Interpret Your Thyroid Stimulating Hormone Results
Enter your TSH value below and get an instant, free AI interpretation — a plain-English explanation checked against WHO/IFCC reference ranges.
Medical Disclaimer
This AI-generated interpretation is for educational purposes only and does not constitute medical advice, diagnosis, or treatment. Results may vary based on individual health factors not captured here.
Always consult a qualified healthcare professional before making any health decisions. Read full disclaimer →
Thyroid Stimulating Hormone Normal Ranges
TSH is secreted by the pituitary gland to control thyroid hormone production.
| Age Group | Sex | Reference Range | Unit | Notes |
|---|---|---|---|---|
| Adults (18–64) | All | 0.4 – 4 | mIU/L | — |
| Elderly (65+) | All | 0.5 – 6 | mIU/L | Higher range acceptable in elderly |
| All ages | Female | 0.1 – 2.5 | mIU/L | Pregnancy first trimester |
Also reported in: µIU/mL.
Critical (Panic) Values
Critical Low: < 0.01 mIU/L. Critical High: > 100 mIU/L. Values outside these limits require immediate clinical attention.
Why Doctors Order the Thyroid Stimulating Hormone Test
TSH is the best first-line test for thyroid disease because it is exquisitely sensitive — small changes in thyroid hormone levels cause much larger TSH changes (logarithmic relationship).
How to Enter Your TSH Result
Thyroid Stimulating Hormone can be reported in mIU/L or µIU/mL. Choose the unit printed next to your result on the lab report so it is compared with the matching reference range.
Reference ranges for TSH differ by age group, so entering your age gives a more accurate reading.
What a Low or High TSH Can Be Associated With
Below the reference range
- Graves' disease (most common cause of hyperthyroidism)
- Toxic multinodular goiter
- Solitary toxic thyroid nodule
- Excess levothyroxine therapy
- Subclinical hyperthyroidism (TSH low, FT4 normal)
Above the reference range
- Primary hypothyroidism (Hashimoto's thyroiditis, post-radioiodine, post-surgery)
- Subclinical hypothyroidism (TSH high, FT4 normal)
- Inadequate levothyroxine dose in treated hypothyroidism
- TSH-secreting pituitary adenoma (very rare)
- Recovery phase after non-thyroidal illness
This interpreter flags a result at or below 0.01 mIU/L or at or above 100 mIU/L as a critical value. Results that extreme are uncommon — contact your doctor promptly, and seek urgent medical care if you feel unwell.
These are common associations, not a diagnosis. A single result is read alongside your symptoms, history and other tests — discuss it with your doctor.
What Can Change Your TSH Result
Before you read too much into a result, consider whether any of these applied:
- Biotin supplements (high doses >10 mg/day interfere with many TSH assays, causing falsely low TSH)
- Non-thyroidal illness (sick euthyroid syndrome — TSH can be low or high during severe illness without true thyroid disease)
- Dopamine and corticosteroids (suppress TSH secretion)
- Pregnancy (first trimester lowers TSH due to hCG cross-reactivity with TSH receptors)
Preparing for the test: No fasting required. Ideally drawn in the morning — TSH has a slight diurnal variation (higher at night).
Symptoms That Often Prompt TSH Testing
- High TSH (hypothyroidism): fatigue, weight gain, cold intolerance, constipation, dry skin, hair loss, depression, brain fog, heavy periods
- Low TSH (hyperthyroidism): weight loss, heat intolerance, palpitations, anxiety, tremor, insomnia, diarrhea, exophthalmos (in Graves')
Want the full clinical guide to Thyroid Stimulating Hormone?
Reference ranges, causes, symptoms, preparation, and FAQs.