiol tablets says the dose is guided by how you respond rather than by estradiol or FSH levels.

Blood tests in perimenopause and menopause

On gender-affirming hormones

If you take estradiol, guidelines suggest checking it about every 3 months in the first year, then once or twice a year once your dose is steady. The aim is a level that matches your gender identity, though WPATH notes ideal targets haven't been settled. Conjugated estrogens can't be followed this way.

Blood tests on gender-affirming hormones

On testosterone therapy

Men need some estradiol too. The Endocrine Society notes it helps prevent gains in body fat and hot flashes. In the FDA label's studies of one testosterone gel, estradiol levels moved in step with testosterone.

Blood tests on testosterone therapy

How common is your level?

NHANES describes the US civilian, non-institutionalized population, not a 'healthy' reference group. People with disease, on medication, fasting or not (except fasting-subsample markers), smokers and so on are all included. A percentile says where a value sits among Americans of that sex and age, not whether it is normal.

How Estradiol varies with age in the U.S.Shaded: middle 90% and middle 50% of people. Line: the median. pg/mL. Point at any age, or focus the chart and use the arrow keys, to read both sexes in words.

Use the left and right arrow keys to read each age. Shift moves five years.

Reference data derived from CDC/NCHS National Health and Nutrition Examination Survey (NHANES), cycles 2015-2016, 2017-March 2020 (pre-pandemic), August 2021-August 2023. Analysis by bloodtesttracker.com; not endorsed by CDC, NCHS or HHS.

Explore Estradiol by age and sex: every percentile as a table, with a download.

What can affect your result

  • Menstrual cycle day: levels are lowest early in the cycle, peak just before ovulation, and rise again in the second half
  • Age and menopause status
  • Pregnancy: levels are far higher, so the usual adult ranges don't apply
  • Estrogen medicines, hormonal birth control and fertility drugs
  • Body fat, body weight and liver function
  • Test method: standard immunoassays can read too high at low levels, and LC-MS/MS is more accurate for men, children, postmenopausal women and people taking aromatase inhibitors
  • Different labs and methods give different numbers, so ranges aren't interchangeable
  • High-dose biotin supplements can interfere with some immunoassays. Labcorp advises stopping biotin at least 72 hours before the draw unless your clinician says otherwise.
  • Fulvestrant treatment can cause falsely high results on immunoassays. LC-MS/MS is not affected (Mayo, Labcorp).
  • Standard immunoassays can be inaccurate at low levels (men, children, postmenopausal women, people taking aromatase inhibitors). Sensitive LC-MS/MS is preferred there.
  • People treated with mouse monoclonal antibodies, or who had them for imaging, can get erroneous immunoassay results.
  • Serum left on gel separator tubes for more than about 72 hours can read low, because estradiol sticks to the gel (Quest).
  • Estrogen medicines, hormonal birth control and fertility drugs change estradiol on purpose, so tell the person reading the result what you take.
  • Results from different methods or labs shouldn't be compared directly. Use the same method for repeat tests when you can.

Any time of day for most purposes. If you still have periods, the day of your cycle matters more than the hour. Estradiol reflects what your ovaries and any estrogen medicine are doing right now. It can change within days, and it swings across a menstrual cycle.

When to talk to a clinician

Talk with a clinician if you've missed more than one period and you aren't pregnant, if you have any vaginal bleeding after menopause, or if you're a man with new breast growth or tenderness. For children, talk with a clinician if puberty starts before age 8 (girls) or 9 (boys), or hasn't started by age 13 (girls) or 14 (boys).

Questions you could ask

  • Which method did my lab use, and is it the right one for me?
  • How should I time my next blood draw in my cycle?
  • Do my medicines or supplements affect this result?
  • Could my cycle day, pregnancy or a medicine I take explain this result?
  • Should we repeat the test on a specific day of my cycle?
  • Would a different estradiol test method be better for me?

Questions people ask

Why does my estradiol range look so wide?

Estradiol changes a lot through the menstrual cycle. Labs print a separate range for each phase, and those ranges can overlap. Your result is easiest to read when you know which day of your cycle the blood was drawn.

What's the difference between a standard and a "sensitive" estradiol test?

