Gonadotropin-Releasing Hormone Unit Converter

Gonadotropin-releasing hormone (GnRH) is a small signaling hormone produced by specialized nerve cells in the hypothalamus. It acts as the master switch for the reproductive hormone cascade, telling the pituitary gland to produce follicle-stimulating hormone (FSH) and luteinizing hormone (LH).

GnRH is released in pulses rather than continuously. In women, pulse frequency varies across the menstrual cycle (roughly every 1–2 hours during the follicular phase and every 4 hours during the luteal phase). In men, pulses occur approximately every 2 hours.

Because GnRH has a very short half-life (2–4 minutes) and circulates mainly within the tiny portal blood vessels between the hypothalamus and pituitary, it cannot be reliably measured in a standard blood draw. Instead, clinicians assess GnRH function indirectly by measuring LH and FSH, or by using a GnRH stimulation test.

GnRH is produced by approximately 1,000–1,500 specialized neurons in the hypothalamus, primarily in the medial preoptic area and the arcuate nucleus. It is released into the hypothalamic-hypophyseal portal blood vessels that connect the hypothalamus directly to the pituitary gland.