Definition
What LH measures
Luteinizing hormone is the pituitary signal that triggers ovulation and tells the testes to make testosterone. Timing in the menstrual cycle changes the number sharply.
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HormonesEssentialCompletemIU/mL
LH
The pituitary signal that drives ovulation and testicular testosterone
Illustrative sample band · Synthetic
5.2mIU/mL
0Sample target 1–10 mIU/mL16
Why it matters
How clinicians usually read it
It helps a clinician read whether a low or high sex-hormone result is a gland problem or a pituitary signal problem. Porter and SiPhox both keep it on the broader hormone set.
When it reads low
A lower value can mean
A lower LH can mean the pituitary is quiet, the draw landed in a low-signal part of the cycle, or exogenous hormones are suppressing the axis.
When it reads high
A higher value can mean
A higher LH can mark menopause, PCOS patterns, or primary gonadal failure. Cycle day and medications have to be known first.
Questions for a clinician
Bring the number into a real conversation
01
Where was I in my cycle, or am I on hormones that suppress LH?
02
Does this LH fit my testosterone or estradiol?
03
Should FSH and the LH/FSH ratio be the next read?
Educational boundary
Educational information only. Displayed ranges are illustrative sample bands, not a diagnosis, treatment plan, or substitute for the contracted laboratory report and a qualified clinician.
See it as a sample result
The sample dashboard shows an illustrative reading, target band, and trend for LH.