Symptoms suggest a thyroid change.
Arrange review for persistent tiredness, weight or temperature change, constipation, tremor, palpitations, neck swelling or menstrual changes.
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Thyroid concerns · GP care
Make sense of broad symptoms. Use the right blood tests.
Tiredness, weight change, temperature sensitivity, bowel or period changes, tremor and palpitations can have many causes. A GP can decide whether thyroid testing fits the pattern and interpret results in context.
Do not change levothyroxine or antithyroid medicine based on symptoms alone. Pregnancy and some supplements or medicines can change how results and doses should be managed.
Choose a suitable route
Choose the right starting point.
Gradual symptoms usually suit routine assessment, while severe cardiovascular or mental-state changes need urgent care.
A test or dose needs interpreting.
Review TSH and thyroid hormone results alongside symptoms, dose timing, missed tablets, pregnancy and medicines that affect absorption.
Book a results reviewSevere heart or mental-state symptoms.
Use urgent care for marked palpitations with illness, agitation or confusion; emergency care for chest pain, collapse or severe breathing difficulty.
Contact NHS 111Underactive and overactive thyroid symptoms overlap with menopause, anaemia, anxiety, depression, sleep problems and other conditions. Testing should follow the full history.
Notice the pattern
What changes the next step.
Opposite hormone changes can produce different patterns, but neither can be diagnosed from symptoms alone.
Underactive pattern
Tiredness, feeling cold, weight gain, constipation, dry skin, hair loss, low mood and heavy or irregular periods may occur.
Overactive pattern
Heat sensitivity, weight loss, tremor, anxiety, sweating, diarrhoea, poor sleep and a fast or irregular heartbeat may occur.
Neck and eye changes
A visible neck swelling or eye symptoms can add important information and may need examination.
Treatment-related pattern
Symptoms can return if doses are missed, absorption changes or the dose is too low or high, but blood tests are needed to guide changes.
Biotin supplements can interfere with some thyroid blood tests. Tell the clinician about supplements and follow laboratory instructions before testing.
A focused GP assessment
Use blood tests as part of the assessment, not in isolation.
A GP can review symptoms and examination findings, then interpret TSH and thyroid hormone results with the clinical context.
Explore in-person GP care01
Review the symptom cluster.
Discuss onset, weight, temperature tolerance, bowels, periods, mood, sleep, palpitations, neck swelling and family autoimmune history.
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Check medicines and timing.
Cover thyroid medicine dose and timing, missed tablets, supplements, antacids, iron, calcium, pregnancy and recent illness.
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Plan tests and follow-up.
TSH and T4 are commonly used; antibodies or other tests and specialist referral are considered when results or examination indicate.
A proportionate plan
Adjust treatment by results and clinical need.
Thyroid treatment is effective for many people, but safe dosing requires consistent use and scheduled monitoring.
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Underactive thyroid
Levothyroxine replaces thyroid hormone. Regular blood tests help find and maintain the appropriate dose.
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Overactive thyroid
Treatment may include medicine, radioactive iodine or surgery, usually with specialist input depending on cause and severity.
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Pregnancy planning
Tell your GP if you are pregnant or trying to conceive. Thyroid tests and medicine doses may need prompt review.
Take prescribed thyroid medicine consistently and check how to separate it from iron, calcium, antacids or food. Do not alter the dose without clinical advice.
Prepare for a useful review
Bring the actual results and how you take treatment.
Bring TSH, T4 and previous thyroid results with dates, plus the exact medicine dose, brand if relevant, timing and missed doses.
List supplements, iron, calcium, antacids and other medicines. Note pregnancy plans, recent illness, weight, pulse, neck or eye changes and family thyroid history.
Explore GP appointments ↗Good to know
Questions about thyroid health.
Practical answers to help you choose a sensible next step without trying to diagnose the concern yourself.
Which blood tests check the thyroid?
TSH and thyroxine, usually free T4, are common starting tests. The pattern and clinical context determine whether antibodies or other tests are useful.
Can I adjust levothyroxine if I feel tired?
No. Tiredness has many causes, and too much or too little thyroid hormone can both cause harm. Review symptoms and blood tests with a clinician.
Does pregnancy affect thyroid treatment?
Yes. If you are pregnant or planning pregnancy, tell your GP promptly because testing and levothyroxine dose may need to change.
Can supplements affect thyroid tests?
Yes. Biotin can interfere with some tests, and iron, calcium or antacids can affect levothyroxine absorption. Share all supplements and follow professional instructions.
Clinical information: NHS underactive thyroidNHS overactive thyroidNHS levothyroxine. This information is general and does not replace individual medical advice.