Follicle-Stimulating Hormone

Does this test have other names?

FSH

What is this test?

This test measures the level of follicle-stimulating hormone (FSH). FSH is an important hormone made in your pituitary gland.

Hormones are chemical messengers that travel through your blood. Your pituitary gland is located on the underside of your brain. FSH is made in the front part of your pituitary gland.

If you are a man, FSH travels to your testicles. There, it tells the cells in your testicles to make sperm. If you are a woman, FSH travels to your ovaries. There, it stimulate the growth of eggs during your menstrual cycle. In children, FSH is important for sexual development.

Why do I need this test?

You may need this test to find out if your pituitary gland is making too much or too little FSH. This test can help your healthcare provider tell if problems you may be having are caused by your pituitary gland or by your ovaries or testicles. Some conditions that may be checked with this test include:

• Ovarian failure in women

• Testicular failure in men

• Early or late puberty in children

• Fertility problems in men and women

What other tests might I have along with this test?

You may also need a blood test that measures another pituitary hormone called luteinizing hormone (LH). LH is also important for normal function of your testicles or ovaries. You may also have tests to measure other hormone levels.

What do my test results mean?

Test results may vary depending on your age, gender, health history, the method used for the test, and other things. Your test results may not mean you have a problem. Ask your healthcare provider what your test results mean for you.

FSH is measured in international units per milliliter (IU/mL). Normal results of this test for men are:

• 1.4 to 15.5 IU/mL

If you are a woman, the normal results depend on where you are in your menstrual cycle. Your healthcare provider will help you understand the results. Normal results are:

• 1.4 to 9.9 IU/mL (follicular phase)

• 6.2 to 17.2  IU/mL (ovulatory peak)

• 1.1 to 9.2 IU/mL (luteal phase)

• 19 to 100 IU/mL after menopause

If this test is done for your child, a normal result will depend on how the test was done and what units of measurement were used.

Many conditions can cause your FSH to be too high or too low. Your healthcare provider will talk with you about the results of your blood test, and whether you need more testing.

How is this test done?

The test is done with a blood sample. A needle is used to draw blood from a vein in your arm or hand. 

Does this test pose any risks?

Having a blood test with a needle carries some risks. These include bleeding, infection, bruising, and feeling lightheaded. When the needle pricks your arm or hand, you may feel a slight sting or pain. Afterward, the site may be sore.

What might affect my test results?

Being pregnant or taking birth control pills may affect the results of this test. Some medicines may also affect the results.

How do I get ready for this test?

You don't need to prepare for this test. But be sure your healthcare provider knows about all medicines, herbs, vitamins, and supplements you are taking. This includes medicines that don't need a prescription and any illegal drugs you may use.