Hormones After 40: What to Actually Test (And What "Fine" Doesn't Mean)

"Your bloodwork is normal" doesn't mean your hormones are. Here's the panel that actually tells you where you are in the menopause transition — and why FSH is the number you've been missing.

TL;DR

• A single-day estrogen test in a perimenopausal woman is nearly useless — estradiol oscillates substantially across the perimenopause transition while FSH climbs in a more linear pattern (Randolph 2011, JCEM).
• FSH is the more reliable marker for where you are in the transition — it climbs and stays climbed, while estradiol oscillates (Park 2021, Int J Environ Res Public Health).
• FSH levels above ~25 IU/L tracking against bone loss and lean mass changes in cross-sectional data (Park 2021, Jankowski 2020).
• "Normal" lab ranges for hormones are built off cycling women and postmenopausal women — perimenopause sits in the gap and frequently gets misread as "fine."
• You don't need every hormone tested. You need the right five, run twice, ideally on cycle day 3 if you're still cycling.

Why your doctor said you're fine and you're still not

You're 43. You're tired in a way coffee doesn't fix. Your sleep is fragmented. Your workouts feel heavier. You've gained a few pounds around your middle that diet hasn't moved. Your periods are getting weird — closer together, then further apart, heavier some months, lighter the next.

You go to your doctor, get bloodwork, and the message back is: "Everything looks good. Your hormones are normal." You leave the office knowing something is off and being told nothing is.

Here's what's actually going on. Most primary care panels in this scenario test TSH, sometimes a single estradiol, sometimes FSH if you push for it. Those results get checked against "normal" reference ranges — which were built from a mix of cycling women in their 20s–30s and postmenopausal women in their 60s. Perimenopause is the transition between those two states and doesn't fit either reference cleanly.

So a 43-year-old with an estradiol of 80 pg/mL and an FSH of 28 IU/L gets told she's "normal" — when in reality she's in mid-perimenopause and her bone, muscle, and brain are already responding to it.

Why FSH beats estrogen as the marker

Estrogen is what most women have heard of. It's also the worst single number for figuring out where you are in the menopause transition.

Estradiol levels in perimenopause oscillate substantially. The SWAN longitudinal data — including the Randolph 2011 analysis of FSH and estradiol change across the menopausal transition — show that estradiol levels in late perimenopause can swing widely while FSH climbs in a steadier upward trajectory (Randolph 2011, JCEM). A single estradiol draw tells you what your ovary did this morning — not what it's been doing for the last six months.

FSH is different. As ovarian reserve declines, the pituitary pumps out progressively more FSH trying to recruit follicles. FSH rises persistently across the transition and stays elevated. It's the more reliable single marker of stage (Park 2021).

And FSH isn't just a passive bystander. The 2021 cross-sectional analysis of healthy Korean women showed that bone mineral density at the hip and spine tracked FSH levels independent of estradiol — meaning the hormonal predictor of bone loss in late perimenopause was the rising FSH, not the falling estrogen (Park 2021). The University of Colorado lean-mass data lines up the same way: appendicular lean mass in late-perimenopausal women correlates with FSH, not estradiol (Jankowski 2020).

If you're going to test one thing, test FSH. If you're going to test it once, test it twice, two cycles apart.

The five hormones that matter at 40+

You don't need a 60-marker boutique panel. You need these five, run correctly:

1. FSH (Follicle-Stimulating Hormone)

The marker of where you actually are in the transition. Test on cycle day 2–4 if you're still cycling. FSH above ~25 IU/L on day 3 suggests late-perimenopause. Above 30 sustained = postmenopause.

2. Estradiol (E2)

Useful for context, not for decision-making in isolation. Run alongside FSH on the same day. If E2 is low and FSH is high, that's a postmenopausal pattern. If both are high, that's a late-perimenopause LH/FSH surge week.

3. Thyroid panel — TSH, free T4, free T3

Thyroid dysfunction mimics perimenopause almost perfectly: fatigue, weight gain, hair changes, mood. A TSH alone is not enough — you need free T4 and free T3 to see the full picture.

