Follicle-stimulating hormone (FSH) levels test measures the level of follicle-stimulating hormone (FSH) in your blood.
In women, FSH helps control the menstrual cycle and stimulates the growth of eggs in the ovaries.
In men, FSH helps control the production of sperm. Normally, FSH levels in men do not change very much. Too much or too little FSH can cause a variety of problems, including infertility, menstrual difficulties in women, and low sex drive in men.