What is FSH?
FSH (follicle-stimulating hormone) is made by the pituitary gland. In women who have periods, it helps control the menstrual cycle and triggers eggs to grow in the ovaries, getting them ready for ovulation. In men, it helps control how much sperm the testicles make and how healthy the sperm are.
FSH works as a signal, so its level tells you how hard the pituitary is pushing. When the ovaries or testicles stop making enough sex hormones, the pituitary makes more FSH to try to get them working, and FSH climbs. That is why a high FSH is a hallmark of menopause. FSH is almost always read with LH and estradiol (or testosterone in men).
FSH normal range
| Group | FSH (IU/L = mIU/mL) | Source |
|---|---|---|
| Women, follicular phase | 3.5 to 12.5 | ARUP |
| Women, mid-cycle | 4.7 to 21.5 | ARUP |
| Women, luteal phase | 1.7 to 7.7 | ARUP |
| Women, postmenopausal | 25.8 to 134.8 | ARUP, MedlinePlus |
| Women still menstruating | 4.7 to 21.5 | MedlinePlus |
| Men, adult | 1.5 to 12.4 | ARUP, MedlinePlus |
ARUP Laboratories reference intervals.
Children have low FSH until puberty, when it starts to rise. Ranges vary between labs and assays, so always use the range on your report.
What high FSH means
MedlinePlus lists these conditions linked to high FSH:
- Women: menopause or perimenopause (including early menopause), primary ovarian insufficiency, ovaries that never developed normally, polycystic ovary syndrome (PCOS), an ovarian tumor, thyroid or adrenal disorders, and Turner syndrome
- Men: damage to the testicles from alcohol overuse, chemotherapy, radiation, mumps or injury, a germ cell tumor, and Klinefelter syndrome
- Both: autoimmune damage to the ovaries or testicles, hormone treatment, and certain pituitary tumors
In women 45 and older, high FSH and LH often mean menopause is approaching. A high FSH in a younger woman with missed periods, or in a man with low testosterone or fertility problems, needs a doctor's workup.
FSH in men
In men, FSH mainly reflects sperm production. A high FSH with low testosterone points to a problem in the testicles themselves, because the pituitary is pushing harder to get a response. A low or normal FSH and LH with low testosterone points to the pituitary or hypothalamus instead. That distinction changes which tests come next, so it is worth asking your doctor about FSH and LH if your testosterone comes back low.
Worked example: high FSH with low testosterone
Say a 36-year-old man who has been trying to conceive with his partner gets an FSH of 18 IU/L and a total testosterone of 260 ng/dL on two morning tests. FSH is above ARUP's 1.5 to 12.4 IU/L range for adult men, and testosterone is under the AUA's 300 ng/dL cut-off.
High FSH with low testosterone points to the testicles rather than the pituitary: the brain is pushing harder and getting little response. MedlinePlus lists alcohol overuse, chemotherapy, radiation, mumps, injury, a germ cell tumor and Klinefelter syndrome among the causes.
Questions for the doctor: Should we check LH too? Should I be referred to a urologist or fertility specialist? Should testosterone therapy wait while we try to conceive? The Endocrine Society recommends against starting it in men planning fertility soon.
What low FSH means
A low FSH usually means the signal from the brain is weak. MedlinePlus links it to the pituitary gland or hypothalamus not making normal amounts of hormones, and in women to being very underweight or recent rapid weight loss, not ovulating, and pregnancy. In women with missed periods, low LH and FSH may also be linked with extreme exercise, malnutrition or stress.
What can change FSH
- Cycle day. FSH moves through the cycle, so women who have periods may be asked to test on a specific day.
- Age. FSH rises through perimenopause and stays high after menopause.
- Hormone treatment. Hormone therapy can raise FSH, and birth control, testosterone and DHEA affect LH, FSH's partner hormone (MedlinePlus). Tell whoever orders the test what you take.
- Weight and training. Very low body weight, rapid weight loss and extreme exercise can suppress FSH in women.
