Thyrotropin-releasing hormone, also called thyrotropin-releasing factor (TRF), thyroliberin, or protirelin, is a tripeptide hormone that stimulates the release of thyroid-stimulating hormone (TSH) and prolactin by the anterior pituitary gland. Thyroid-releasing hormone (TRH) is produced by the hypothalamus, near the paraventricular nucleus, and travels across the median eminence to the pituitary via the pituitary portal system.

The release of TRH depends on a number of factors, inclduing the levels of TSH, glucose, and thyroxine in the blood and the rate of metabolism in the body.