SIGNAL // LOADING
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Glossary term
TSH
Also known as Thyroid-stimulating hormone - Thyrotropin
The pituitary's thyroid signal. Lab normal tops out at 4.5 mIU/L - functional targets run under 2.5.
Thyroid-stimulating hormone is the pituitary's message to the thyroid to make more or less hormone. TSH above 4.0-4.5 mIU/L flags hypothyroidism on most reference ranges, but symptom data and integrative endocrinology suggest a tighter functional target of 0.5-2.5 mIU/L. TSH alone misses conversion problems - a normal TSH with low free T3 is a common missed pattern in fatigue and weight-stall cases. Always pair with free T3, free T4, and thyroid antibodies (anti-TPO, anti-TG) to rule out Hashimoto's. Included on the Advanced panel.
- Symbol
- TSH
- Unit
- mIU/L
- Typical range
- Standard lab range ~0.4-4.5 mIU/L; functional target often 0.5-2.5 mIU/L.
Medically reviewed byDr. Lena Okafor, MD
Medical Director - updated April 2026How we review
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