Inhibin B is a hormone produced primarily by the testes in males and the ovaries in females. It plays a crucial role in regulating the production of follicle-stimulating hormone (FSH) from the pituitary gland. By inhibiting FSH secretion, inhibin B helps maintain the balance of reproductive hormones in the body. In males, inhibin B is important for sperm production and overall fertility. In females, it is involved in the menstrual cycle and ovarian function. Measuring inhibin B levels can provide valuable information about reproductive health and is often used in fertility assessments.