Educational content only. This article does not constitute medical advice. Always consult a qualified healthcare professional for personal health decisions.
Thyroid-stimulating hormone (TSH) is produced by the pituitary gland and signals your thyroid to release T3 and T4 — the hormones that regulate metabolism, energy, temperature, and heart rate. TSH is the most sensitive early indicator of thyroid dysfunction.
An elevated TSH suggests the pituitary is working harder to stimulate an underactive thyroid (hypothyroidism). A low TSH suggests the thyroid is overactive and the pituitary is reducing its signal (hyperthyroidism). Symptoms of either condition can be subtle and develop gradually, making trend data especially valuable.
| Group | Low | Normal | High |
|---|---|---|---|
| Adults (general) | < 0.4 mIU/L | 0.4–4.0 mIU/L | > 4.0 mIU/L |
| Pregnancy (1st trimester) | — | 0.1–2.5 mIU/L | — |
| Adults > 60 years | — | 0.4–6.0 mIU/L (some labs) | — |
Note: TSH reference ranges vary significantly between laboratories and change during pregnancy. Use the reference range on your own report — and note that some endocrinologists treat to a tighter "optimal" range of 0.5–2.5 mIU/L.
Because TSH naturally varies by time of day and recent illness, a single reading is hard to interpret in isolation. Plotting 3+ readings taken at the same time of day over several months reveals whether your thyroid function is stable, shifting, or responding to treatment.
Upload any lab report and Kinmetry automatically extracts your TSH (Thyroid-Stimulating Hormone) readings and plots them over time — free plan available, no test kit required.
Get started free →This article is for educational purposes only and does not constitute medical advice, diagnosis, or treatment. Reference ranges are general guidelines — always use the values on your own laboratory report and consult your healthcare provider.