What is Luteinizing Hormone (LH) ?
In women, a mid-cycle surge in LH triggers ovulation and supports formation of the corpus luteum, which produces progesterone. In men, LH stimulates Leydig cells in the testes to produce testosterone. Because LH responds directly to gonadal feedback, abnormal levels can help distinguish between problems originating in the ovaries or testes and those involving the hypothalamus or pituitary gland.
Why Test for for LH ?
Evaluating LH helps clinicians assess reproductive function, ovulation, and pituitary-gonadal signaling. LH testing is commonly used to investigate:
• Irregular or absent menstrual cycles
• Ovulatory dysfunction and infertility
• Perimenopause and menopause
• PCOS and androgen excess
• Low testosterone or hypogonadism in men
• Testicular or ovarian dysfunction
• Delayed or precocious puberty
• Pituitary or hypothalamic disorders
• Monitoring certain fertility treatments
Clinical Significance of LH
- Low LH Levels: Low LH—generally <2 mIU/mL in reproductive-age women during the follicular phase or <1.5–2 mIU/mL in adult men—may reflect reduced hypothalamic or pituitary signaling. Causes can include hypothalamic dysfunction, pituitary disorders, hyperprolactinemia, significant caloric restriction, or suppression from exogenous hormones. Low LH may contribute to impaired ovulation, irregular or absent menstrual cycles, reduced testosterone production, and infertility.
- High LH Levels: High LH may indicate reduced ovarian or testicular feedback. In women, levels persistently above ~10–15 mIU/mL outside the mid-cycle surge may occur with PCOS, diminished ovarian function, or menopause, while menopausal levels commonly rise above ~15–25 mIU/mL. In men, levels above ~8–10 mIU/mL may suggest primary testicular dysfunction, particularly when testosterone is low.
Actionable Insights
LH should be interpreted alongside age, sex, menstrual cycle timing, symptoms, and other reproductive hormones. In women, the relationship between LH, FSH, estradiol, and progesterone helps assess ovulation and ovarian function. In men, LH should be evaluated with testosterone and FSH to help distinguish primary testicular dysfunction from hypothalamic or pituitary causes.
Hormonal contraceptives, hormone replacement therapy, fertility medications, and other treatments can alter LH levels. Monitoring hormone patterns and trends often provides more insight than a single measurement.
Serum vs. Saliva Testing: Serum is the standard specimen for assessing LH and pituitary-gonadal function. Salivary LH testing is not routinely used or as well established for clinical assessment, so serum and saliva results should not be directly compared.
Optimal Ranges
| Women | Men |
| Premenopausal |
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| Postmenopausal: ~8–60 mIU/mL |
Note: Reference ranges vary by laboratory. In functional medicine, some providers may consider a narrower interpretive window to help guide clinical context. These values are not standardized and should be interpreted in conjunction with the ordering provider’s judgment.
“You cannot use a single LH value as definitive. LH is secreted in pulses every 60–90 minutes with a circulating half-life of only about 20–30 minutes; a random draw can easily land in a trough and miss true
central hypogonadism. To be accurate, you need to draw two or three samples 15–20 minutes apart.”
Dr. Mitch Ghen - Director of Physician Consultations, Access Labs
Disclaimer: Content on the Access Labs blog is for informational purposes only and reflects the views of individual contributors, not necessarily those of Access Labs. We do not endorse specific treatments, products, or protocols. This content is not a substitute for professional medical advice. Always consult a qualified healthcare provider regarding any medical concerns.
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