Treatments · before your appointment

Blood tests on HRT — when they help, when they don't, and what to ask for.

Bloods can be useful in specific situations and unhelpful in many others. Here's the short version of what NICE, BMS and the Menopause Society actually say, so you can walk in knowing which tests to ask for and which to skip.

What the guidelines actually say

01
The headline
For most people on HRT, routine blood monitoring isn't required. Symptoms — not numbers — guide the dose.
NICE NG23, the British Menopause Society and the Menopause Society (NAMS) all say the same thing: HRT is titrated to symptom response, not to a target blood level. If your hot flashes are gone, your sleep is better, your mood is steadier and the bleeding pattern is what it should be for your regimen, that's the data that matters. A 'normal' estradiol number on a panel doesn't mean you don't need more, and a 'high' one in a well-absorbing woman with no side effects isn't a problem on its own.
02
When bloods genuinely help
A short list: confirming early menopause under 45, troubleshooting transdermal absorption, checking thyroid or iron when symptoms don't add up, baseline bone risk markers.
There are real situations where a blood test changes the plan. Suspected premature ovarian insufficiency (POI) — under 40, sometimes under 45 — needs two FSH readings four to six weeks apart, off contraception where possible. If you're on a high-dose transdermal patch or gel and symptoms aren't budging, an estradiol level can confirm whether you're actually absorbing. Thyroid (TSH, free T4), ferritin, vitamin D, B12 and HbA1c are worth checking when fatigue, brain fog or mood feel out of proportion to the menopause picture. And if osteoporosis risk is on the table, DEXA plus relevant blood markers (calcium, vitamin D) is a separate clinical question, not menopause monitoring.
03
When bloods don't help (and can mislead)
FSH on HRT, FSH on the combined pill, one-off estradiol levels without context, and most clinic 'comprehensive hormone panels'.
Once you're on HRT, FSH is no longer a useful diagnostic — the hormones suppress it. The same goes for the combined oral contraceptive. A one-off estradiol level taken at a random time of day, without knowing your delivery method and timing, is hard to interpret and shouldn't trigger a dose change on its own. 'Comprehensive hormone panels' (often advertised privately, sometimes saliva or finger-prick) typically test things — DHEA, pregnenolone, urine metabolites — that don't change how a menopause-trained doctor titrates HRT. They're not wrong to exist; they're just rarely the bottleneck.
04
Timing rules that change the result
Patches and gels: test on a steady-state day, several hours after application. Oral estradiol: trough vs peak matters. Progesterone: timing depends on regimen.
Transdermal estradiol (patch or gel) should be tested after at least two weeks on a stable dose, ideally 24 hours after gel application or mid-patch-cycle for a steady-state read. Oral estradiol levels swing more sharply, so a single random reading is less informative — your doctor may ask for a trough sample (just before the next dose). Progesterone timing depends on whether you're on continuous or cyclical, and oral micronized progesterone peaks within a few hours then drops, so a random reading often looks low even when the dose is right. The honest answer: if a blood test is being ordered, ask what timing the lab needs, before the appointment.
05
Testosterone, specifically
If testosterone is being added or considered, baseline total testosterone and SHBG plus a follow-up at 3 months is the conventional pattern.
Testosterone for low libido in postmenopause (Global Consensus Position Statement, 2019) is dosed off-label in most countries and is one of the areas where blood monitoring genuinely matters — both to confirm you're in physiological range and to catch supraphysiological levels that drive side effects. The usual shape is a baseline total testosterone and SHBG, then a repeat at around three months, then periodically. This is the one HRT-adjacent prescription where 'check the bloods' is actually the standard of care.
06
What to ask for at the appointment
Be specific about why you're asking. Vague 'can you check my hormones?' gets vague tests; specific concerns get useful ones.
If symptoms are stuck, frame it that way: 'I'm on X dose for Y weeks and the hot flashes aren't budging — can we check absorption?' If fatigue isn't shifting, ask for TSH, ferritin and vitamin D rather than 'a hormone panel'. If testosterone is on the table, ask for total testosterone and SHBG with timing. And if a private clinic offers a £200 panel before they'll prescribe anything, it's reasonable to ask which decisions the results will actually change.