Biomarker guide
Estradiol (pg/mL)
Estradiol (E2) measures the most potent form of estrogen, the hormone central to the menstrual cycle, bone maintenance, and many aspects of metabolic health. Women test it to investigate irregular cycles, fertility questions, or perimenopausal symptoms, with results interpreted against the phase of the cycle in which blood was drawn.
Reference ranges
Commonly used adult reference ranges. Labs vary in methodology and cutoffs, interpret your results against your lab report's stated ranges and with your doctor.
Adult female follicular-phase ranges shown; estradiol varies widely across the cycle and drops after menopause, so cycle timing is essential to interpretation.
| Zone | Range |
|---|---|
| Low | 0–30 pg/mL |
| Follicular range | 30–150 pg/mL |
| High | 150–250 pg/mL |
The importance of Estradiol
Estradiol is produced mainly by the ovaries and orchestrates the menstrual cycle: it builds through the follicular phase, spikes to trigger ovulation, and rises again mid-luteal phase.[1] Because of this built-in rhythm, an estradiol result means little without knowing the cycle day, the same number can be normal on day 3 and low on day 12.
Beyond reproduction, estradiol supports bone density, vascular flexibility, skin, and aspects of mood and cognition.[2] The wide hormonal swings of perimenopause and the sustained low levels after menopause are associated with hot flashes, sleep disruption, and accelerating bone loss[3], context in which estradiol testing is often paired with FSH.
Very low estradiol in a premenopausal woman can also reflect intense training, low energy availability, or hypothalamic suppression, patterns common in athletes.[4] Whether the question is cycle health, perimenopause, or fertility, results are best interpreted with cycle timing in hand and reviewed with your doctor.
Part of our complete guide to Women's Health Lab Tests — browse every panel and biomarker guide in this hub.
Frequently asked questions
What is a normal estradiol level?
For premenopausal women in the follicular phase, commonly used reference ranges run roughly 30–150 pg/mL, rising far higher around ovulation and falling below about 30 pg/mL after menopause. Because the range shifts with cycle phase, results are interpreted against the day of your cycle at the draw.
When in my cycle should I test estradiol?
It depends on the question. Baseline hormone assessments are typically drawn on cycle day 2–4, when estradiol is at its predictable low; fertility protocols may test at other specific points. Recording your cycle day at the draw makes any result far more interpretable.
What does low estradiol mean?
In premenopausal women, low estradiol can reflect the normal early-cycle trough, perimenopause, intense exercise with low energy availability, or hypothalamic suppression from stress or undereating. In the menopausal transition, low values alongside high FSH fit the expected pattern. The right interpretation depends on age, symptoms, and cycle timing, worth reviewing with your doctor.
Do men need estradiol testing?
Sometimes. Men produce estradiol by converting testosterone, and levels outside the typical male range (roughly 10–40 pg/mL) are associated with symptoms ranging from low libido to breast tissue changes. It is most often checked in men on testosterone therapy, using a male-specific assay and range.
References
- [1] The Normal Menstrual Cycle and the Control of Ovulation — Endotext, NCBI Bookshelf (NIH)
- [2] Estradiol — StatPearls, NCBI Bookshelf (NIH)
- [3] Hot Flashes: What Can I Do? — National Institute on Aging (NIH)
- [4] The Female Athlete Triad/Relative Energy Deficiency in Sports (RED-S) — Revista Brasileira de Ginecologia e Obstetrícia
Reviewed by
Jason August
Founder & Editorial Lead
Jason August is the founder of Metabolic Markers and its parent company, Advancing Development. He has spent his career building and scaling real-world ventures, including as a founding team member at Build-A-Bear Workshop during its growth from startup to global public company, and since then across capital, real estate, adaptive reuse, and hospitality. He founded Metabolic Markers to make blood-biomarker testing easier to understand and access, and oversees the site’s content and editorial accuracy. Jason is not a medical professional; all content on this site is educational, reviewed for accuracy, and never a substitute for advice from a licensed physician.
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