Perimenopause or thyroid? How to tell them apart

Thyroid problems are common in women, and they can start around the same age as perimenopause: the NHS says Hashimoto's disease, the most common cause of an underactive thyroid in the UK, is most common in women and usually starts between 30 and 50. The thyroid controls your metabolism, so when it runs too slow (hypothyroidism) or too fast (hyperthyroidism), you feel it everywhere. So does the hormonal rollercoaster of perimenopause.

One Filipina on Reddit summed it up: she could no longer tell what she was feeling because everything had blended together, "since meron pa pcos/hypo" (r/kwarentahin). That is exactly why testing helps.

The diagram above shows which symptoms belong to each and which sit in the middle. In short:

Common to both

• Tiredness and low energy
• Weight gain or weight change
• Mood swings, anxiety or low mood
• Poor sleep
• Brain fog and trouble concentrating
• Hair thinning
• Period changes (heavier, lighter or irregular)
• Palpitations (especially with an overactive thyroid)

More typical of perimenopause

• Hot flashes and night sweats that come in waves
• Vaginal dryness and pain with sex
• Cycle changes that fit your age (usually the 40s)
• Waking at 3 am drenched, then cold

More typical of thyroid problems

• Underactive: feeling colder than usual, constipation, dry skin and hair, a hoarse voice
• Overactive: heat sensitivity and heavy sweating (not in waves), weight loss despite a bigger appetite, trembling, a fast or irregular heartbeat, diarrhoea, thirst
• A visible swelling in the front of the neck (goitre)

These lists follow the NHS thyroid pages. They are tendencies, not rules. Only a test can tell.

• TSH (thyroid-stimulating hormone) is the usual first test. If TSH is high, your thyroid may be underactive. If it is low, your thyroid may be overactive.
• FT4 (free thyroxine) is often added to confirm what TSH suggests.
• Your doctor may add thyroid antibodies or other tests depending on the result.

For perimenopause itself, blood tests are often not needed. NICE NG23 says that over 45 with typical symptoms, perimenopause can be diagnosed without hormone tests, and it advises against using estradiol, AMH or similar tests to diagnose it at that age, since hormone levels like FSH swing up and down during perimenopause (NICE NG23 and QS143). Between 40 and 45 with symptoms, including a change in your cycle, your doctor may consider an FSH test; under 40, it is used when early menopause (POI) is suspected. See the FSH test guide.

Other tests worth discussing if you are very tired or foggy: a complete blood count (for anaemia), vitamin B12, and blood sugar.

• TSH at Exact Check: ₱490 per test (Exact Check)
• FT4 at Exact Check: ₱470 per test (Exact Check)
• TSH at other labs: ₱600 to ₱1,100 per test (Hi-Precision, Healthway (estimates))

For comparison, if your doctor also orders hormone tests:

• FSH: ₱855 per test (Exact Check) or ₱1,000 per test (Hi-Precision via Hati Health)
• Estradiol: ₱1,325 per test (Exact Check)

The other-lab TSH range is an estimate from an aggregator and should be confirmed with the lab. Some labs need a doctor's request; many do not for basic tests. You can book tests through Hati Health.

Prices checked October 2026. See costs for everything else.

You can. A treated thyroid problem and perimenopause can happen together, and treating one will not fix the other. If your thyroid result is normal, or your thyroid is already treated and you still have hot flashes, night sweats or cycle changes, talk to your doctor about perimenopause and the options for it: HRT for menopause or non-hormonal treatments.

If you take thyroid medicine and start hormone therapy, your doctor may recheck your thyroid levels after a while, because estrogen tablets raise the protein that carries thyroid hormone in the blood and may increase how much thyroid medicine you need (Mazer, Thyroid 2004). Skin gel has less of this effect, as the review explains it is linked to estrogen passing through the liver first.

If you have had polycystic ovary syndrome (PCOS), the picture gets more tangled: irregular periods, weight changes and hair changes can come from PCOS, thyroid or perimenopause. Our sister site pcosphilippines.com explains PCOS after 40 and how it changes around menopause.

To sort your symptoms before your visit, try the symptom checker and keep a symptom diary for a few weeks. Bring both to a doctor; see find a doctor.