Guide to Luteinizing hormone (LH)

WRITTEN BY

The Levels Team

Updated: 05/22/2025|12 min read

Summary

Luteinizing hormone (LH) is a reproductive hormone produced by the pituitary gland in both men and women. LH helps regulate ovulation and progesterone production in women and testosterone production in men.

Why It Matters

LH plays a vital role in sexual development and fertility. In females, LH helps control the menstrual cycle. It rises mid-cycle to trigger ovulation---the release of a mature egg from the ovary. (This LH surge is what ovulation predictor kits detect, helping women identify their most fertile days.) After this surge, levels drop quickly, and the corpus luteum starts ramping up progesterone. 

In men, LH stimulates specialized cells in the testes, called Leydig cells, to produce testosterone, the primary male sex hormone. This steady production is important for male sexual development, fertility, and overall health.

Testing LH levels provides information about fertility, menstrual irregularities, early or delayed puberty, and medical conditions that can affect hormone levels. The test is usually interpreted alongside other hormone tests.

Associated Symptoms 

LH levels themselves are laboratory findings rather than medical conditions. However, abnormal levels may be associated with various health issues, each with its own symptoms.

Common symptoms that may indicate conditions associated with high LH levels:

• Irregular or absent menstrual periods: May indicate diminished ovarian function or approaching menopause
• Difficulty getting pregnant: May result from ovulation disruption despite high LH levels
• Menopause symptoms: May include hot flashes and vaginal dryness due to hormonal changes
• Low testosterone symptoms in men: May include reduced libido, erectile dysfunction, and fatigue despite the body's attempt to stimulate testosterone production
• Delayed puberty in children: May occur when the body produces high LH but reproductive organs don't respond properly

Common symptoms that may indicate conditions associated with low LH levels:

• Delayed puberty: May occur when insufficient LH prevents normal sexual development and maturation
• Loss of pubic hair: May develop with prolonged LH deficiency affecting secondary sexual characteristics
• Infertility: May result when inadequate LH prevents proper ovulation or testosterone production
• Irregular or no menstrual periods: May occur from insufficient hormonal stimulation of the ovaries
• Issues producing breast milk: May be related to hormonal imbalances affecting prolactin
• Hot flashes (in women): May occur with fluctuating hormone levels despite low LH
• Lack of ovulation: May happen when insufficient LH prevents the ovulatory surge needed to release mature eggs
• Poor sperm production (in men): May result from inadequate testosterone stimulation
• Erectile dysfunction: May develop from low testosterone due to insufficient LH
• Low libido: May reflect reduced sexual desire related to hormonal imbalances
• Fatigue: May present as general tiredness resulting from hormonal deficiencies

It's important to note that many people with abnormal LH levels may experience no symptoms at all, especially with mild imbalances. The pattern, severity, and progression of symptoms, combined with laboratory findings, may help healthcare providers determine the underlying cause.

Clinical Ranges

Female

• Follicular Phase: 1.9-12.5 mIU/mL
• Mid-Cycle Peak: 8.7-76.3 mIU/mL
• Luteal Phase: 0.5-16.9 mIU/mL
• Postmenopausal: 10.0-54.7 mIU/mL

Male

• 18-59 Years: 1.5-9.3 mIU/mL
• ≥60 Years: 1.6-15.2 mIU/mL

Lifestyle Factors That Can Impact It

Activities that may negatively impact on LH levels include:

• Excessive exercise. Exercising too much can suppress LH production. 
• Underweight and overweight: Both significant weight loss and obesity can disrupt LH production and release. Studies show that women with a BMI below 18.5 or above 30 often have abnormal LH patterns. 
• Stress: Chronic stress can affect the hypothalamic-pituitary axis, which affects LH production. Stress reduction techniques may help maintain healthy hormone levels.
• Poor sleep habits: Poor sleep can disrupt hormone production. Maintaining good sleep hygiene can support healthy LH levels.

