Hormone Replacement Therapy and Cycle Timing

Do You Need to Time Your Labs With Your Cycle for HRT?

Hormone replacement therapy (HRT) can be life changing for many women navigating the often turbulent waters of perimenopause and menopause. But before we talk about pellets, patches, or troches, let’s zoom out and ask a fundamental question I’m often asked:

“Do I need to time my labs with my cycle before starting or adjusting HRT?”

The answer? Like most things in women’s health: it depends.

Let’s unpack the why behind the timing of hormone testing and how to tailor it to your unique hormonal fingerprint.

Why Timing Might Matter (Especially If You’re Still Cycling)

If you’re still menstruating whether regularly or with the occasional surprise the timing of your bloodwork absolutely matters.

Here’s why:

• Hormone levels fluctuate dramatically throughout the menstrual cycle. Estrogen peaks just before ovulation (mid-cycle), while progesterone hits its high point about a week after (around day 21 of a typical 28-day cycle).

• Testing on the wrong day may misrepresent your baseline and lead to over- or under-prescribing.
  

For most menstruating women, it’s recommended to test during the second half of your cycle or on cycle day 19-21 (counting day 1 as the first day of your period). This gives us a snapshot of your mid-luteal phase, when both estrogen and progesterone should be in balance should being the operative word.

This window help assess whether your body is making enough progesterone (hint: many of you aren’t after age 35) and whether estrogen is working for you or against you (cue symptoms like breast tenderness, mood swings, and heavy bleeding).

But What If You’re Postmenopausal or Have Irregular Cycles?

If your periods are MIA or you can’t remember the last time they showed up on schedule cycle timing becomes less relevant. Once you’re postmenopausal (defined as no periods for 12 months), your hormones tend to flatten out into a new baseline.

In that case, lab timing is less about “when” and more about why you’re testing in the first place:

• Are you checking to establish a baseline before starting HRT?
  

• Are you already on HRT and trying to fine-tune your dose?
  

• Are you tracking symptom resolution (e.g., insomnia, hot flashes, libido) in parallel with lab values?

Remember: labs are a tool not a dictator. Treat the woman, not the number.

Which Hormones Should You Even Test?

When evaluating HRT needs, I often test:

• Estradiol (E2)

• Progesterone

• FSH (Follicle-Stimulating Hormone)

• DHEA-S

• Total and Free Testosterone

• Thyroid Panel (TSH, Free T4, Free T3, and antibodies)

• Cortisol (saliva or DUTCH test for diurnal rhythm)
  

Each woman’s plan will vary. The woman who’s been biohacking for years and tracks every symptom in her Oura ring app? Different approach than the one just trying to get through the day without crying in a Starbucks parking lot.

The Bottom Line: Be Strategic, Not Rigid

In cycling women, test in the second half of your cycle or more accurately in the mid-luteal phase (days 19–21) for the clearest picture.
In postmenopausal women, timing is less critical, but consistency (e.g., same time of day, fasting vs. non-fasting) helps.

And never forget: symptoms lead. Labs follow.

One More Thing…

If your doctor brushes off your concerns because “your labs are normal,” but you feel anything but keep digging. The standard lab ranges weren’t designed for optimal hormone balance; they were designed for population averages. They should be interested in your personal optimal.

Because the truth is, HRT is both art and science. And you deserve a practitioner who sees you, not just your lab slip.

And remember: your hormones are talking. The question is are you listening?