LH (Luteinizing Hormone)

What It Is

LH (luteinizing hormone) is a signaling hormone produced by the pituitary gland in the brain. Its primary job is to trigger ovulation (the release of an egg from the ovary) and stimulate progesterone production. During reproductive years, LH surges mid-cycle, causing ovulation and initiating the second half of the menstrual cycle. During perimenopause and menopause, LH levels rise (like FSH) as the ovaries become less responsive—though LH is less commonly tested than FSH as a marker of menopause.

Where it's produced:

• Pituitary gland → a pea-sized gland at the base of the brain
• Part of the hypothalamic-pituitary-ovarian (HPO) axis (the hormonal system that regulates the menstrual cycle and reproductive function)

Primary functions:

• Triggers ovulation → the mid-cycle LH surge (a dramatic spike in LH levels) causes the dominant follicle to release an egg
• Stimulates progesterone production → after ovulation, LH signals the corpus luteum (the follicle that released the egg) to produce progesterone
• Works alongside FSH → FSH stimulates follicle maturation and estrogen production; LH triggers ovulation and progesterone production
• Rises during menopause → like FSH, LH rises as the ovaries become less responsive to the brain's signals

How LH works during reproductive years:

1. First half of the menstrual cycle (follicular phase, days 1-14):

   • LH is low (FSH is dominant during this phase)
   • Follicles mature in response to FSH, producing estrogen

2. Mid-cycle (around day 14):

   • Estrogen peaks → triggers a massive LH surge (LH levels spike 2-10x within 24-48 hours)
   • LH surge triggers ovulation → the dominant follicle ruptures, releasing the egg (typically 12-36 hours after LH surge begins)
   • This is how ovulation predictor kits (OPKs) work—they detect the LH surge in urine

3. Second half of the cycle (luteal phase, days 15-28):

   • LH remains elevated (but lower than the mid-cycle surge)
   • LH stimulates the corpus luteum (the follicle that released the egg) to produce progesterone
   • Progesterone prepares the uterine lining for potential pregnancy
   • If pregnancy doesn't occur, progesterone drops, triggering menstruation

What changes during perimenopause and menopause:

As women age, the ovaries become less responsive to both FSH and LH. The brain (pituitary gland) senses low or erratic estrogen and progesterone levels, so it produces more LH (and FSH) in an attempt to stimulate the ovaries. The ovaries don't respond adequately, so LH keeps rising.

Result:

• High LH = ovaries are struggling to respond = perimenopause or menopause
• Very high LH (consistently above 20-30 mIU/mL) = menopause (ovaries have stopped responding)

LH vs. FSH:

• FSH is more commonly tested → FSH is the standard marker for assessing menopausal status
• LH follows a similar pattern → both rise during perimenopause and menopause as ovaries decline
• LH testing is less informative → because LH surges are normal during the menstrual cycle (mid-cycle LH surge for ovulation), an elevated LH doesn't always indicate menopause (could just be ovulation)
• FSH is more stable → FSH rises gradually, making it easier to interpret; LH is more variable

Why LH testing is rarely done:

1. FSH is sufficient → if FSH is elevated (> 25-40 mIU/mL), LH is almost always elevated too; testing both doesn't add much clinical value
2. LH is more variable → because of the mid-cycle LH surge, an isolated elevated LH can be hard to interpret
3. Menopause is diagnosed clinically → 12 months without a period is the gold standard; hormone tests (FSH, LH) provide supporting information but aren't necessary for diagnosis

When LH testing might be done:

• Alongside FSH → some clinicians test both FSH and LH to assess menopausal status (though FSH alone is usually sufficient)
• To assess pituitary function → in rare cases where pituitary dysfunction is suspected (both FSH and LH would be low, rather than high)
• Infertility workup → to confirm ovulation (LH surge detection) or assess hormonal imbalance (PCOS, hypogonadism)

Why It Matters During Perimenopause/Menopause

LH is the body's way of trying to trigger ovulation and progesterone production, even as the ovaries become less responsive. Like FSH, LH rises as the brain (pituitary gland) attempts to compensate for declining ovarian function.

