Health topic · Hormones
Underactive thyroid (hypothyroidism)
Hypothyroidism means the thyroid gland does not make enough hormone. Learn the common symptoms, how TSH testing is used and why it is often missed.
Written by LON6EVITY Editorial Team · Last updated
Overview
NIDDK describes hypothyroidism as a condition in which the thyroid gland does not make enough thyroid hormone, slowing many of the body's functions.
Symptoms
The NHS lists tiredness, weight gain, feeling cold and low mood among possible symptoms. They develop slowly and overlap with many other conditions, so they are easy to miss.
Testing
A blood test for TSH is usually the first step, often with free T4. A single abnormal result is typically repeated before a diagnosis is made.
Treatment
When confirmed, it is usually treated with thyroid hormone replacement and monitored with regular blood tests, as described by the NHS.
Factors that can affect the result
- Autoimmune thyroid disease
- Previous thyroid treatment
- Some medicines
- Pregnancy
Questions people commonly ask
- Is a slightly high TSH always hypothyroidism?
- No. Mild changes can be temporary; clinicians usually repeat the test.
Related biomarkers
Related tests
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