Version July 2025
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What is a follicle-stimulating hormone test? —
This is a test to measure the amount of follicle-stimulating hormone, or "FSH," in the blood. FSH is a hormone made by the pituitary gland. The pituitary gland is a small organ located just below the brain (figure 1).
FSH is involved in:
●Puberty – In teens, levels of FSH and other hormones normally rise as the body gets ready to go through puberty.
●The menstrual cycle (monthly periods) – After puberty, the level of FSH rises early in every cycle to make the ovary grow "follicles." These are the structures that contain eggs.
●Fertility – In females, normal amounts of FSH are needed to get pregnant. In males, a normal amount of FSH is needed for the testicles to make sperm.
Having too much or too little FSH can be a sign of a health problem.
Why might I get an FSH test? —
Your doctor might order this test:
●To learn more about early or late puberty – For example, if a child has signs of early puberty or if a teen has not gone through puberty at the expected time, an FSH test can give more information.
●To help figure out the cause of missed or irregular periods
●To check for causes of infertility – This is when a person has trouble getting pregnant or getting a partner pregnant. This can happen for different reasons. In females, an FSH test can tell doctors if the ovaries are working normally. In males, an FSH test and other tests can help the doctor figure out why a person has too few sperm.
●If you will be going through in vitro fertilization, or "IVF" – This is a procedure used to treat infertility. It involves using sperm to fertilize an egg in a lab, then putting the egg into the uterus to grow into a pregnancy. Doctors do an FSH test and other tests before IVF.
●If you have other symptoms suggesting problems with hormones
How do I prepare for an FSH test? —
For this test, you need to get a "blood draw." Your doctor or nurse will tell you where to go for this.
If you get periods, your doctor will schedule your FSH test early in your menstrual cycle. If you are not having periods, the test can be done on any day.
It might help to wear a short-sleeve shirt to your blood draw appointment. This makes it easier for the person drawing your blood to get to your arm.
What happens during a blood draw? —
A needle is used to take a small amount of blood from your arm (figure 2). Collecting the blood only takes a few minutes. The blood is then tested in a lab.
Tell the person who takes your blood:
●If you take "blood thinner" medicines or have a bleeding problem – They will make sure your bleeding is under control before you leave.
●If you have a latex allergy – Some of the supplies used for blood draws might contain latex.
●If you have a preferred arm to use
Most of the time, getting blood taken does not cause problems. You might have a little soreness or bruising where the needle went in.
What do my results mean? —
Your doctor or nurse will tell you when to expect your results, and will contact you with the results. Or if you use an online "patient portal," you might get an alert there when your results are ready.
If the test shows your FSH levels are too high or too low, your doctor or nurse will talk to you about what to do next. They might need to do more tests to figure out what the cause is.
If you do have a health problem, your doctor will work with you to come up with a plan for treatment.
Patient education: Early puberty (The Basics)
Patient education: Late puberty (The Basics)
Patient education: Absent or irregular periods (The Basics)
Patient education: Primary ovarian insufficiency (The Basics)
Patient education: Menopause (The Basics)
Patient education: Infertility in couples (The Basics)
Patient education: Female infertility (The Basics)
Patient education: Male infertility (The Basics)
Patient education: Absent or irregular periods (Beyond the Basics)
Patient education: Primary ovarian insufficiency (Beyond the Basics)
Patient education: Menopause (Beyond the Basics)
Patient education: Evaluation of infertility in couples (Beyond the Basics)
Patient education: In vitro fertilization (IVF) (Beyond the Basics)
