"Should I Get My Thyroid Checked? A Symptom-Pattern Self-Check"
Thyroid disease is one of the easiest things in adult medicine to test for and one of the most commonly missed for years. The blood test (TSH) is cheap, widely available, and accurate. The treatments work. The reason for the delay is almost always that nobody asked.
Symptoms get attributed to stress, depression, perimenopause, getting older, lifestyle, eating, sleep — anything but the thyroid. By the time it gets checked, people often have multiple years of symptoms.
The two main patterns
The thyroid runs your metabolic rate. When it's underactive (hypothyroidism), everything slows down. When it's overactive (hyperthyroidism), everything speeds up. The symptom patterns mirror each other:
Hypothyroid (slow) — feeling cold, weight gain, fatigue, depressed mood, constipation, dry skin, hair thinning (especially outer eyebrows), heavier or longer periods, slower heart rate, sleeping more, brain fog, brittle nails
Hyperthyroid (fast) — feeling hot, weight loss, heart palpitations, anxiety / restlessness, diarrhoea or loose stools, sweating more, lighter or absent periods, faster heart rate, difficulty falling asleep, tremor (shaky hands)
Symptoms that don't pick a side — fatigue, brain fog, muscle weakness, mood changes, neck swelling (goitre)
The pattern matters. A handful of symptoms all in the "slow" column points one direction. A handful all in the "fast" column points the other. A mix points either at non-thyroidal causes, at coexisting conditions, or at less common patterns.
Why women are over-represented
Hypothyroidism affects about 5% of US women and 0.5% of men — roughly 10× more common in women. Hyperthyroidism is less common overall (~1.2% lifetime risk) but still female-skewed. The mechanisms are largely autoimmune (Hashimoto's for hypo, Graves' for hyper), and autoimmune conditions in general affect women disproportionately.
The downside of this prevalence pattern is that thyroid symptoms in women are easy to attribute to other things — perimenopause, postpartum recovery, "just stress." That's why so many women spend years before getting a TSH check.
The single test that sorts most cases
TSH (thyroid-stimulating hormone) is the screening test. It works on a feedback loop: when the thyroid is underactive, the pituitary makes MORE TSH to try to stimulate it. When the thyroid is overactive, the pituitary makes LESS TSH because feedback is suppressing it.
Normal TSH range is roughly 0.4–4.0 mIU/L (varies by lab; some advocate a tighter upper bound around 2.5).
- TSH high → hypothyroidism likely (the body is trying to flog an underactive gland)
- TSH low → hyperthyroidism likely (feedback is suppressing the pituitary because the thyroid is overproducing)
- TSH normal → thyroid disease unlikely, with rare exceptions (central hypothyroidism is one)
If TSH is abnormal, the next step is usually free T4 (and sometimes free T3) to confirm the picture, plus anti-TPO antibodies if Hashimoto's is suspected.
Why "I had it tested 5 years ago" isn't enough
Thyroid disease can develop at any age. Hashimoto's frequently appears in the 30s–50s. Postpartum thyroiditis affects ~5% of women in the year after childbirth. Subclinical hypothyroidism (mildly elevated TSH with normal T4) often progresses over years. A TSH from 5 years ago is informative but doesn't rule out current thyroid disease.
If you have persistent symptoms that fit the pattern and your last TSH was years ago, asking for a recheck is reasonable and inexpensive.
The phrasing that works
> "I've had a number of symptoms over the past few months that could be thyroid-related — mostly in the [hypo / hyper / mixed] pattern. Could we check my TSH and free T4?"
That's a specific, actionable request. It anchors the visit and signals you've thought about it rather than just feeling vaguely bad.
Symptoms that are red flags regardless
A few specific findings warrant a thyroid check soon, not at the next routine visit:
- New visible neck swelling (goitre) or a discrete lump in the thyroid area
- Bulging eyes / eye changes (Graves' ophthalmopathy)
- Atrial fibrillation in someone otherwise healthy (especially under 60)
- Severe rapid weight loss with no other explanation
- Symptoms during or after pregnancy that don't resolve in the postpartum months
What about the "thyroid storm" / myxedema coma you've heard about?
These are rare extremes — thyroid storm is severe untreated hyperthyroidism with fever, tachycardia, agitation; myxedema coma is severe untreated hypothyroidism with hypothermia and altered mental status. Both are medical emergencies. Almost everyone reading this has the much more common and treatable presentations — the chronic, gradual, "I've been off for months" version.
Skip the symptom Googling
The Thyroid Symptom Checker tool lets you check the symptoms you actually have and shows the pattern at a glance — leans hypo, leans hyper, mixed, or few-symptoms. Snowflake icons mark hypo symptoms, flames mark hyper, so you can see the leaning while you check. Surfaces suggested phrasing for the visit. Same on-device privacy as the rest of /health.
The short version
The symptom pattern matters more than any single symptom. Hypo and hyper mirror each other in slow / fast directions. TSH is the screening test, it's cheap, and it sorts most cases. If you've got persistent symptoms that fit a pattern and your last test was years ago, it's worth asking for. The bar to ordering a TSH is low — most providers will agree readily once the question is posed.