Hormones · Blood

LH

Pituitary hormone that triggers ovulation and, in men, drives testosterone production; assessed together with FSH.

At a glance

Measured in blood
In 9 test panels
Check the preparation

Explanation

LH: what is measured?

LH (luteinizing hormone) comes from the pituitary gland. In women it rises sharply for a short time halfway through the cycle, which triggers ovulation; after that it drives the production of progesterone. In men, LH prompts the testicles to make testosterone. Like FSH, LH rises when the sex glands work less well and falls when the control from the brain falters.

What can it detect?

The cause of low testosterone in men: a high LH points to the testicles, a low LH to the pituitary gland or to suppression by anabolic steroids
Polycystic ovary syndrome (PCOS): LH is often raised relative to FSH
Disturbed control when periods stop: underweight, stress, intensive sport, a pituitary condition
Failure of the ovaries or testicles (together with FSH)

Result

What does the result mean?

LH too high

In women, a high value around ovulation is normal; outside those days, a raised LH fits PCOS, often with an irregular cycle, acne and excess hair growth, or reduced function of the ovaries, as in menopause. In men, a raised LH with a low testosterone indicates that the testicles themselves make less, for example after a mumps infection, chemotherapy, radiotherapy or in Klinefelter syndrome. A raised LH with a normal testosterone can be an early sign of reduced testicular function at an older age.

LH too low

A low LH is normal when using the pill, during pregnancy and breastfeeding, and before puberty. In men with a low testosterone, a low or low-normal LH points to a cause in the pituitary gland or hypothalamus, or to suppression by anabolic steroids, testosterone treatment or opioids; after stopping steroids, recovery can take months. In women whose periods have stopped, a low LH fits underweight, an eating disorder, intensive training, stress or a pituitary condition. A low value on its own, without symptoms and without the other hormones, says little.

After an abnormal result

The GP assesses LH together with FSH, estradiol or testosterone and the day of the cycle, and usually repeats an abnormal value after a few weeks. With suspected PCOS, an ultrasound often follows; with a pituitary cause or a condition of the testicles, a referral to a gynecologist, urologist or internist-endocrinologist.

Reliability

How reliable is the test?

LH is virtually never assessed on its own, but together with FSH and estradiol or testosterone; it then helps to locate the cause of an abnormality. According to the Dutch Society for Clinical Chemistry (NVKC), LH is unsuitable for establishing menopause (FSH says more there), and during menopause the hormone values vary too much to establish menopause with a blood test. For the diagnosis of PCOS, a raised LH/FSH ratio is not a criterion: the diagnosis is based on the cycle, signs of too much male hormone and an ultrasound.

What can affect the result?

In women, the day of the cycle determines the result: the standard blood draw is on day 2 to 5; around ovulation LH is many times higher for a short time.
The pill, hormone therapy, pregnancy and breastfeeding suppress LH.
Anabolic steroids, testosterone, opioids and severe illness or malnutrition lower LH; biotin supplements can interfere with the measurement.
LH is released in pulses, so two measurements on the same day can differ.

Preparation

Do you have a menstrual cycle? Then have your blood taken on day 2 to 5 of your cycle (day 1 is the first day of your period). Without a cycle, on the pill or after menopause the day does not matter.
Do you take biotin (vitamin B8, often in hair and nail supplements)? Stop at least 2 days before the sample is taken, or 4 days for a high dose.

Who it is for

Who is the test useful for?

Useful for

Useful together with FSH in men with a repeatedly low testosterone to locate the cause, after stopping anabolic steroids to monitor recovery, and in women with absent or irregular periods or suspected PCOS. Not useful for establishing menopause and not as a stand-alone test when trying to conceive. When using the pill, the result cannot be interpreted.

How common is it?

PCOS occurs in about 5 to 10 in 100 women of childbearing age and is the most common cause of an irregular cycle. A testosterone deficiency due to the testicles or the pituitary gland is estimated to occur in a few percent of men over 40; suppression by anabolic steroids is a common, usually temporary cause of a low LH in strength athletes.

The Dutch GP guideline (NHG) on amenorrhea and the NVE guidance on hypogonadism in adult men

Drawbacks and risks

Without the day of the cycle, a normal peak around ovulation can be read as 'too high'; a raised LH does not prove PCOS.

Get tested

LH: test panels

LH is part of these test panels. You order online and have your blood drawn at a collection point or collect the sample at home.

Blood draw
Luteinizing Hormone (LH)
LH as a marker for pituitary function and fertility.
€ 32,00
Blood draw
Bodybuilder Test
Panel for strength and muscle development; hormones, liver, and muscles.
€ 134,00
Fingerstick
Luteinizing Hormone (LH)
LH for ovulation and testicular function; also for sports or TRT monitoring.
€ 32,00
Blood draw
Testosterone Replacement Therapy (TRT)
Testosterone, LH, FSH, Oestradiol, Prolactin, liver function, and blood values. For men with low testosterone or TRT monitoring.
€ 175,00
Blood draw
Hormone Recovery (After Steroids)
Testosterone, free testosterone, SHBG, LH, FSH, estradiol, TSH, liver function, and lipid profile. For recovery after anabolic steroid use.
€ 325,00
Blood draw
Female Hormones Blood Test
Estradiol, FSH, LH, prolactin, and progesterone. For women with infertility, menstrual disorders, or menopausal symptoms.
€ 179,00
Blood draw
Expanded: Testosterone Replacement Therapy (TRT)
Testosterone, LH, FSH, estradiol, prolactin, blood values, complete liver function, kidney function, and lipid profile.
€ 235,00
Blood draw
Supplemental: Testosterone Replacement Therapy (TRT)
Complete hormonal analysis with testosterone, DHEA-S, thyroid, blood count, liver function, kidney function, lipids, glucose, HbA1c, insulin, hs-CRP, vitamin D and ferritin.
€ 335,00
Blood draw
Whoop (Advanced Labs)
Comprehensive blood analysis with biomarkers that integrates directly with your WHOOP wearable for optimal performance and recovery.
€ 385,00

How reliable is the test?

LH