Luteinising Hormone (LH)
LH is the pituitary signal that tells the testes to produce testosterone. Reading LH alongside total T classifies whether low testosterone is primary (testes problem) or secondary (pituitary problem) — which decides whether the upstream cause is treatable.
- Category
- Hormones
- Units
- IU/L
- Reference range
- 1.7-8.6 IU/L (men)
What does a high Luteinising Hormone result mean?
High LH with low T = primary hypogonadism (the testes aren't responding to a strong pituitary signal).
What does a low Luteinising Hormone result mean?
Low or inappropriately-normal LH with low T = secondary hypogonadism (pituitary or hypothalamic). Reversible causes: opioids, obesity, hyperprolactinaemia, anabolic steroid recovery.
Why does Luteinising Hormone matter?
Total T alone can't classify hypogonadism. LH and FSH are the diagnostic pair.
FAQs
- What does high LH mean in men?
- Usually primary hypogonadism — the pituitary is shouting because the testes aren't responding. Klinefelter, prior orchitis, ageing, or testicular damage.
- Can LH be too low?
- Yes — typical in secondary hypogonadism, opioid use, anabolic steroid recovery, and pituitary disorders.
Want Luteinising Hormone interpreted in the context of your full panel? Every FORM bloodwork tier covers it, with an MD walking you through the result.
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