Hormonal Evaluation of the Infertile Male
Interpreting FSH, LH, Testosterone, and Prolactin
Evidence grade 4 of 5, Strong. Read how the Atlas grades evidence.
The written rationale for this grade is still being prepared.
- FDA
- Not applicable (diagnostic evaluation)
Reference only. Not medical advice.
What can go wrong
The main pitfalls are interpretive: testosterone is best measured in the morning and confirmed on a repeat sample before diagnosing hypogonadism, since a single low value can mislead. A normal testosterone does not exclude a spermatogenic problem (FSH and inhibin B are more informative for sperm production). Importantly, a man already on exogenous testosterone will show suppressed LH and FSH regardless of his underlying state, which obscures the evaluation, testosterone usually must be stopped to assess the true axis.
This is something to take to a clinician. The Atlas can tell you what is known about hormonal evaluation of the infertile male in general. It cannot tell you what is happening in your body, and the difference matters most for exactly the symptoms that bring people to this page.
The hormonal evaluation of an infertile man uses a small panel, FSH, LH, total testosterone, and prolactin (with estradiol added in selected cases), to localize the cause along the hypothalamic-pituitary-gonadal axis. The pattern is what matters: high FSH/LH with low testosterone points to primary testicular failure; low FSH/LH with low testosterone points to a central (hypothalamic-pituitary) problem; high prolactin suggests a prolactinoma. Guidelines recommend hormonal testing in men with abnormal semen parameters, low sexual function, or other clinical signs.
The four hormones that localize the problem to the brain, the testis, or in between.
What people take it for
What it is taken for. Approval, where it exists, covers only some of these.
How it works
The hypothalamus releases GnRH, driving pituitary secretion of LH and FSH. LH stimulates Leydig cells to make testosterone; FSH supports Sertoli cells and spermatogenesis. Inhibin B from Sertoli cells feeds back on FSH. Measuring these hormones reveals where the axis is broken: testicular damage removes feedback, so FSH and LH rise (hypergonadotropic); a pituitary or hypothalamic lesion lowers them (hypogonadotropic), which is important because the latter is often treatable with gonadotropin therapy that can restore fertility.
What it does to fertility
Hormonal evaluation is the bridge between the testosterone and fertility worlds. It identifies hypogonadotropic hypogonadism, one of the few male-factor causes that is highly treatable: gonadotropin or GnRH therapy can restore spermatogenesis. It also exposes the TRT-fertility conflict directly, because exogenous testosterone suppresses LH and FSH and must be discontinued to read the true axis. Elevated FSH with small testes signals impaired sperm production and helps set expectations for surgical sperm retrieval.
What people get wrong
Often saidNormal testosterone means fertility is fine
ActuallyTestosterone level says little about sperm production; FSH and inhibin B are more informative, and a man with normal testosterone can be azoospermic.
Often saidYou can assess the hormonal axis while on TRT
ActuallyExogenous testosterone suppresses LH and FSH, masking the underlying state; the axis usually must be evaluated off therapy.
Often saidOne low testosterone reading is a diagnosis
ActuallyTestosterone varies and is highest in the morning; a low value should be confirmed on a repeat morning sample before diagnosing hypogonadism.
Who profits, and who pushes back
Nobody is named here yet, because we have not done that work on this entry. Read that as unfinished. Somebody almost certainly sells this, and somebody almost certainly disputes it. Assume both until we have checked.
At a glance
- Core panel
- FSH, LH, total testosterone, prolactin
- Primary testicular failure
- High FSH/LH, low testosterone
- Secondary (central) hypogonadism
- Low/normal FSH/LH, low testosterone
- FSH and spermatogenesis
- Elevated FSH suggests impaired sperm production
- High prolactin
- Suggests prolactinoma; suppresses GnRH
- Recommended sampling
- Morning, fasting where possible; confirm low testosterone on repeat
What this entry does not yet cover
What follows is unfinished work on our side, not a finding about Hormonal Evaluation of the Infertile Male. A short entry is not a safe entry.
- Timeline. We have not built the dated record of research and regulatory events.
- Cost and market. We have not documented what it sells for or who sells it.
- Supply chain. We have not mapped where it is made.
- Who uses it. We have not documented the user groups.
- What could change. No forward-looking summary yet.
- How it compares. We have not set it against the alternatives.
- Children and teenagers. We have not checked what is known about younger people.
- Where we land. We have not taken a position on this yet.
Sources
The studies below are named and described, but not linked. You cannot open them from here and check our reading against them, which means this page is our summary of the literature rather than a document you can verify. Weigh it accordingly until the links exist.
The studies that matter
AUA/ASRM Male Infertility Guideline2021
Recommends hormonal evaluation (at least FSH and total testosterone) in men with abnormal semen parameters or clinical signs of hormonal abnormality
Sigman & Jarow, FSH and testicular volume1997
Showed FSH and testicular volume help distinguish obstructive from non-obstructive azoospermia
Endocrine Society and EAU andrology guidanceVarious
Standardized the FSH/LH/testosterone/prolactin pattern interpretation for male infertility