TSH: What It Means for Your Health
TSH is produced by the pituitary gland and signals the thyroid to produce thyroid hormones (T3 and T4). It is the single most important screening test for thyroid disorders. TSH works on a negative feedback loop: when thyroid hormones are low, TSH rises to stimulate the thyroid; when thyroid hormones are high, TSH drops. This inverse relationship makes TSH extremely sensitive to even subtle thyroid dysfunction.
Reference Range
Reference ranges may vary between laboratories, age groups, and sexes. The values shown are general adult reference ranges. Always compare your results to the specific range provided by your testing laboratory.
What Is TSH?
TSH is produced by the pituitary gland and signals the thyroid to produce thyroid hormones (T3 and T4). It is the single most important screening test for thyroid disorders. TSH works on a negative feedback loop: when thyroid hormones are low, TSH rises to stimulate the thyroid; when thyroid hormones are high, TSH drops. This inverse relationship makes TSH extremely sensitive to even subtle thyroid dysfunction.
Commonly included in:
What Does High TSH Mean?
Elevated TSH indicates the thyroid is underactive (hypothyroidism) — the pituitary is working harder to stimulate an underperforming thyroid. Causes include Hashimoto's thyroiditis (autoimmune), iodine deficiency, thyroid surgery, radiation, and certain medications (lithium, amiodarone). Symptoms include fatigue, weight gain, cold intolerance, constipation, dry skin, and depression.
What Does Low TSH Mean?
Low TSH indicates the thyroid is overactive (hyperthyroidism) — the pituitary suppresses TSH because thyroid hormones are already too high. Causes include Graves' disease (autoimmune), toxic nodular goiter, thyroiditis, or excessive thyroid medication. Symptoms include weight loss, rapid heartbeat, anxiety, tremor, heat intolerance, and insomnia.
Related Biomarkers in Thyroid Function
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This information is for educational purposes only and is not intended as medical advice, diagnosis, or treatment. Reference ranges may vary between laboratories. Always consult a qualified healthcare professional for interpretation of your blood test results and before making any health decisions.