Thyroid-Stimulating Hormone (TSH)
Quick answer
What is Thyroid-Stimulating Hormone (TSH)?
TSH is the pituitary signal that drives thyroid hormone production. It's the first-line thyroid screen. High TSH suggests an underactive thyroid (hypothyroidism); low TSH suggests an overactive thyroid (hyperthyroidism). Both impact testosterone, SHBG, energy, and metabolism.
- Units:
- mIU/L
- Reference range:
- 0.4-4.0 mIU/L
- Sample:
- Venous blood (serum)
- Category
- Thyroid
- Units
- mIU/L
- Reference range
- 0.4-4.0 mIU/L
What does a high Thyroid-Stimulating Hormone result mean?
Hypothyroidism (Hashimoto's most common). Subclinical at TSH 4-10, overt above 10.
What does a low Thyroid-Stimulating Hormone result mean?
Hyperthyroidism (Graves' most common), excess thyroid replacement, transient thyroiditis.
Why does Thyroid-Stimulating Hormone matter?
Untreated thyroid dysfunction looks identical to low T in many men. Always include TSH on a hormone panel.
FAQs
- Is TSH alone enough to assess thyroid?
- For screening, usually yes. If TSH is abnormal or symptoms are strong despite normal TSH, add free T4, free T3, and thyroid antibodies (TPO, TG).
References
- [1]Thyroid Function Tests: Interpretation and Clinical UseNCBI Bookshelf / Endotext
- [2]Clinical Methods: The History, Physical, and Laboratory ExaminationsNCBI Bookshelf
Want Thyroid-Stimulating Hormone interpreted in the context of your full panel? Every FORM bloodwork tier covers it, with an MD walking you through the result.
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