TSH – The thyroid-stimulating hormone

What is TSH?

TSH (thyroid-stimulating hormone) is produced in the pituitary gland and signals the thyroid to produce the hormones T4 and T3. The pituitary gland increases TSH when the thyroid produces too little and lowers it when it produces too much.

Why is TSH measured in a health check?

Thyroid disorders are common, especially in women, and cause vague symptoms such as fatigue, cold intolerance, weight changes, hair loss, palpitations, or low mood. TSH is the most sensitive single test for catching them.

High and low values

High value: High TSH indicates an underactive thyroid (hypothyroidism), where the body receives too little thyroid hormone.

Low value: Low TSH indicates an overactive thyroid (hyperthyroidism) with too much thyroid hormone in circulation.

Reference ranges differ between laboratories, sexes and ages and are stated in your result. The information here does not replace medical assessment.

How TSH is measured in a health check

TSH is analysed from a standard blood test and requires no fasting. The level varies over the course of the day, being highest during the night and early morning, then falling during the day. This difference rarely matters for an initial screening, but if you're comparing several tests over time it's best to take them at roughly the same time of day.

High doses of biotin in dietary supplements can interfere with the analysis and give inaccurate thyroid results. If you use hair vitamins or a high-dose B-vitamin complex, the recommendation is usually to pause for a day or so before the test and mention it when the result is interpreted.

Symptoms that make thyroid testing relevant

Thyroid disorders cause vague symptoms that are easily mistaken for stress, iron deficiency or lack of sleep. This is one reason TSH is included in so many health checks — the symptom picture alone is rarely enough to distinguish the conditions.

• Underactivity: fatigue, feeling cold, dry skin, constipation, weight gain, low mood, hair loss
• Overactivity: palpitations, sweating, anxiety, sleep problems, weight loss, tremor
• Shared: difficulty concentrating, irregular periods and reduced stamina

TSH alongside T4, T3 and antibodies

TSH is sensitive because the pituitary gland reacts early to small changes in thyroid hormone. An abnormal TSH is therefore supplemented with free T4 and sometimes free T3 to see how much hormone the gland is actually producing. High TSH combined with low free T4 suggests hypothyroidism, while low TSH and high free T4 suggests hyperthyroidism.

If autoimmune thyroid disease is suspected, TPO antibodies may be analysed. A slightly abnormal TSH without symptoms is usually rechecked after a few weeks before conclusions are drawn, since infections, stress and temporary fluctuations can affect the value.

How often should TSH be checked?

For adults without symptoms, a check as part of a health check every other year is usually enough. Women over 40, people with autoimmune disease in the family, and those planning pregnancy have reason to check more often. If you're being treated with levothyroxine, your care provider determines the testing interval, usually every six to twelve months once the dose is stable.

Frequently asked questions about TSH

Health checks that include TSH

TSH is included in 11 of Labkollen's health checks. Analysis name in the result: TSH.

• Man +

  49 markers

  Labkollens mest omfattande kontroll för män – inklusive testosteron, PSA och hjärt-kärlmarkörer.

  2 195 krMed prenumeration (årlig hälsokontroll): 1 756 kr

  See the test

• Kvinna +

  44 markers

  Labkollens mest omfattande kontroll för kvinnor – inklusive järnstatus, sköldkörtel och hormoner.

  2 195 krMed prenumeration (årlig hälsokontroll): 1 756 kr

  See the test

• Standard

  37 markers

  Bred hälsokontroll över blodsocker, blodfetter, blodvärde, lever, njurar, sköldkörtel och vitaminer.

  1 895 krMed prenumeration (årlig hälsokontroll): 1 516 kr

  See the test

• Seniorkollen

  32 markers

  Anpassad kontroll för dig över 65 med fokus på hjärta, njurar, sköldkörtel och näringsstatus.

  1 399 krMed prenumeration (årlig hälsokontroll): 1 119 kr

  See the test

• Gravid

  26 markers

  Kontroll under graviditet – blodvärde, järn, sköldkörtel, vitaminer och hCG.

  1 199 krMed prenumeration (årlig hälsokontroll): 959 kr

  See the test

• Uthållighetssport

  16 markers

  För löpare, cyklister och simmare – järnstatus, energiomsättning och återhämtning.

  1 599 krMed prenumeration (årlig hälsokontroll): 1 279 kr

  See the test

• Lagsport

  16 markers

  För lagidrottare – energi, järn, återhämtning och stresshormon.

  1 599 krMed prenumeration (årlig hälsokontroll): 1 279 kr

  See the test

• Styrkesport

  15 markers

  För styrketräning – hormoner, muskelmarkörer, lever och mineraler.

  1 599 krMed prenumeration (årlig hälsokontroll): 1 279 kr

  See the test

• Kampsport

  15 markers

  För kampsportare – återhämtning, hormoner, inflammation och järn.

  1 599 krMed prenumeration (årlig hälsokontroll): 1 279 kr

  See the test

• Gymnastik och konståkning

  14 markers

  För teknikidrotter – benhälsa, järnstatus, sköldkörtel och tillväxtmarkörer.

  1 599 krMed prenumeration (årlig hälsokontroll): 1 279 kr

  See the test

• Fertilitet

  8 markers

  Hormonmarkörer kopplade till fertilitet, inklusive AMH och sköldkörtel.

  1 599 krMed prenumeration (årlig hälsokontroll): 1 279 kr

  See the test

Unsure which test you need? Start the test guide

Guides covering TSH

• Trött hela tiden? Det här visar ett blodprov
• Hälsokontroll för kvinnor – vilka prover?
• Hälsokontroll efter 40 – vad bör ingå?
• Hälsokontroll efter 50 – vad bör ingå?
• Hälsokontroll efter 60 – vad bör ingå?
• Hälsokontroll för företag och anställda
• Hälsokontroll för dig som tränar mycket