When a man’s semen analysis shows a problem — low count, poor motility, no sperm — the next investigation is almost always a hormone blood test. But most men (and even some of their referring doctors) are unsure what the results mean. Dr. Sonu Balhara, IVF & Fertility Expert at ART Fertility Clinics, Gurugram, explains the three key male reproductive hormones — FSH, LH, and testosterone — what they do, what abnormal levels mean, and one critical warning about testosterone therapy.
The Three Hormones That Control Male Fertility
FSH — Follicle Stimulating Hormone
In men, FSH is produced by the pituitary gland and travels to the testes where it stimulates spermatogenesis — the production of sperm. It acts on Sertoli cells, which are the “nursing cells” that support developing sperm.
Reference ranges vary between laboratories. A 2018 study (Urology, 2018) found that FSH upper limits of normal across laboratories ranged from 7.9 to 20.0 mIU/mL — a wide variation that makes cross-laboratory interpretation difficult. The clinical rule of thumb: an FSH level more than twice the upper limit of normal is a strong indicator of primary testicular failure — the testes are not producing sperm, and the pituitary is signalling urgently by releasing more FSH.
LH — Luteinising Hormone
LH is also produced by the pituitary gland. In men, it stimulates the Leydig cells of the testes to produce testosterone. LH and FSH work together: LH controls testosterone production, FSH controls sperm production.
Testosterone — Total and Free
Testosterone is the primary male sex hormone, produced by the Leydig cells under LH stimulation. Normal total testosterone in adult men is approximately 300–1000 ng/dL (varies by laboratory). Testosterone is essential for spermatogenesis — but high testosterone from external sources can paradoxically shut down sperm production entirely.
What Does an Elevated FSH Mean?
High FSH in a man means the pituitary is working hard to stimulate a testes that is struggling to respond. It indicates:
- Reduced or absent sperm production (oligospermia or azoospermia)
- Damage to the testicular tubules (from infection, prior chemotherapy, radiation, undescended testes, varicocele, or genetic causes)
- Primary hypogonadism — the testicular failure is at the testicular level, not the pituitary
Very high FSH (>2–3x normal) in a man with azoospermia is a significant predictor of non-obstructive azoospermia, where sperm production has been severely impaired. Surgical sperm retrieval (TESA) may still be attempted, but success rates are lower.
What Does a Low FSH Mean?
Low FSH (along with low LH and low testosterone) suggests the problem is in the brain, not the testes — hypogonadotrophic hypogonadism. The pituitary is not sending the signal. Causes include:
- Kallmann syndrome (a genetic condition with absent FSH/LH)
- Pituitary tumour (prolactinoma)
- Significant weight loss, extreme exercise, or stress
- Anabolic steroid use (shuts down the pituitary-gonadal axis)
This is treatable. Gonadotrophin injections (FSH + hCG/LH) can successfully stimulate the testes to produce sperm in many of these men.
⚠️ The Critical Warning About Testosterone Therapy
This is one of the most important points in male fertility medicine. Testosterone replacement therapy (TRT) — whether by injection, gel, or pellet — is used by many men for fatigue, low libido, or “low T.” It raises circulating testosterone. But it does so by switching off the pituitary signals (FSH and LH). Without FSH and LH stimulation, the testes stop producing sperm almost entirely.
The AUA/ASRM Male Infertility Guidelines (2024) are unambiguous: testosterone therapy is CONTRAINDICATED in men who wish to father children. Men on TRT may be severely oligospermic or azoospermic as a direct result. This is often reversible after stopping TRT, but recovery can take 6–18 months and is not guaranteed.
Dr. Sonu Balhara routinely asks about TRT use — including supplements marketed for “testosterone support” — at first consultation. If you or your partner is on any testosterone-containing product, this must be disclosed before fertility investigations begin.
Interpreting the Complete Hormone Panel
A full male hormone panel typically includes: FSH, LH, total testosterone, prolactin, and sometimes thyroid function. Patterns to understand:
- High FSH + high LH + low testosterone → primary testicular failure
- Low FSH + low LH + low testosterone → secondary (pituitary/hypothalamic) failure — treatable with gonadotrophins
- Normal FSH + azoospermia → obstructive azoospermia likely — surgical retrieval usually successful
- High prolactin → pituitary tumour or medication effect — must be investigated and treated
Treatment Options Based on Hormone Profile
- Hypogonadotrophic hypogonadism: hCG + FSH injections can stimulate sperm production
- Elevated prolactin: cabergoline (dopamine agonist) normalises prolactin and often restores FSH/LH
- Primary testicular failure with some sperm: IVF with ICSI; surgical retrieval (TESA/PESA) if azoospermic
- Post-TRT recovery: stop testosterone, wait for natural recovery; clomiphene or hCG can accelerate this
Conclusion
Male hormone tests are not just numbers — they tell a clinical story about where in the reproductive axis the problem lies and, critically, whether it is treatable. Dr. Sonu Balhara evaluates both partners at the first consultation at ART Fertility Clinics, Gurugram. A man’s hormone profile is an essential part of that assessment — not an afterthought.
To book a couple’s fertility assessment with Dr. Sonu Balhara, contact ART Fertility Clinics, Sector 38, Gurugram or her personal clinic in Greenwood City, Sector 46.
Dr. Sonu Balhara | IVF & Fertility Expert | | +91 9811409586 | sonubalharaivf.com
