FSH, LH and prolactin are not “male fertility scores”; they are signalling hormones that help identify where a reproductive or testosterone problem may be occurring. LH stimulates the testes to produce testosterone, while FSH supports sperm production through Sertoli cells. Prolactin is a pituitary hormone that, when markedly elevated, can suppress LH/FSH and reduce testosterone and sexual function. The most useful interpretation comes from the pattern of FSH/LH together with morning testosterone, semen analysis and the clinical examination.

What FSH means

FSH is produced by the pituitary and acts mainly on Sertoli cells involved in spermatogenesis. A clearly elevated FSH in a man with low sperm production suggests impaired testicular sperm-producing tissue. However, a normal FSH does not guarantee normal spermatogenesis and can be seen in obstructive azoospermia or milder production disorders.

What LH means

LH stimulates Leydig cells in the testes to make testosterone. Low testosterone with high LH suggests primary testicular failure. Low testosterone with low or inappropriately normal LH suggests secondary hypogonadism from hypothalamic/pituitary disease or functional suppression related to obesity, illness, medicines or prior androgen use.

What prolactin means

Mild prolactin elevations can occur from stress, poor sleep, exercise, nipple stimulation, hypothyroidism and several medicines. A clearly or persistently high value should be repeated under appropriate conditions and investigated. Marked hyperprolactinaemia can be associated with pituitary adenoma and may cause low libido, erectile dysfunction, infertility and low testosterone.

Useful hormone patterns

• Low testosterone + high LH/FSH: primary testicular failure.
• Low testosterone + low/normal LH/FSH: secondary or functional hypogonadism.
• Azoospermia + high FSH: strongly suggests impaired sperm production, though the complete evaluation still matters.
• Azoospermia + normal FSH and normal testicular size: obstruction becomes more plausible but is not proven.
• Low testosterone + high prolactin: evaluate medicines, thyroid status and pituitary causes as appropriate.

Medicines and exposures that can alter results

• Testosterone or anabolic steroids suppress LH and FSH.
• Opioids can suppress the hypothalamic-pituitary-gonadal axis.
• Some antipsychotics and anti-nausea medicines can raise prolactin.
• Severe illness, obesity and substantial calorie restriction can alter gonadotropin/testosterone patterns.

When pituitary imaging may be considered

MRI is not needed for every mild prolactin elevation or every low testosterone result. It is considered when prolactin is persistently and significantly elevated, there are headaches/visual symptoms, or secondary hypogonadism is severe or otherwise unexplained. The exact threshold and work-up depend on the clinical pattern.

Fertility-specific interpretation

In infertility, hormones are interpreted with semen analysis and testicular examination. Severe oligozoospermia or azoospermia may require genetic testing and specialist evaluation. Giving testosterone to a man who wants fertility can worsen the semen result by suppressing gonadotropins.

FSH can be useful even when testosterone is normal

A man can have normal testosterone production but impaired sperm production because Leydig-cell and seminiferous-tubule function are not identical. In severe oligozoospermia or azoospermia, FSH therefore adds information even when testosterone is within range. However, neither normal nor high FSH can tell exactly whether retrievable sperm will be found; that decision may require genetics, testicular examination and fertility-specialist assessment.

How to repeat an unexpected hormone result

Mild abnormalities are often confirmed before extensive imaging. Prolactin can be repeated after a calm rest period and with review of medicines; testosterone should be repeated in the morning. If biotin or other supplements can interfere with a particular laboratory assay, the laboratory/doctor may advise holding them before repeat testing.

Very high prolactin, severe secondary hypogonadism or neurological symptoms deserve quicker assessment. The magnitude of the abnormality matters: a prolactin just above the upper limit has a very different differential diagnosis from a value many times above normal.

Pattern recognition is more useful than reading each hormone separately

Low testosterone with high LH/FSH points toward primary testicular dysfunction. Low testosterone with low or inappropriately normal LH/FSH suggests secondary hypogonadism and may require review of obesity, systemic illness, medicines, prolactin and pituitary causes. Markedly raised prolactin deserves confirmation and investigation rather than automatic treatment.

In infertility, a high FSH often suggests impaired sperm production, but it does not measure the number of sperm present inside the testis and does not by itself prove that sperm retrieval is impossible. Hormones guide the next question; they rarely provide the whole answer.

When prolactin needs more than a repeat blood test

Mild prolactin elevation is commonly caused by stress, recent exercise, sex, sleep, venepuncture difficulty and medicines such as antipsychotics or some antiemetics. A clearly or repeatedly elevated result should be interpreted with symptoms such as low libido, erectile dysfunction, infertility, headaches or visual symptoms and with the medication list.

Macroprolactin and assay effects can occasionally complicate interpretation. Pituitary MRI is therefore not ordered simply because prolactin is a few points above the laboratory range; it is considered when the elevation is persistent, clinically significant or accompanied by a hormone pattern or symptoms suggesting pituitary disease.

What to bring for consultation

• Morning total testosterone values.
• FSH, LH and prolactin with laboratory ranges.
• Semen analyses.
• Scrotal ultrasound if already performed.
• Medication list including psychiatric drugs, opioids, testosterone, fertility injections and supplements.

FAQs

Related reading

• Testosterone Report Explained
• Semen Analysis Report Explained
• Scrotal Ultrasound Report Explained
• Urologist in Latur

References

• European Association of Urology. EAU Guidelines on Sexual and Reproductive Health: Male Hypogonadism. 2026 https://uroweb.org/guidelines/sexual-and-reproductive-health/chapter/male-hypogonadism
• American Urological Association/American Society for Reproductive Medicine. Diagnosis and Treatment of Infertility in Men: AUA/ASRM Guideline (2020; amended 2024) https://www.auanet.org/guidelines-and-quality/guidelines/male-infertility
• Bhasin S, Brito JP, Cunningham GR, et al. Testosterone Therapy in Men With Hypogonadism: An Endocrine Society Clinical Practice Guideline. J Clin Endocrinol Metab. 2018;103(5):1715-1744. doi:10.1210/jc.2018-00229.