The pattern:

Early perimenopause:

• LH begins to rise (intermittently) → some cycles have elevated LH, others have normal LH
• Ovaries are still responding to LH some of the time → ovulation occurs sporadically
• LH surge may still occur (triggering ovulation), but it may be less robust or absent in anovulatory cycles
• LH is variable → can be high one month (if no ovulation), normal the next (if ovulation occurs)

Mid-perimenopause:

• LH is erratic and often elevated → the brain is working harder to trigger ovulation, but ovarian response is inconsistent
• Some cycles have high LH with no ovulation → no progesterone production → estrogen dominance
• LH surges may be absent (anovulatory cycles) or weak
• Cycles become more irregular

Late perimenopause:

• LH is consistently elevated (often > 20-30 mIU/mL) → ovaries are barely responding
• Ovulation is rare or absent
• Progesterone production is minimal or absent
• Periods are infrequent

Menopause:

• LH is consistently high (typically > 20-40 mIU/mL, often higher) → ovaries have stopped responding
• No ovulation, no progesterone
• No more periods
• LH stabilizes at high levels → the brain continues to send LH, but the ovaries are no longer listening

Post-menopause:

• LH remains elevated for years (often > 20-50+ mIU/mL)
• Over time, LH may decline slightly but remains well above reproductive levels

Why LH testing is less useful than FSH:

1. LH surges are normal mid-cycle → an elevated LH could be ovulation (normal) or menopause (ovarian decline); context matters
2. FSH is more stable → easier to interpret
3. Both rise together → if FSH is high, LH is almost always high too; testing both doesn't add much information
4. Clinical diagnosis is key → 12 months without a period is the gold standard for menopause, not LH levels

How It Works

Mechanism of action:

LH is part of the hypothalamic-pituitary-ovarian (HPO) axis, a feedback loop that regulates the menstrual cycle:

1. Hypothalamus (brain) releases GnRH (gonadotropin-releasing hormone)
2. Pituitary gland (brain) responds to GnRH → releases LH (and FSH)
3. Ovaries respond to LH:
   • Mid-cycle LH surge → triggers ovulation (release of egg)
   • After ovulation, LH stimulates corpus luteum → produces progesterone
4. Progesterone and estrogen feed back to brain → tell hypothalamus and pituitary to reduce LH and FSH (negative feedback loop)
5. When progesterone/estrogen drop (end of cycle, or perimenopause), the brain increases LH and FSH

During perimenopause and menopause, this feedback loop breaks down:

• Ovaries become less responsive to LH → ovulation becomes sporadic or stops entirely
• Brain senses low progesterone/estrogen → increases LH (and FSH) to try to stimulate the ovaries
• Ovaries don't respond adequately → LH keeps rising
• Eventually, ovaries stop responding entirely → LH remains persistently elevated → menopause

LH's relationship with other hormones:

LH + FSH (Follicle-Stimulating Hormone):

• Work together to regulate the menstrual cycle
• FSH stimulates follicle maturation and estrogen production (first half of cycle)
• LH triggers ovulation and progesterone production (mid-cycle and second half of cycle)
• Both rise during menopause (ovaries are no longer responding to either signal)
• FSH is more commonly tested, but LH follows a similar pattern

LH + Estrogen:

• Estrogen triggers the LH surge → when estrogen peaks mid-cycle, it signals the pituitary to release a massive surge of LH
• LH surge triggers ovulation → ovulation occurs 12-36 hours after LH surge begins
• In perimenopause: Estrogen is erratic → LH surges may be absent, weak, or irregular
• In menopause: Estrogen is consistently low → LH is persistently elevated (brain is trying to stimulate ovulation, but ovaries can't respond)

LH + Progesterone:

• LH stimulates progesterone production → after ovulation, LH signals the corpus luteum to produce progesterone
• When ovulation doesn't occur (anovulatory cycle), no corpus luteum forms → no progesterone production (even if LH is high)
• Result: High LH in perimenopause often correlates with low progesterone (because ovulation isn't happening)

LH + Testosterone:

• In women, LH also stimulates the ovaries to produce small amounts of testosterone (and other androgens)
• As ovaries decline, testosterone production decreases (though adrenals continue to produce some)
• High LH in menopause doesn't restore testosterone production (ovaries are no longer responding)

What It Looks Like

When LH Is Normal (Reproductive Years)

Lab values:

• Follicular phase (first half of cycle): 1-12 mIU/mL
• Mid-cycle LH surge: 20-100+ mIU/mL (dramatic spike, lasts 24-48 hours)
• Luteal phase (second half of cycle): 1-15 mIU/mL (slightly elevated to support corpus luteum)

What it means:

• Ovaries are responding normally to LH
• Ovulation is occurring (mid-cycle LH surge)
• Progesterone is being produced (corpus luteum is functioning)
• Menstrual cycles are regular and ovulatory

When LH Begins to Rise (Early Perimenopause)