Standard immunoassay tests work well for the higher levels seen in women who have periods. At low levels, such as in men, children, women after menopause or people taking aromatase inhibitors, they can be less accurate. Labcorp, Quest and ARUP point these groups to a sensitive mass spectrometry (LC-MS/MS) test. Results from different methods shouldn't be compared directly.

Can an estradiol test tell me if I'm in menopause?

Not on its own. Estradiol can swing widely during perimenopause, and the levels overlap with those in regular cycles. UK NICE guidance advises against using estradiol to identify menopause in people aged 45 or over, since your symptoms and period pattern are more useful. Clinicians may use FSH, along with the full picture, for people under 45.

How do I convert pg/mL to pmol/L?

Multiply pg/mL by 3.67 to get pmol/L, so 100 pg/mL is about 367 pmol/L. To go the other way, multiply pmol/L by 0.2724. Some labs print the same number as pg/mL in ng/L.

Why do men have estradiol?

In men, small amounts of estradiol are made mostly from testosterone. It plays a part in bone health and in sperm development. Men's levels are low, so a sensitive test is often preferred.

Show the science and sources

Units

  • 1 pg/mL = 1 pg/mL
  • 1 pg/mL = 3.671 pmol/L

Open the Estradiol unit converter

Is a change real?

Estradiol naturally varies about 14% from test to test in the same healthy person. Between two results from the same lab, a change of roughly 43% or more is unlikely to be day-to-day noise or lab variation (95% reference change value). Source: Sex Hormones and Adrenal Steroids: Biological Variation Estimated Using Direct and Indirect Methods (Roys EA et al.).

For clinicians and researchers

Estradiol (17β-estradiol) is the most potent circulating estrogen. It's made mainly by ovarian granulosa cells, with smaller amounts from the testes, the adrenal glands and peripheral aromatization of testosterone in fat tissue. After menopause, peripheral conversion of adrenal androstenedione to estrone becomes the main source, so estrone predominates. Immunoassays perform well at the concentrations of reproductive-age women but lose accuracy and specificity at low concentrations, where LC-MS/MS is preferred. The Endocrine Society position statement (Rosner et al., 2013) notes persisting method-to-method differences and standardization problems. Fulvestrant cross-reacts 1% to 5% in immunoassays and, at its peak dose, can cause dramatically false-high results, while LC-MS/MS is essentially unaffected. Intervals depend on the assay. For men, Labcorp's Roche ECLIA lists 7.6–42.6 pg/mL, Mayo's LC-MS/MS 10–40 and ARUP's LC-MS/MS 10–42. For postmenopausal women, Labcorp's immunoassay lists <6.0–54.7, ARUP's immunoassay <25.1, Mayo <10 and ARUP's LC-MS/MS 2.0–21.0. With the large within-cycle swing, interpret a single value with cycle day, age, medicines and method. NICE NG23 advises against using oestradiol to identify perimenopause or menopause in people aged 45 or over. Conversion: pg/mL × 3.671 = pmol/L (MW 272.4).

LOINC 2243-4 (primary), 14715-7, 35384-7, 72873-3. Specimen: serum-or-plasma.

Sources

  1. Estradiol (test 004515), Labcorp
  2. Estradiol, Sensitive, LC/MS (test 140244), Labcorp
  3. EEST - Estradiol, Serum, Mayo Clinic Laboratories
  4. Estradiol (Adult Premenopausal Females or Individuals on Estrogen Hormone Therapy) (test 0070045), ARUP Laboratories
  5. Estradiol (Adult Males, Children, Postmenopausal Females, or Individuals on Estrogen-Suppressing Hormone Therapy) (test 0093247), ARUP Laboratories
  6. Estradiol (test code 4021), Quest Diagnostics
  7. Challenges to the Measurement of Estradiol: An Endocrine Society Position Statement, Journal of Clinical Endocrinology & Metabolism (2013)
  8. Menopause: identification and management (NG23), National Institute for Health and Care Excellence (NICE)
  9. Estrogen Levels Test, MedlinePlus (NIH)
  10. Estradiol (PubChem CID 5757), PubChem (NIH)

AI-verified against cited sources. Awaiting expert review. Last reviewed 2026-10-03. How we build and check these pages.

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