What day of your cycle should you test hormones?
The short answer
Test FSH and estradiol (often with LH) early in your cycle, around day 3, counting the first day of your period as day 1. Test progesterone about 7 days before your next period is due to check for ovulation; that is day 21 only in a 28-day cycle. AMH can be tested on any day.
What to do
- Count the first day of your period as day 1.
- Book FSH, LH and estradiol for around day 3.
- For progesterone, count back about 7 days from the date you expect your next period.
- Book AMH on any day that suits you.
- On hormonal birth control? Tell whoever reviews your results, because cycle-day timing may not apply.
- If your cycles are irregular, ask your clinician how to time the test.
Which results it changes
| Marker | Effect | How long |
|---|---|---|
| FSH[1] | Read alongside estradiol from the same early-cycle draw | Test around cycle day 3 |
| Estradiol[1] | Drawn with day 3 FSH so the two can be read together | Test around cycle day 3 |
| Progesterone[2][3] | Used to confirm ovulation | Mid-luteal: about 7 days before your next period (day 21 of a 28-day cycle) |
| AMH[1] | No cycle timing needed | Any day of the cycle |
| FSH, LH and estradiol[4] | Lower during hormonal contraception | While using hormonal birth control |
| Total and free testosterone[5] | Lower on combined birth control pills (free testosterone about 61% lower on average) | While taking the pill |
| SHBG[5] | Higher on combined birth control pills | While taking the pill |
How to count cycle days
Day 1 is the first day of your period (proper bleeding, not light spotting). Count forward from there. "Day 3" and "day 21" are shorthand from fertility testing for two parts of the cycle: the early follicular phase, just after your period starts, and the mid-luteal phase, about a week after ovulation.
Cycles differ in length mainly because the first half, before ovulation, varies. The second half, after ovulation, is more consistent at about 14 days. That is why the timing rules below are anchored to your period, not to a fixed calendar day.
Around day 3: FSH, LH and estradiol
FSH is the main early-cycle test, and fertility guidance says a day 3 FSH result should always be read alongside estradiol. So the two are usually drawn together on the same visit. LH is often added to the same draw; you can order the FSH & LH test as one.
If day 3 falls on a weekend or holiday, ask whoever ordered the test, or will interpret it, whether a nearby day is fine. Quest patient service centers have set hours, so check them when you book.
Progesterone: about a week before your period, not always day 21
A progesterone blood test is the usual way to confirm that you ovulated, and guidance often calls it the "day 21" test. Day 21 assumes a 28-day cycle with ovulation around day 14.
Because the phase after ovulation runs about 14 days, the real target is its middle: about 7 days before your next period is expected. In a 28-day cycle that is day 21. In a 32-day cycle it is about day 25, and in a 35-day cycle about day 28.
If your period then comes much earlier or later than you expected, the draw may have missed the window. Your clinician may suggest repeating it in another cycle.
AMH: any day
AMH does not need to be timed. A fertility consensus statement says it can be measured on a random basis, so you can book it whenever it suits you. Many people add it to their day 3 draw to save a trip.
Testosterone and SHBG
There is no set cycle day for testosterone or SHBG. If you are tracking them over time, test at a similar point in your cycle and at a similar time of day each time, so results are easier to compare.
Combined birth control pills change both. A meta-analysis found that they lower total and free testosterone, with free testosterone down about 61% on average, and raise SHBG. Results on the pill are not comparable with results off it.
If you use hormonal birth control
Cycle-day timing is built around a natural cycle. During hormonal contraception, FSH, LH and estradiol are lower than usual, so day 3 rules may not apply. Studies disagree on whether hormonal contraception lowers AMH.
Do not stop your birth control to get a test. Tell your clinician which method you use, and ask how they want the test timed.
Frequently Asked Questions
More on preparing
Sources
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- Lindsay TJ, Vitrikas KR. Evaluation and treatment of infertility. Am Fam Physician. 2015 Mar 1;91(5):308-14. PMID: 25822387. PubMed
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- D'Arpe S, Di Feliciantonio M, Candelieri M, Franceschetti S, Piccioni MG, Bastianelli C. Ovarian function during hormonal contraception assessed by endocrine and sonographic markers: a systematic review. Reprod Biomed Online. 2016 Oct;33(4):436-448. doi: 10.1016/j.rbmo.2016.07.010. PMID: 27527655. PubMed
- Zimmerman Y, Eijkemans MJ, Coelingh Bennink HJ, Blankenstein MA, Fauser BC. The effect of combined oral contraception on testosterone levels in healthy women: a systematic review and meta-analysis. Hum Reprod Update. 2014 Jan-Feb;20(1):76-105. doi: 10.1093/humupd/dmt038. PMID: 24082040. PubMed
Content reviewed for accuracy by the JustLabs editorial team.
Educational information, not medical advice. Don’t stop or change a prescribed medicine without talking to your prescriber. If your lab order gives different instructions, follow your lab order.