Lab values:

• LH: 10-25 mIU/mL (intermittent or variable, outside of mid-cycle surge)
• May be high one month, normal the next

What it means:

• Ovaries are becoming less responsive
• Brain is working harder to trigger ovulation
• Ovulation is less consistent → some cycles are anovulatory
• Progesterone production is erratic (depends on whether ovulation occurs)

What you might notice:

• Menstrual cycles become irregular (longer, shorter, skipped periods)
• Symptoms of low progesterone (anxiety, insomnia, heavy bleeding, breast tenderness)
• Occasional symptoms of low estrogen (hot flashes, night sweats, brain fog)

When LH Is Elevated and Variable (Mid-Perimenopause)

Lab values:

• LH: 15-40+ mIU/mL (fluctuates)
• Can be high one week, lower the next (but generally trending upward)

What it means:

• Ovarian function is erratic
• Brain is sending a lot of LH, but ovaries respond inconsistently
• Ovulation is sporadic → progesterone production is inconsistent

What you might notice:

• Wild hormonal fluctuations → mood swings, energy swings, libido swings
• Cycles become very irregular (long, short, skipped periods)
• Progesterone deficiency symptoms intensify (anxiety, insomnia, irritability)
• Hot flashes and night sweats become more frequent

When LH Is Consistently Elevated (Late Perimenopause/Menopause)

Lab values:

• LH: 20-50+ mIU/mL (consistently elevated)
• Often > 30-40 mIU/mL in established menopause

What it means:

• Ovaries are barely responding or not responding at all
• No ovulation, no progesterone
• Estrogen is consistently low

What you might notice:

• Menopausal symptoms intensify → hot flashes, night sweats, vaginal dryness, sleep disruption, mood changes
• Periods are infrequent or absent
• Once 12 months have passed without a period → confirmed menopause
• LH remains high indefinitely (this is the new normal)

Phase Impact

Baseline (Regular Cycle, Pre-Perimenopause): LH rises and falls predictably with the menstrual cycle. LH is low in the first half of the cycle, surges mid-cycle (triggering ovulation), then remains slightly elevated in the second half (supporting progesterone production). Ovaries respond well to LH. Ovulation occurs regularly. Progesterone production is healthy.

Electric Cougar (Early Perimenopause): LH begins to rise intermittently as ovaries become less responsive. Some cycles have normal LH surges (triggering ovulation); others have absent or weak LH surges (anovulatory cycles). Ovulation becomes inconsistent → progesterone production declines. LH levels fluctuate (high in anovulatory cycles, normal when ovulation occurs). Menstrual cycles may become irregular.

Wild Tide (Mid-Perimenopause): LH is erratic and often elevated (15-40+ mIU/mL), fluctuating unpredictably. The brain is working hard to trigger ovulation, but ovarian response is inconsistent. Ovulation is sporadic. Progesterone is low or absent. Cycles become very irregular. LH levels mirror the hormonal chaos of this phase (though LH testing is rarely done, so this is less clinically visible than FSH).

Henapause (Late Perimenopause, 7-11 Months Without Period): LH is consistently elevated (typically > 20-30 mIU/mL). Ovaries are barely responding. Ovulation is rare or absent. Progesterone is absent. Periods are infrequent or have stopped. LH remains high as the body attempts to trigger ovulation, but the ovaries no longer respond.

The Pause (Menopause, 12+ Months Without Period): LH is consistently high (typically > 20-40 mIU/mL, often higher). Ovaries have stopped responding to LH. No ovulation, no progesterone. No more periods. LH stabilizes at elevated levels—this is the new baseline. LH will remain high for the rest of life (though it may decline slightly over many years).

Phoenix Phase (Early Post-Menopause, 2-10 Years After Last Period): LH remains elevated (20-50+ mIU/mL). Ovarian function has ceased. Progesterone remains absent (unless supplemented via HRT). LH levels are no longer clinically useful (menopause is already established). The body has adapted to the new hormonal baseline.

Golden Sovereignty (Established Post-Menopause, 7+ Years After Last Period): LH remains elevated, though it may decline slightly over time (still well above reproductive levels). Ovarian function remains absent. Progesterone remains absent (unless supplemented). LH testing is rarely needed at this stage.

Testing & Optimization

When to Test

LH testing is rarely necessary for diagnosing perimenopause or menopause (FSH is the preferred marker, and clinical diagnosis—12 months without a period—is the gold standard).

