LH levels: normal range for women and men

What is LH?

LH (luteinizing hormone) is made by the pituitary gland. In women who have periods, it helps control the menstrual cycle, and a sharp rise just before ovulation triggers the release of an egg. In men, LH tells the testicles to make testosterone, which is needed to make sperm; in men it normally does not change much.

LH is usually read with FSH, the other pituitary hormone that controls the ovaries and testicles, and with the hormone they control: estradiol in women and testosterone in men. The combination shows where a problem sits. When the ovaries or testicles fail, LH and FSH rise; when the pituitary or hypothalamus is the problem, they are low.

LH normal range

LH is normally low in early childhood and starts to rise slowly in the years before puberty, usually between ages six and eight. Labs differ, so use the range on your own report. Note how far apart the phases are: the top of the follicular range is 12.6 IU/L, while the surge can reach 95.6 IU/L, so an LH result without a cycle day is very hard to read.

Check LH, FSH and estradiol togetherLongevity Essentials includes LH, FSH, the LH:FSH ratio and sensitive estradiol for women, $124 a test plus $25 shipping.

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What high LH means

In women, a rise about two weeks after your period usually means you are ovulating normally. LH that stays high through the month is different. MedlinePlus links it to:

• Not ovulating
• Polycystic ovary syndrome (PCOS), an imbalance of female sex hormones
• Menopause, or approaching it (women 45 and older)
• Primary ovarian insufficiency or ovaries that make little or no hormone
• Thyroid or adrenal disorders, and Turner syndrome

In men, high LH usually means the testicles are not responding, so the pituitary is pushing harder. Causes include testicles that do not work or never developed normally, a germ cell tumor, mumps, injury, Klinefelter syndrome, and damage from chemotherapy, radiation or autoimmune disease.

LH and FSH in PCOS

MedlinePlus lists PCOS among the causes of high LH, and many labs, including SiPhox, report an LH:FSH ratio. No single blood test diagnoses PCOS: MedlinePlus notes that hormone tests such as SHBG help only when paired with other results, including androgen levels such as free testosterone.

Worked example: LH well above FSH

Say a 24-year-old woman whose periods come every 45 to 60 days gets an LH of 16 IU/L and an FSH of 6 IU/L on cycle day 4, an LH:FSH ratio of about 2.7. Her LH is above ARUP's follicular range of 2.4 to 12.6 IU/L, while her FSH sits inside the follicular range of 3.5 to 12.5 IU/L.

LH that is high outside the mid-cycle surge is on MedlinePlus's list for PCOS and for not ovulating. No single blood test diagnoses PCOS, though, and MedlinePlus lists thyroid disorders among the causes of high LH as well.

Questions for the doctor: Do my cycles and these numbers justify a PCOS workup? Should we check free testosterone, SHBG, prolactin and TSH? Our PCOS blood test guide lists the markers usually involved.

What low LH means

Low LH in adults is often a sign of a problem with the pituitary gland or hypothalamus, which then under-drives the ovaries or testicles. In women with missed periods, low LH and FSH may be linked to extreme exercise, malnutrition, stress or being very underweight. In men, low testosterone with a low or normal LH suggests the problem is in the brain's signaling rather than the testicles.

What can change LH

• Cycle day. The surge lasts a short time, so a single test can miss it or catch it.
• Medicines and supplements. MedlinePlus lists birth control pills, hormone therapy, testosterone and DHEA. Do not stop anything without your doctor.
• Recent nuclear medicine scans (radioisotopes) can interfere with some LH tests.
• Weight, training and stress can suppress LH in women.

How to test LH

• If you have periods, test on the day your doctor specifies and record your cycle day.
• For fertility timing, urine ovulation tests detect the LH surge at home and are designed for that job.
• Men can test at any point in the month, but should test in the morning if testosterone is drawn at the same time.

Common questions about LH

Blood LH or a urine ovulation test?

MedlinePlus says at-home tests that measure LH in urine are usually used to track ovulation, because LH rises quickly just before an egg is released. A blood LH is better for reading the overall pattern with FSH and estradiol, for example with irregular periods or low testosterone.

Do I need to stop any medicines first?

Possibly. MedlinePlus says you may need to stop certain medicines or supplements before the test and lists birth control pills, hormone therapy, testosterone and DHEA as things that affect LH. Only stop something if your doctor tells you to.

When does LH start to rise in children?

Slowly in the years before puberty, usually between ages six and eight (MedlinePlus), so a child's result is read against pediatric ranges.

Which at-home tests include LH

SiPhox Health measures LH in blood on three panels. Longevity Essentials includes LH, FSH, the LH:FSH ratio and sensitive estradiol for women only. Hormone Focus includes LH for men and women, with FSH, the ratio, testosterone, SHBG, progesterone and prolactin. Ultimate 360 includes all of them. Men need Hormone Focus or Ultimate 360 for LH.

A blood kit is not an ovulation predictor: use urine LH strips to time ovulation, and a blood panel to look at your overall hormone pattern. Compare options in our at-home hormone test guide for women or, for men, the at-home testosterone test guide.

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.

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