Progesterone is one of the most cycle-dependent hormones in the body. The same woman can have a value under 1 ng/mL on day 5 of her cycle and above 15 ng/mL on day 21 — both perfectly normal. Most of the confusion about progesterone labs comes from results being reported and interpreted without that context. This page lays out the actual reference ranges by phase, age, and reproductive status, with a practical guide to how to test and what the numbers tell you.
Progesterone Reference Ranges by Phase
Reference ranges vary slightly between labs, but the clinically useful picture looks like this:
| Phase / Status | Typical Range (ng/mL) | Notes |
|---|---|---|
| Follicular phase (days 1–14) | < 1.0 | Baseline; rises sharply after ovulation |
| Ovulation (day ~14) | 1–3 | Transition zone |
| Mid-luteal (day ~21, 28-day cycle) | 5–20 | >10 strongly suggests ovulation |
| Late luteal (just pre-period) | 1–5 | Falling sharply |
| Perimenopause (variable) | < 1 to 15 | Cycle-to-cycle variability is the rule |
| Postmenopause | < 0.5 | Baseline adrenal contribution only |
| Postmenopause on HRT (oral) | 1–5 (highly variable) | Driven by dose and timing |
Conversion: 1 ng/mL = 3.18 nmol/L. International labs report in nmol/L.
How Progesterone Changes Through the Cycle
The classic textbook curve, simplified:
- Days 1–7 (early follicular). Progesterone is barely detectable.
- Days 7–13 (late follicular). Still under 1 ng/mL.
- Day 14 (ovulation). A brief rise to about 1–3 ng/mL.
- Days 15–21 (early to mid-luteal). Progesterone climbs as the corpus luteum produces it. By day 21, levels peak at 5–20 ng/mL in ovulatory cycles.
- Days 22–28 (late luteal). If no implantation occurs, levels fall sharply, triggering menstruation.
A flat curve — no clear rise between follicular and luteal samples — is the hallmark of an anovulatory cycle.
Normal Progesterone Levels in Perimenopause
Perimenopause is defined hormonally by erratic ovulation, and progesterone is the hormone that reflects that erraticness most directly. In one cycle the corpus luteum may produce a robust mid-luteal level of 12 ng/mL; in the next cycle, ovulation may not happen at all and progesterone never rises out of baseline. The result is a hormonal terrain that does not look like the textbook curve, and a single lab value drawn on a single day can be deeply misleading.
Practical implication: in a perimenopausal woman with clear symptoms, treat the pattern, not the single number. A clinician trained in modern hormone care will not require a "low" progesterone lab to address perimenopausal sleep disruption, anxiety, and heavy periods.
Normal Progesterone Levels After Menopause
Once a woman has gone 12 consecutive months without a period, the ovaries no longer ovulate and progesterone falls to baseline — typically under 0.5 ng/mL, with the small remaining contribution coming from the adrenal glands. This is normal, not pathological.
Postmenopausal women on systemic estrogen therapy with an intact uterus are co-prescribed progesterone for endometrial protection. Lab values on therapy depend on the dose and route and are not particularly useful for guiding the regimen — endometrial monitoring and symptom response are more clinically meaningful.
How and When to Get Tested
Serum Blood Testing
The most standardized option. Draw timing matters: about seven days before the expected next period. If your cycle runs 32 days, that is day 25, not day 21. If you have no idea when ovulation occurs because cycles are irregular, basal body temperature charting or ovulation predictor kits can help, or your provider may order LH testing as an anchor.
Saliva Testing
Reflects free, bioavailable hormone and is particularly useful when topical progesterone is already in use — transdermal cream raises salivary progesterone reliably while sometimes producing only modest serum changes. Less standardized than serum but increasingly used in functional and integrative practices.
Capillary Blood Spot
A finger-prick method that can be done at home and mailed to a lab. Useful for capturing multiple cycle days when serum collection is impractical. Quality and reference ranges vary by lab; choose providers with established validation studies.
