How Estrogen and Testosterone Work Together to Support Your Cycle and Wellbeing
- Orie Quinn
- Aug 11
- 3 min read
Updated: Aug 21

In women, estrogen-to-testosterone (E/T) ratio is not fixed — it fluctuates significantly across the menstrual cycle because both hormones rise and fall at different times. That said, there are typical ranges that give context for what is considered normal, both in absolute values and in relative balance.
1. Key Points to Understand First
Estrogen in this context usually refers to estradiol (E2), the most potent form.
Testosterone in women is mostly bound to SHBG (sex hormone–binding globulin), and free testosterone is the biologically active portion.
Ratios are usually expressed in pg/mL estradiol to ng/dL testosterone (so the numbers look large if directly divided) or as a relative proportion within the same unit system.
Rather than one “perfect” ratio, the goal is for estrogen to dominate in the follicular and luteal phases, with testosterone peaking mid-cycle to support libido and ovulation.
2. Typical Estrogen & Testosterone Levels by Phase
Cycle Phase | Estradiol (pg/mL) | Total Testosterone (ng/dL) | Approx. E/T Ratio<br>(Estradiol ÷ Testosterone, both in pg/mL) |
Early Follicular (Days 1–5) | 20–80 | 15–45 | ~2:1 to 5:1 |
Late Follicular / Pre-Ovulatory (Days 7–13) | 150–350 (surge) | 25–55 (rises slightly) | ~5:1 to 8:1 |
Ovulation (Day 14 ± 1) | 150–400 | 35–60 (peak) | ~4:1 to 6:1 |
Mid-Luteal (Days 19–23) | 100–250 | 20–45 | ~4:1 to 6:1 |
Late Luteal (Days 24–28) | 50–150 | 15–40 | ~3:1 to 5:1 |
Notes:
The ratio is highest in the late follicular phase when estradiol surges before ovulation.
Testosterone peaks briefly around ovulation but doesn’t surpass estrogen.
If estrogen is too low relative to testosterone, symptoms like acne, hair growth, or cycle irregularity can occur.
If estrogen is too high relative to testosterone, symptoms like bloating, breast tenderness, and low libido may appear.
3. Why Ratio Matters Clinically
Balanced ratio: Supports ovulation, bone health, mood stability, and sexual function.
Low E/T ratio: Often seen in PCOS, androgen excess, or perimenopause; may cause irregular cycles, hirsutism, or low fertility.
High E/T ratio: Seen in estrogen dominance states; may cause PMS, heavy bleeding, and weight gain.
4. Target Healthy Ranges
If measuring estradiol in pg/mL and testosterone in ng/dL, many functional and reproductive endocrinologists look for:
Follicular phase: Estradiol 50–150 pg/mL, Testosterone 25–45 ng/dL → E/T ratio ~4–5:1
Ovulation: Estradiol ~200–300 pg/mL, Testosterone 35–55 ng/dL → E/T ratio ~5–6:1
Luteal phase: Estradiol 100–200 pg/mL, Testosterone 20–40 ng/dL → E/T ratio ~4–5:1
Key Studies with PubMed References
1. Rothman et al. (2011)
“Reexamination of testosterone, dihydrotestosterone, estradiol and estrone levels across the menstrual cycle and in postmenopausal women measured by liquid chromatography‑tandem mass spectrometry.”
Assessed early follicular, mid-cycle (ovulatory), and mid-luteal phases using LC‑MS/MS for more accurate measurement.
Found that serum testosterone, free testosterone, estradiol and SHBG levels all peak at mid-cycle and remain elevated in mid-luteal phase PMC+15PubMed+15MDPI+15.
Supports the concept that testosterone rises at ovulation, while estradiol dominates most of the cycle.
PMID: 21070796
2. Elliott et al. (2003)
“Effect of menstrual cycle phase on the concentration of bioavailable 17‑beta oestradiol and testosterone and muscle strength.”
Compared early follicular vs. mid-luteal phases.
Found no significant change in total testosterone or bioavailable testosterone, while estradiol increased significantly in luteal phase PubMed.
Indicates estradiol-to-testosterone ratio increases during luteal hormone surge.
3. Salivary testosterone across the menstrual cycle (PubMed article)
Reports that testosterone production in women systematically shifts across the menstrual cycle, peaking during the mid-cycle ovulatory window PubMed+15PubMed+15PMC+15.
Suggests the ratio of estradiol to testosterone narrows briefly at ovulation as both rise.
4. JCI Review: Estrogens and Androgens in Women
Noted that serum androgen levels in women are typically higher than estrogen most of the time, except during pre-ovulatory and mid‑luteal phases, when estrogen and androgen levels become more similar JCI.
Adds context that the estrogen/testosterone ratio is most balanced when estrogen surges.