Luteinizing Hormone: Functions, Test + Normal Range - SelfDecode Labs (2024)

Luteinizing hormone (LH) stimulates the testes in males and the ovaries in females. This hormone is vital for reproductive health, with both high and low levels associated with low fertility and other reproductive issues. This post goes into detail about LH functions, tests, and normal range, along with suggestions for improving reproductive health.

What is Luteinizing Hormone?

Luteinizing hormone (LH) a hormone released by the pituitary gland in response to luteinizing hormone-releasing hormone (LHRH), which is released from the hypothalamus [1].

LH is a gonadotropic hormone and controls the functions of the female ovaries and male testes. It is also essential for proper reproductive function.

In males, it is also called the Interstitial cell-stimulating hormone (ICSH) [2].

In general, when estrogen and progesterone levels fall, LH levels rise. Follicle Stimulating Hormone (FSH) is synergistic with LH.

Function In Women

In women, luteinizing hormone (LH) carries out different roles in the two halves of the menstrual cycle.

In weeks 1-2 of the cycle, LH is required to stimulate the ovarian follicles in the ovary to produce the female sex hormone, estradiol.

Later a “surge” in LH levels causes ovulation. In the remainder of the cycle, LH stimulates the corpus luteum to produce progesterone which is required to support the early stages of pregnancy, if fertilization occurs [1].

Function In Men

Luteinizing hormone stimulates Leydig cells in the testes to produce testosterone. If testosterone levels decrease, LH secretion increases. This is known as negative feedback.

Testosterone, in turn, stimulates sperm production as well as generating male characteristics throughout the body [1].

Luteinizing Hormone Test

An LH test measures the amount of Luteinizing Hormone in the sample of blood or urine. It may be done to find the cause of a couple’s inability to become pregnant. LH test is commonly used to evaluate [3, 4]:

• A woman’s egg supply (ovarian reserve)
• A man’s sperm count
• Menstrual problems in women.
• A women’s response to medicines taken to stimulate ovulation.

Normal Range

Depending on the sex, phase of the cycle, and other factors, normal LH blood levels may vary [5, 6]:

• women in the follicular phase of the menstrual cycle: 1.9 to 12.5 IU/L
• women at the peak of the menstrual cycle: 8.7 to 76.3 IU/L
• women in the luteal phase of the menstrual cycle: 0.5 to 16.9 IU/L
• pregnant women: less than 1.5 IU/L
• women past menopause: 15.9 to 54.0 IU/L
• women using contraceptives: 0.7 to 5.6 IU/L
• men between the ages of 20 and 70: 0.7 to 7.9 IU/L
• men over 70: 3.1 to 34.0 IU/L

Low Luteinizing Hormone

LH levels are a marker of reproductive health. Low or high levels don’t necessarily indicate a problem if there are no symptoms or if your doctor tells you not to worry about it.

Luteinizing hormone (LH) deficiency is uncommon on its own; LH deficiency almost always occurs with follicle-stimulating hormone (FSH) deficiency because these hormones are secreted by the same sets of cells [7, 8].

Signs & Symptoms

• Irregular or absent menstrual periods (in women) [9]
• Loss of body and facial hair (in men) [10]
• Erectile dysfunction and/or decreased libido (in men) [10]
• Infertility in both women and men [1, 11]

Potential Causes

• Hypopituitarism [12]
• Hypogonadism [13, 14]
• Delayed puberty [15]
• Kallmann’s syndrome [16] – caused by a deficiency in gonadotropin-releasing hormone (i.e., LHRH). It can result in a lack of sexual development, a small penis, undeveloped testes, and a delay in or lack of puberty [16].

Other:

• Smoking cigarettes and marijuana [17, 18]
• Vitamin D deficiency [19, 20, 21]
• Tumors in the pituitary gland [22]
• Digoxin (Lanoxin or Digox) treatment [23]

Low LH? Ways to Improve Reproductive Health

Improving your LH levels won’t necessarily cause improvement in reproductive health. The following is a list of complementary approaches to improve reproductive health that may also balance low LH levels. Though studies suggest various dietary and lifestyle factors may increase LH levels, additional large-scale studies are needed.

Remember to talk to your doctor before making any major changes to your day-to-day routine.

Lifestyle:

• Ceasing smoking or marijuana use [17, 18]

Supplements:

• D-aspartic acid [24]
• Forskolin [25]
• Resveratrol [26]
• Omega 3 [27]
• Vitamin D [20]
• Garlic [28, 29, 30]
• Licorice (in men) [31]

High Luteinizing Hormone

LH levels are a marker of reproductive health. Low or high levels don’t necessarily indicate a problem if there are no symptoms or if your doctor tells you not to worry about it.

High luteinizing hormone (LH) levels may cause fertility problems. Some women with high LH have lower rates of fertilization and pregnancy [1].

In men, high levels may indicate testicular failure and infertility [32].

High LH levels are seen in genetic conditions such as Klinefelter’s syndrome. It shrinks the testes and causes them to not produce enough testosterone [33].

Associated Conditions

In postmenopausal women, an increase in LH levels may play a role in Alzheimer’s Disease development. LH has been shown to promote the deposition of amyloid β plaques in the hippocampus, as seen in Alzheimer’s [34].

Signs & Symptoms

• Absent or irregular menstrual cycles (in women) [35]
• Infertility in both women and men [36, 11]

Potential Causes

• Polycystic ovary syndrome (PCOS) [37, 9]
• Early (precocious) puberty [38]
• Genetic abnormalities (mutations in the luteinizing hormone/chorionic gonadotropin receptor that cause ambiguous genitalia and infertility) [39]
• Tumors in ovaries [40]
• Thyroid disorders [41]

Testicular failure can also cause high luteinizing hormone levels. This can be caused by:

• Thyroid disorders [42]
• Viral infections [43]
• Tumors [44]
• Radiation [45]
• Radiation therapy [46]
• Chromosomal disorders, such as Klinefelter syndrome [47]

High LH? Ways to Improve Reproductive Health

Improving your LH levels won’t necessarily cause improvement in reproductive health. The following is a list of complementary approaches to improve reproductive health that may also balance high LH levels. Though studies suggest various dietary and lifestyle factors may lower LH, additional large-scale studies are needed.

Remember to talk to your doctor before making any major changes to your day-to-day routine.

Lifestyle:

• Exercising regularly [48]

Supplements:

• Black cohosh [49]
• Vitex agnus-castus (chasteberry) [50]
• Licorice (in women) [51]

Other:

Testosterone can inhibit the luteinizing hormone. Check your testosterone levels, and lifestyle and supplement suggestions associated with testosterone [52].