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Hormones

LH blood test: how to read your result

LH is produced by the pituitary gland and triggers ovulation in females and stimulates testosterone production in males. It works in concert with FSH to regulate reproduction.

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Here you can understand your LH result in the context of your full lab report.

Upload your PDF and get a plain-English explanation based on your actual LH value, your lab’s reference range, and other hormone markers.

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  • Understand high, low, or borderline values
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Educational only — no diagnosis, no medication advice.

Questions you can ask after uploading

  • “What does my LH result mean?”
  • “Is it above, below, or within my lab's range?”
  • “How does it fit with the rest of my report?”

What this marker measures

LH and FSH are always interpreted together and in the context of the menstrual cycle phase (for females) or clinical symptoms. The LH:FSH ratio is sometimes used in evaluating PCOS.

High or low: what it can mean

High LH

In females, a dramatic LH surge triggers ovulation. Persistently high LH outside of ovulation may indicate polycystic ovary syndrome or menopause. In males, high LH may signal reduced testicular function.

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Low LH

Low LH can impair fertility by preventing ovulation in females and reducing testosterone production in males. Causes include hypothalamic/pituitary conditions, eating disorders, or excessive exercise.

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Reference ranges for LH are typically reported in mIU/mL. Exact normal ranges vary by lab, sex, and age — your lab report shows the range used to flag your specific result.

Frequently asked questions

What is LH?

+

LH is produced by the pituitary gland and triggers ovulation in females and stimulates testosterone production in males. It works in concert with FSH to regulate reproduction.

What does LH measure?

+

LH and FSH are always interpreted together and in the context of the menstrual cycle phase (for females) or clinical symptoms. The LH:FSH ratio is sometimes used in evaluating PCOS.

What does high LH mean?

+

In females, a dramatic LH surge triggers ovulation. Persistently high LH outside of ovulation may indicate polycystic ovary syndrome or menopause. In males, high LH may signal reduced testicular function.

What does low LH mean?

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Low LH can impair fertility by preventing ovulation in females and reducing testosterone production in males. Causes include hypothalamic/pituitary conditions, eating disorders, or excessive exercise.

Related biomarkers

  • Testosterone
    Total Testosterone
  • Estradiol
    Estradiol (E2)
  • Cortisol
    Serum Cortisol
  • DHEA-S
    Dehydroepiandrosterone Sulfate
  • FSH
    Follicle Stimulating Hormone
  • Prolactin
    Serum Prolactin

Editorial note

LabTestly explains lab markers using plain-English educational content. Reference ranges may vary by laboratory and should be interpreted with a clinician.

Educational content · Editorially reviewed for clarity · Last updated 23 October 2026

Common sources used for lab-test education

  • MedlinePlus
  • Mayo Clinic
  • Cleveland Clinic
  • Labcorp
  • Quest Diagnostics

Not medical advice

This page is for general understanding only and does not replace medical advice from your clinician. Reference ranges can vary by laboratory, age, sex, pregnancy status, medications, and clinical context.

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LabTestly is an educational tool and is not intended to provide medical advice, diagnosis, or treatment. Always consult a qualified healthcare professional.