4. Fasting insulin + fasting glucose (calculate HOMA-IR)

Perimenopause is a metabolic event, not just a hormonal one. Insulin sensitivity drops measurably across the transition. A fasting glucose alone can look normal while fasting insulin has been climbing for years. The HOMA-IR calculation (insulin × glucose / 405) is what tells you the truth.

5. Vitamin D (25-OH)

Not a sex hormone, but it functionally behaves like one. Vitamin D under 30 ng/mL impairs muscle function, bone remodeling, and immune signaling. The vast majority of women over 40 not actively supplementing test below this threshold.

That's the panel. Five markers, one blood draw if you're postmenopausal, two draws across two cycles if you're still cycling.

What "in range" doesn't mean

The most common failure mode in perimenopausal care is the "everything's normal" call when everything is, in fact, optimally suboptimal.

• TSH of 3.8 is "in range" (most labs go up to 4.5). It's also associated with measurably more fatigue and weight issues than a TSH of 1.5. Many endocrinologists treat above 2.5 in symptomatic patients.
• Fasting insulin of 14 is "in range" (most labs go up to 25). It's also profoundly insulin-resistant. Optimal is under 8.
• Vitamin D of 32 ng/mL is "in range" (cutoff is usually 30). Optimal for bone and muscle is 40–60.
• FSH of 22 IU/L at 44 is "in range" for premenopause. It's also unmistakably perimenopausal and worth treating differently than the 28-year-old you're being compared to.

The reference range isn't optimal — it's two standard deviations of a population that includes a lot of unhealthy people. "Normal" means "you're not in the bottom 2.5% of the population." It doesn't mean "you're in the range where your body actually works."

What to do this week

If you're 40+ and your doctor said you're "fine" but you don't feel fine:

• Day 1: Write down what you're experiencing. Not feelings — observables. Sleep latency. Wake-ups. Energy at 10 AM vs 3 PM. Workout recovery. Period changes. The pattern matters more than any single morning.
• Day 2: Pull your last bloodwork. Find the actual numbers, not the "normal" flags. Look at TSH, FSH (if drawn), vitamin D, fasting glucose, fasting insulin if you have it.
• Day 3: Schedule a comprehensive panel. The five above, fasting, on cycle day 2–4 if you're cycling. Bring this list with you so the right boxes get checked.
• Day 4: Read your previous panel against the optimal ranges in this article, not the lab ranges.
• Day 5–7: Start the basics that don't need a lab to confirm. Protein floor. Two lifting sessions. Sleep window. Walking.

You'll have data and a baseline. That's the difference between treating yourself and being told you're fine.

The bottom line

Perimenopause is not invisible to lab work. It's just invisible to the wrong lab work, compared against the wrong reference ranges.

FSH is the marker that catches it. The thyroid and metabolic markers tell you what else is layered on top. And "in range" is not a synonym for "optimal" — your body knew that before the lab did.

The work after the numbers is the same as the work without them: heavy lifting, protein, sleep, walking. But knowing where your hormones actually sit changes how aggressively you build the rest of the protocol around them.

References

1. Randolph JF Jr, Zheng H, Sowers MR, et al. Change in Follicle-Stimulating Hormone and Estradiol Across the Menopausal Transition: Effect of Age at the Final Menstrual Period. J Clin Endocrinol Metab. 2011;96(3):746-754. PMC3047231

2. Park YM, Jankowski CM, Swanson CM, Hildreth KL, Kohrt WM, Moreau KL. Bone Mineral Density in Different Menopause Stages is Associated with Follicle Stimulating Hormone Levels in Healthy Women. Int J Environ Res Public Health. 2021;18(3):1200. PMC7908273

3. Jankowski CM, Wolfe P, Schmiege SJ, et al. Appendicular lean mass is lower in late- compared with early-perimenopausal women. J Appl Physiol. 2019;127(5):1224-1230. PMC7272749

4. Greendale GA, Sowers M, Han W, et al. Bone mineral density loss in relation to the final menstrual period in a multiethnic cohort: results from the Study of Women's Health Across the Nation (SWAN). J Bone Miner Res. 2012;27(1):111-118. PubMed 21976317