Progesterone
A key reproductive hormone for menstrual health, fertility, and pregnancy. Timing your test correctly is half the battle.
Progesterone rises after ovulation and is essential for maintaining a pregnancy. Testing it at the right time in your cycle tells you whether you're ovulating properly — one of the first things checked in any fertility workup.
What is this test?
Progesterone is a hormone produced mainly by the corpus luteum — the structure left behind in your ovary after it releases an egg. Before ovulation, progesterone is near zero. After ovulation, it surges, peaking about 7 days later. This rise is what confirms you actually ovulated.
Progesterone prepares your uterine lining for a fertilised egg and sustains early pregnancy. If no pregnancy occurs, progesterone drops, triggering your period. Testing it at the right time in your cycle is critical — a random test is almost useless.
What your number means
| Phase / Context | Expected range |
|---|---|
| Follicular (day 1–14) | < 1 ng/mL |
| Mid-luteal (day 21) | > 10 ng/mL confirms ovulation |
| Luteal peak | 10–25 ng/mL (optimal for conception) |
| Early pregnancy | 10–44 ng/mL (first trimester) |
| Men | < 1 ng/mL |
| Postmenopausal | < 1 ng/mL |
Test on day 21 of a 28-day cycle (or 7 days before your expected period if your cycle is longer). Testing at the wrong time will give you a misleadingly low result.
How to support healthy progesterone
- Manage stress — chronic stress raises cortisol, which competes with progesterone for the same precursor (pregnenolone). This "pregnenolone steal" can lower progesterone
- Get enough sleep — progesterone is intimately linked to sleep quality. Poor sleep disrupts the HPO axis
- Maintain a healthy weight — both underweight and overweight status impair ovulation and progesterone production
- Vitamin B6 — supports corpus luteum function and has modest evidence for raising luteal progesterone
- Vitex (chasteberry) — some evidence for improving luteal phase progesterone, especially in women with PMS
- Bioidentical progesterone — prescribed for confirmed luteal phase deficiency or early pregnancy support
Track your cycle hormones over time
eterni connects progesterone, estradiol, LH, and FSH into one view — so you see how your cycle is actually behaving.
Get early accessFrequently Asked Questions
When should I test progesterone?
For fertility assessment, test on day 21 of a 28-day cycle (7 days after expected ovulation). If your cycle is longer or irregular, test 7 days before your expected period. A level above 10 ng/mL confirms ovulation occurred. Random testing is less useful because progesterone fluctuates dramatically across the cycle.
What does low progesterone mean?
Low progesterone in the luteal phase (below 10 ng/mL on day 21) suggests anovulation — your ovary did not release an egg that cycle. This is one of the most common causes of difficulty conceiving. It can also cause short luteal phases, spotting before your period, PMS, and early miscarriage.
Can men need a progesterone test?
Rarely. Men produce small amounts of progesterone from the adrenal glands and testes. It is occasionally tested in male hormone panels when investigating adrenal function or as a precursor in steroid hormone synthesis. Normal male progesterone is typically below 1 ng/mL.
Does progesterone affect mood?
Yes. Progesterone and its metabolite allopregnanolone act on GABA receptors in the brain, producing calming and sleep-promoting effects. The sharp drop in progesterone before your period is thought to contribute to PMS symptoms like irritability, anxiety, and insomnia. Some women are particularly sensitive to these fluctuations.
Progesterone and the luteal phase
After ovulation, the empty follicle transforms into the corpus luteum, which secretes progesterone for about 12–14 days. This luteal phase progesterone does three critical things:
- Transforms the endometrium — converts the uterine lining from proliferative to secretory, making it receptive to embryo implantation
- Maintains early pregnancy — sustains the lining until the placenta takes over progesterone production (around week 8–10)
- Modulates the immune system — shifts the immune response to tolerate the embryo
A luteal phase shorter than 10 days, or progesterone below 10 ng/mL at mid-luteal, may indicate luteal phase deficiency — a treatable cause of infertility.
PCOS and progesterone
Polycystic ovary syndrome (PCOS) — estimated to affect 10–15% of Indian women — is the most common cause of anovulation and therefore low progesterone. In PCOS, follicles develop but don't fully mature or release an egg, so the corpus luteum never forms and progesterone stays low.
If you have irregular periods and low mid-luteal progesterone, PCOS should be high on the differential.
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