TSH (Thyroid-Stimulating Hormone)
Also Known As: TSH, Thyrotropin, Thyrotropic Hormone
Thyroid-stimulating hormone (TSH) signals the thyroid gland to make hormones that control how your body uses and stores energy, called metabolism. Testing the TSH level in your blood can reveal if your thyroid gland is functioning normally.
The TSH level is tightly controlled by the levels of other thyroid hormones in your blood. Hypothyroidism — high TSH levels — may indicate your thyroid is underactive and needs more stimulation. Low levels, or hyperthyroidism, may mean it’s overactive and needs less stimulation. About 5% of American adults have hypothyroidism, and slightly more than 1% have hyperthyroidism.