Hormone Testing & Optimization Hub: Labs, Ranges, and What Your Results Mean

Welcome to the Hormone Testing & Optimization Hub.

This is the canonical guide for understanding hormone labs, how to time them, what common patterns mean, and what to do next.

• Estradiol (E2): primary estrogen during reproductive years

• Progesterone: confirms ovulation and luteal phase strength

• LH + FSH: pituitary signals that drive ovarian function

• Total testosterone

• SHBG

• Free Androgen Index (FAI) (calculated)

• TSH (signal)

• Free T4 (output)

• Free T3 (active hormone, sometimes helpful)

• Consider thyroid antibodies when symptoms persist with “normal” screening labs

Hormones fluctuate.

• A result can be “normal” one day and very different a week later.

• For menstruating people, interpret E2 and progesterone in the context of cycle day.

Reference ranges reflect what is common in a lab population. They are not personalized goals.

Single values are snapshots. Patterns across multiple markers, symptoms, and trends over time usually matter more.

Estrogen and progesterone work like a monthly relay.

• Estrogen builds and prepares (follicular phase).

• Progesterone stabilizes and supports (luteal phase).

These are common patterns worth discussing with a clinician:

• High estrogen relative to progesterone: heavy/painful periods, bloating, breast tenderness, irritability

• Low estrogen: hot flashes, night sweats, vaginal dryness, fatigue, low mood

• Low progesterone: anxiety, poor sleep, spotting, headaches, shorter luteal phase

• Day 3 labs (baseline ovarian signal): often includes FSH, LH, estradiol.

• Mid-luteal progesterone: test ~7 days after ovulation (not always “day 21”).

• > 5 ng/mL often confirms ovulation.

• Many clinicians like to see > 10 ng/mL for a stronger luteal phase.

• Blood (serum): best for standardized measurement at a point in time.

• Saliva: sometimes used for rhythm-focused hormones, but less standardized.

• Dried urine (DUTCH): adds metabolites and pathways, but costs more and needs expert interpretation.

Estradiol is the most potent estrogen during reproductive years.

• Levels vary by cycle phase and life stage.

• A value that is normal at ovulation can be abnormal on day 3, or after menopause.

• Relative progesterone deficiency (“estrogen dominance”)

• Higher body fat (estrogen production in adipose tissue)

• Reduced estrogen clearance (liver and gut factors)

• Perimenopause/menopause transition

• Very low energy availability, intense training, or low body weight

Perimenopause is often defined by irregular ovulation.

• No ovulation means no corpus luteum.

• No corpus luteum means low progesterone that cycle.

This is why a single progesterone test can be misleading in perimenopause. Symptom tracking plus repeated, well-timed labs are usually more informative.

FAI estimates bioavailable testosterone using total testosterone and SHBG.

FAI = (Total Testosterone / SHBG) × 100 (units must match, typically nmol/L)

It can explain symptoms when total testosterone looks “fine,” but SHBG is high or low.

Often associated with hyperandrogenism and may be seen in PCOS patterns.

A useful mental model:

• TSH = brain’s signal

• Free T4 = thyroid output

• Free T3 = active hormone (often converted from T4)

Ask your clinician about:

• TPOAb / TgAb antibodies (autoimmune thyroid patterns)

• Medication and supplement effects (notably biotin)

Yes. That pattern is often described as estrogen being high relative to progesterone.

There isn’t one. The right day depends on the hormone and what question you are trying to answer.

These pages are now incorporated here (and should 301 redirect to this hub):

• /blog/estradiol-levels-in-women

• /blog/progesterone-levels-perimenopause

• /blog/free-androgen-index

• /blog/how-to-interpret-thyroid-function-test-results