Follicle-stimulating hormone, more commonly referred to as FSH, is a hormone which is both produced and released into the body by the pituitary gland. Located in the base of the brain, the pituitary gland is primarily responsible for producing and secreting various hormones which control growth and sexual development. FSH is related to sexual development and functioning in both men and women; therefore, low FSH levels may result in a variety of reproductive conditions. FSH levels may be affected as a result of issues ranging from stress and being underweight to tumors or other abnormalities that prevent the pituitary gland from functioning properly.
One of the most common effects of low FSH levels in the body is decreased levels of reproductive cells, which may contribute to infertility if left untreated. In women, this may result in decreased amounts of eggs that are produced by the ovaries. Men who do not have adequate amounts of FSH will generally have a reduced sperm count.
Abnormally low amounts of FSH hormones in the body may also affect the physical development of reproductive organs, a condition known as hypogonadism. In males, one of the primary functions of the hormone is to stimulate the growth of the testicles. If an insufficient amount of FSH is present in the body during puberty, it may result in a male having underdeveloped testicles along with decreased functioning of the sperm. Hypogonadism may also occur after puberty and cause loss of body and facial hair, breast growth, muscle loss, and difficulty with sexual functioning.
Females who have low amounts of the FSH hormone during puberty may not begin menstruating or developing breasts. If the condition occurs after puberty, a woman may notice a loss in body hair and a decreased level of sexual interest. Low FSH levels in adulthood also tend to result in a stop in menstrual periods. If female hypogonadism is left untreated, it may lead to early menopause.
If a person is experiencing issues with sexual development or functioning, a blood sample is usually taken and tested to determine if there are abnormal amounts of the FSH hormone in the body. To prevent permanent complications from low FSH levels, a doctor will typically recommend a patient take a synthetic version of the hormone to help regulate it to a normal level. Inadequate amounts of the hormone may also be one of the symptoms of conditions, such as polycystic ovary disease, Klinefelter syndrome, Turner syndrome, or anorexia. Testing for FSH is often used as a tool to diagnose these conditions and determine the best treatment options.