When LH testing might be done:

1. Infertility workup:

   • To confirm ovulation → LH surge detection (via blood test or urine ovulation predictor kits)
   • To assess hormonal balance → LH:FSH ratio can help diagnose PCOS (polycystic ovary syndrome), where LH is often higher than FSH

2. Alongside FSH to assess menopausal status:

   • Some clinicians test both FSH and LH (though FSH alone is usually sufficient)
   • LH > 20-30 mIU/mL + FSH > 25-40 mIU/mL + 12 months without period → confirms menopause

3. To assess pituitary function:

   • In rare cases where pituitary dysfunction is suspected (both FSH and LH would be low, rather than high)

When LH testing is NOT useful:

1. To diagnose perimenopause:

   • LH fluctuates too much (can be high due to anovulation or normal mid-cycle surge)
   • Perimenopause is diagnosed clinically (age, symptoms, irregular cycles), not by LH

2. To confirm menopause:

   • 12 months without a period is the gold standard (LH testing is not necessary)
   • If hormone testing is desired, FSH alone is sufficient

3. To monitor HRT effectiveness:

   • Once on HRT, LH levels don't matter → the goal is symptom relief, not specific LH numbers

What the test measures:

• Serum LH (blood test): Most common
• Timing matters: For ovulation detection, test mid-cycle (around day 14); for menopause assessment, timing is less critical

Normal ranges (vary by lab and context):

• Follicular phase: 1-12 mIU/mL
• Mid-cycle (ovulation): 20-100+ mIU/mL (LH surge)
• Luteal phase: 1-15 mIU/mL
• Menopause: > 20-40 mIU/mL (often 30-50+ mIU/mL)

Optimization Strategies

You cannot "optimize" LH directly—it's a reflection of ovarian function.

LH is not the problem; it's the signal that the ovaries are declining.

What you CAN do:

1. Address symptoms with HRT (if desired):

• Estrogen therapy replaces the estrogen the ovaries are no longer producing
• Progesterone therapy replaces the progesterone that's absent (due to lack of ovulation)
• HRT improves symptoms (hot flashes, night sweats, vaginal dryness, mood, sleep, bone health, etc.)
• HRT may or may not lower LH → and that's okay; the goal is symptom relief, not lowering LH

2. Support overall hormonal health:

• Reduce stress → chronic stress can worsen hormonal dysregulation
• Optimize nutrition → adequate protein, healthy fats, micronutrients
• Prioritize sleep → supports HPA axis and hormonal balance
• Exercise moderately → supports metabolic health, bone density, mood

3. If fertility is the goal (and LH is elevated):

• Consult a reproductive endocrinologist → high LH (and FSH) indicates diminished ovarian reserve; fertility treatments (IVF, donor eggs) may be options
• Lifestyle optimization → stress management, nutrition, sleep, avoid smoking/excessive alcohol

4. If early menopause/POI is diagnosed (high LH before age 40):

• HRT is strongly recommended (until at least age 50-51) → to protect bone health, cardiovascular health, cognitive health, and quality of life
• Bone density screening → monitor with DEXA scans
• Cardiovascular health → prioritize heart-healthy lifestyle
• Fertility options → if pregnancy is desired, discuss egg donation with reproductive specialist
• Emotional support → therapy, support groups

When to Review with Clinician

You should discuss LH testing if:

• Trying to conceive and want to confirm ovulation (LH surge detection via blood test or urine OPKs)
• Suspected PCOS or other hormonal imbalance (LH:FSH ratio can be informative)
• Periods have stopped before age 40 (possible premature ovarian insufficiency → FSH and LH testing may be done together)
• Clinician recommends LH testing alongside FSH to assess menopausal status (though FSH alone is usually sufficient)

You do NOT need LH testing if:

• You're clearly in perimenopause (irregular cycles, symptoms) → clinical diagnosis is sufficient
• You're clearly in menopause (12+ months without period) → LH testing won't change diagnosis or treatment
• You're on HRT and it's working well → LH levels don't matter once symptoms are managed

Red flags requiring medical attention:

• Periods stop before age 40 → requires evaluation for premature ovarian insufficiency (FSH and LH may be tested, along with other workup)
• Very high LH with continued heavy or irregular bleeding → may indicate other issues (fibroids, polyps, hyperplasia, cancer) → requires further evaluation

Related Terms

• fsh-follicle-stimulating-hormone
• estrogen
• progesterone
• menopause
• perimenopause
• ovulation
• anovulation
• wild-tide
• electric-cougar-puberty
• hot-flashes
• night-sweats
• premature-ovarian-insufficiency