Other Factors That Can Impact It

Medical Conditions

• Polycystic ovary syndrome (PCOS): A metabolic and hormonal disorder that can often cause extra ovarian cyst formation along with blood sugar and insulin dysregulation.
• Primary ovarian insufficiency:  When ovaries stop functioning normally before age 40, LH levels typically rise as the body tries to stimulate ovarian function
• Hypothalamic amenorrhea: A condition where hormone imbalances stop menstruation, often due to low body weight, excessive exercise, or stress.
• Hypogonadism: Primary hypogonadism (testicular or ovarian failure) leads to elevated LH. Secondary hypogonadism (pituitary or hypothalamic dysfunction) results in low LH levels.
• Pituitary tumors: Both benign and malignant tumors can affect LH production and release. Prolactinomas, the most common type of pituitary tumor, can suppress LH release.

Medications and Supplements

• Hormonal birth control
• GnRH agonists and antagonists
• Opioids and certain antipsychotic medications
• Anabolic steroids
• Corticosteroids

Individual Factors

• Age: LH levels naturally change throughout life, significantly increasing during puberty and menopause in women.
• Sex: Normal reference ranges differ between males and females.
• Menstrual cycle phase: In women, LH levels fluctuate dramatically throughout the menstrual cycle, with a sharp surge before ovulation.
• Pregnancy:  LH levels are typically low during pregnancy.
• Menopause: After menopause, LH levels remain consistently elevated due to a lack of ovarian feedback.

Testing Accuracy and Stability

LH tests are generally accurate, but doctors will interpret results in the context of reproductive status, age, and other hormone levels.

Factors That Can Affect the Accuracy of Your Test 

• Day of menstrual cycle (in women)
• Time of day: LH is secreted in pulses throughout the day, with levels typically higher in the morning.
• Recent sexual activity: Can temporarily alter hormone levels (in men)

How It Relates to Other Markers

Other tests can provide insights about health status when viewed alongside luteinizing hormone results. These tests may include:

• Follicle-stimulating hormone (FSH): Works closely with LH in reproductive function and helps distinguish between different hormone disorders.
• Estradiol: Estradiol levels can shed light on ovarian function and pituitary health in women.
• Progesterone: Testing progesterone about 7 days after presumed ovulation confirms whether ovulation occurred.
• Testosterone: Important for assessing male reproductive health and pituitary issues in men, but it can also be an indicator of hormonal imbalances in the female body
• Thyroid function tests: Thyroid disorders can affect reproductive hormone levels and should be evaluated alongside LH.
• Prolactin: Elevated prolactin can suppress LH secretion, mimicking other hormonal disorders. This test helps rule out prolactinomas (pituitary tumors) and other conditions.

What Results May Mean in the Context of Other Markers

• The LH:FSH ratio: FSH is typically higher than LH; 1:1 may be a sign that something is off. In PCOS, the LH:FSH ratio is often elevated (2:1 or 3:1).
• High LH + low estradiol: Can suggest ovarian failure (primary hypogonadism).
• Low LH + normal or high estradiol: May indicate a pituitary problem.
• High LH + low testosterone: May suggest primary testicular failure.
• Normal/low LH + low testosterone: May indicate a hypothalamic-pituitary issue.

Follow-Up Considerations

If your LH levels are low or high, your provider may make some of the following recommendations. You should always speak to your doctor if you have medical questions or before making medical decisions.

When Re-Testing May Be Appropriate

• After 2-3 months if making lifestyle changes to improve hormonal balance
• If symptoms worsen or new symptoms develop
• For women, testing on specific days of the menstrual cycle
• Before and during fertility treatments to monitor the response

Additional Testing Your Doctor May Consider

• Complete hormonal panel (FSH, estradiol/testosterone, prolactin)
• Thyroid function tests
• Pelvic or testicular ultrasound to evaluate reproductive organ structure
• Anti-Müllerian hormone (AMH) for women concerned about ovarian reserve

When Additional Care May Be Warranted

• If you're trying to conceive and haven't succeeded after 12 months (or 6 months if over 35)
• If experiencing symptoms of early menopause under age 40
• If menstrual periods stop suddenly or become highly irregular
• For men experiencing symptoms of low testosterone
• If puberty is delayed or developing abnormally in adolescents

Bibliography