Luteinizing Hormone: Low vs High Signs, Testing, Ovulation, and Testosterone
Overview
Luteinizing hormone, often shortened to LH, is a pituitary hormone that helps control ovulation in women and testosterone production in men. In the menstrual cycle, a sharp LH surge triggers the release of an egg. In the testes, LH tells cells to make testosterone, which supports libido, sperm production, and muscle and bone health.
Clinicians usually look at LH together with Follicle Stimulating Hormone and sex hormones when they are evaluating irregular periods, fertility issues, suspected polycystic ovary syndrome, or low testosterone patterns.
What Luteinizing Hormone is and where it is made
Luteinizing hormone is a peptide hormone produced by the pituitary gland at the base of the brain.
Its release is controlled by gonadotropin releasing hormone from the hypothalamus and by feedback from sex hormones such as estrogen and testosterone.
LH travels through the bloodstream to the ovaries in women and the testes in men, where it acts on specific cells.
What Luteinizing Hormone does in your body
Triggers ovulation in women by causing a mature ovarian follicle to release an egg.
Supports the formation and function of the corpus luteum, which makes progesterone in the second half of the cycle.
Stimulates Leydig cells in the testes to produce testosterone in men.
Helps regulate menstrual cycle timing, fertility, and sex hormone balance.
Contributes to sperm production indirectly through its role in testosterone production.
When testing Luteinizing Hormone makes sense
Irregular, very long, or very short menstrual cycles, or periods that stop unexpectedly.
Difficulty conceiving, especially when there is uncertainty about whether ovulation is occurring.
Suspected polycystic ovary syndrome when cycles, symptoms, and ultrasound findings suggest PCOS.
Evaluation of early or delayed puberty in children and adolescents.
Low libido, erectile problems, or low testosterone in men, where LH helps distinguish testicular from pituitary causes.
Workup of suspected pituitary or hypothalamic conditions affecting reproductive hormones.
How to think about high and low Luteinizing Hormone results
This information is general and does not replace lab specific reference ranges, cycle timing, or medical evaluation.
Low LH might be associated with:
Lack of ovulation, irregular or absent periods, and reduced fertility in women.
Low testosterone with low or inappropriately normal LH in men, suggesting a pituitary or hypothalamic cause.
Delayed puberty when combined with low sex hormone levels and other clinical features.
Possible contributors include hypothalamic amenorrhea from underfueling or high stress, pituitary or hypothalamic disease, some systemic illnesses, and long term use of certain hormones or medications that suppress the reproductive axis.
High LH might be associated with:
The normal mid cycle LH surge that triggers ovulation when timing is appropriate.
Menopause, when the ovaries are no longer responding and LH and FSH rise.
Polycystic ovary syndrome in some women, especially when the LH to FSH ratio is higher than usual.
Primary testicular failure in men, where the testes do not respond adequately and LH rises in compensation.
Markedly high LH can also be seen with some genetic or pituitary conditions. Interpretation depends on age, sex, cycle phase, and partner labs such as FSH, estrogen, progesterone, and testosterone.
What can influence your Luteinizing Hormone levels
Menstrual cycle phase and whether ovulation is approaching or has occurred.
Age and life stage, including puberty, reproductive years, and menopause.
Energy availability, body weight, and training load, especially in hypothalamic amenorrhea.
Chronic stress and illness that can suppress or alter hypothalamic and pituitary signals.
Hormonal contraception, fertility medications, or other hormone therapies.
Pituitary and hypothalamic health, including benign tumors, surgery, radiation, or trauma.
Time of day and sampling conditions, although cycle timing usually matters more than clock time.
When to talk to a clinician about Luteinizing Hormone
LH results that are outside the reference range and do not match your expected life stage or cycle timing.
Persistent irregular cycles, missed periods, or difficulty conceiving.
Symptoms suggestive of PCOS, such as irregular cycles, acne, or excess hair growth, especially with weight or metabolic changes.
Low libido, erectile problems, or confirmed low testosterone in men.
Concerns about early or delayed puberty in a child or adolescent.
A clinician can interpret LH alongside FSH, sex hormones, imaging, and your history to decide whether observation, lifestyle changes, further testing, or treatment is appropriate.
Luteinizing Hormone in one view
Luteinizing hormone is a pituitary signal that triggers ovulation in women and drives testosterone production in men, making it central to fertility, cycle health, and libido. On its own the number is hard to read, so it is most useful when timed correctly in the cycle and interpreted with Follicle Stimulating Hormone and key sex hormones. If your LH result is outside range or does not match your symptoms or life stage, it is a cue for a structured review with a clinician rather than a reason to self diagnose or change hormones on your own.