Urinary Metabolites
Dried urine testing measures progesterone metabolites and can give a more complete picture of how progesterone is processed and cleared. More expensive and harder to interpret without provider guidance, but valuable when standard testing is inconclusive.
What to Do If Your Levels Are Low
A low result on a properly timed test, combined with a matching symptom pattern, is a clear signal — not a final verdict. The reasonable next steps:
- Confirm the timing was correct relative to your cycle
- Consider repeat testing in 1–2 cycles if borderline
- Investigate contributing factors: stress load, thyroid status, sleep, nutrition
- Discuss bioidentical progesterone therapy with a hormone-trained clinician
- For perimenopausal women, expect symptom-based treatment to take precedence over labs
Frequently Asked Questions
What is a normal progesterone level?
There is no single "normal" — progesterone varies dramatically by cycle phase, age, and reproductive status. In a typical 28-day cycle, follicular-phase levels are under 1 ng/mL, mid-luteal levels run 5–20 ng/mL, and postmenopausal levels return to below 0.5 ng/mL. A value above ~10 ng/mL at day 21 is generally consistent with ovulation.
When during my cycle should progesterone be tested?
About seven days before the expected next period — roughly day 21 in a 28-day cycle, but adjusted proportionally for longer or shorter cycles. Testing earlier in the cycle gives values that look "low" simply because progesterone has not risen yet. A single mid-luteal serum measurement is the most useful single data point.
What is a low progesterone level?
In a mid-luteal sample, below 5 ng/mL strongly suggests anovulation or a meaningful luteal-phase defect. Between 5 and 10 ng/mL is borderline and depends on the rest of the picture. Postmenopausal women normally have values under 0.5 ng/mL, so a "low" reading there is expected, not pathological.
When is progesterone highest in a cycle?
Approximately day 21 of a 28-day cycle, give or take a day — the mid-luteal phase, about seven days after ovulation. The corpus luteum is at peak output. Progesterone then falls quickly in the late luteal phase if pregnancy does not occur, triggering menstruation.
Do progesterone levels change with age?
Yes. Mid-luteal progesterone is typically robust in the 20s and early 30s, begins to decline in the mid-to-late 30s as ovulation becomes less reliable, drops substantially through perimenopause as anovulatory cycles become common, and falls to baseline (under 0.5 ng/mL) after menopause. The downward shift is not linear — perimenopause produces highly variable values from one cycle to the next.
What is the normal progesterone level in perimenopause?
Wildly variable, which is part of what defines perimenopause. A given woman might have a mid-luteal value of 12 ng/mL one cycle (consistent with ovulation) and below 2 ng/mL the next (anovulatory). The clinical implication is that a single low value should not be used to rule a perimenopausal woman in or out — pattern matters more than any single number.
How accurate is progesterone testing?
Serum (venous blood) testing is well-standardized and reproducible when timed correctly to the cycle. Saliva testing is less standardized but captures bioavailable hormone and reflects topical cream use better. Capillary blood spot testing is intermediate. Random timing — drawing a sample on any day of the cycle without regard to ovulation — destroys interpretability regardless of the test used.
Can lab levels be normal even with low-progesterone symptoms?
Yes, particularly in perimenopause. A single well-timed lab can capture an ovulatory cycle while neighboring cycles are anovulatory. In late perimenopause, clinicians often rely on the symptom pattern rather than chasing perfect lab timing — both because cycles are unpredictable and because symptoms respond better to pattern-based treatment than to lab-chasing.
References
- Stricker R, et al. Establishment of detailed reference values for luteinizing hormone, follicle stimulating hormone, estradiol, and progesterone during different phases of the menstrual cycle. — Clinical Chemistry and Laboratory Medicine, 2006.
- Mesen TB, Young SL. Progesterone and the luteal phase: a requisite to reproduction. — Obstetrics and Gynecology Clinics of North America, 2015.
- Santoro N, et al. Reproductive hormones and the menopause transition. — Obstetrics and Gynecology Clinics of North America, 2011.