How to test FSH
- If you have periods, test on the cycle day your doctor asks for and record it.
- Test FSH with LH and estradiol, not on its own.
- Expect your doctor to repeat an unexpected result before drawing conclusions.
Home urine FSH tests
Pharmacy urine FSH kits can help show whether menopause or perimenopause might explain symptoms such as irregular periods or hot flashes. MedlinePlus notes they can only detect higher than normal FSH and should not be used to judge whether you can get pregnant. A blood test gives an actual number you can track.
Common questions about FSH
Can FSH tell me if I am in menopause?
MedlinePlus says high FSH is a normal sign of perimenopause and menopause: as the ovaries release fewer eggs, the body makes more FSH to try to trigger ovulation. Doctors still weigh missed periods and symptoms rather than FSH alone. Our perimenopause blood test guide covers the full set.
What is tested with FSH?
MedlinePlus says FSH is often tested with LH, and estrogen, testosterone and progesterone tests are commonly done alongside it. It is also used to help find the cause of infertility in women and men.
Why would a child have an FSH test?
MedlinePlus says FSH testing in children is most often used to find out whether a medical disorder is causing early or late puberty.
Which at-home tests include FSH
SiPhox Health measures FSH in blood on three panels:
- Longevity Essentials (default panel, women only): FSH, LH, the LH:FSH ratio and sensitive estradiol, plus heart, metabolic and thyroid markers.
- Hormone Focus (men and women): FSH, LH and the ratio, with progesterone, prolactin, testosterone, SHBG and DHEA-S.
- Ultimate 360 (+$125 a test): all of the above.
Men need Hormone Focus or Ultimate 360 for FSH. Women approaching menopause can track FSH and estradiol on Longevity Essentials each cycle at no extra cost. See our at-home hormone test guide for women or the SiPhox review.
A note on home samples: SiPhox's partner lab tests capillary blood collected from the upper arm. SiPhox says its results show a 95% to 99% correlation with venous draws in its own quarterly comparisons against Labcorp and Quest, but it has not published a study of the EasyDraw device. If a result would change a treatment decision, confirm it with a venous test through your doctor.
Longevity Essentials
The default panel: heart, metabolic, hormone and inflammation markers in one draw.
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Hormone Focus
Sex hormones for men and women, including PSA for men and progesterone for women.
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Ultimate 360
Everything on the four core panels plus iron studies, B12 and folate, GGT and PSA.
Check priceFrequently asked questions
What is a normal FSH level for a woman?
It depends on the phase: 3.5 to 12.5 IU/L follicular, 4.7 to 21.5 mid-cycle and 1.7 to 7.7 luteal on ARUP's ranges. After menopause it is 25.8 to 134.8 IU/L.
What FSH level indicates menopause?
Postmenopausal FSH is 25.8 to 134.8 IU/L on the ARUP and MedlinePlus ranges. Doctors look at missed periods and symptoms too, not FSH alone.
What is a normal FSH level for a man?
About 1.5 to 12.4 IU/L for adult men. High FSH in a man can point to testicular damage; low FSH points to the pituitary or hypothalamus.
Are mIU/mL and IU/L the same for FSH?
Yes. 1 mIU/mL equals 1 IU/L, so the number is identical in either unit.
Sources
- ARUP Laboratories Test Directory: Luteinizing hormone and follicle stimulating hormone
- MedlinePlus Medical Encyclopedia: Follicle-stimulating hormone (FSH) blood test
- MedlinePlus Lab Tests: Follicle-stimulating hormone (FSH) levels test
- MedlinePlus Lab Tests: Luteinizing hormone (LH) levels test
- American Urological Association: Evaluation and management of testosterone deficiency guideline
- Bhasin S et al. Testosterone therapy in men with hypogonadism: an Endocrine Society clinical practice guideline. J Clin Endocrinol Metab 2018
- SiPhox Health: panel comparison (checked 29 Sep 2026)
- SiPhox Health: Longevity Essentials panel
- SiPhox Health: Hormone Focus panel