This tab covers non-surgical (hormonal) therapy for male infertility and how treatment is selected by clinical scenario. The unifying principle: boost endogenous, intratesticular testosterone without exogenous testosterone, which suppresses spermatogenesis.
Medical (Non-Surgical) Therapy
- Selective estrogen receptor modulators (SERMs) — clomiphene, tamoxifen. They antagonise estrogen receptors at the hypothalamus/pituitary, raising GnRH → LH/FSH → testosterone (and sperm counts), with a greater testosterone rise than anastrozole. Clomiphene (25 mg up to 100 mg daily) is the most-used agent for hypogonadism when fertility must be preserved, though it is off-label (not FDA-approved in males); enclomiphene is the side-effect-sparing stereoisomer in development. Consider SERMs for low testosterone with a borderline-high FSH ("lazy pituitary").
- Aromatase inhibitors (anastrozole, letrozole) — block conversion of testosterone to estradiol, useful in men with testosterone deficiency and elevated estradiol (a low T:E ratio <10, as in obesity or Klinefelter); off-label, with a theoretical risk of reduced bone density.
- Gonadotropins — hCG mimics LH to drive Leydig-cell (intratesticular) testosterone; it is FDA-approved for pituitary hypogonadism (e.g. Kallmann) and works best with a pre-treatment testis length >4 cm, often given alone for 3–6 months before adding FSH. FSH alone does not induce spermatogenesis without adequate intratesticular testosterone. hCG can cause gynecomastia in up to one-third (treat with anastrozole); pulsatile GnRH is not approved in the US/Europe.
- Growth hormone (via IGF-1, off-label) and supplements/antioxidants (questionable clinical utility) round out the options.
Treatment Selection
- Do not prescribe testosterone monotherapy to a man interested in current or future fertility — its negative feedback suppresses gonadotropins and spermatogenesis (recovery after stopping takes months, rarely years).
- Hyperprolactinemia — treat the underlying cause.
- Secondary (hypogonadotropic) hypogonadism — deficient LH/FSH. Idiopathic/congenital (Kallmann) responds to exogenous gonadotropins; first-line is hCG (1,500–2,500 IU twice weekly, response proportional to baseline testis size), adding FSH after testosterone normalises. For acquired causes, treat the underlying disorder first; SERMs are an off-label alternative (ineffective if the pituitary itself is damaged, e.g. post-resection).
- Infertile men with low testosterone (low/normal LH) — use AIs, hCG, or SERMs (alone or combined) to raise endogenous testosterone without impairing spermatogenesis: AIs if estradiol is elevated, hCG or SERMs if LH is low/normal; an elevated LH (primary hypogonadism) predicts a limited response.
- Idiopathic infertility — SERMs offer limited benefit relative to ART (IVF gives higher pregnancy rates); an FSH analogue may be considered.
- Non-obstructive azoospermia — optimise spermatogenesis before surgical sperm retrieval, though the data for SERMs/AIs/gonadotropins beforehand are limited.
Self-Test
1. What are the different classes of medications used to treat male infertility? Selective estrogen receptor modulators (clomiphene, tamoxifen), aromatase inhibitors (anastrozole, letrozole), gonadotropins (hCG, FSH, GnRH), and growth hormone.