Evidence explainerMen's Hormones & TRT

TRT and Fertility: hCG, Clomiphene, Enclomiphene and What the AUA Guidelines Allow

Testosterone therapy can shut down sperm production, so AUA guidelines say not to prescribe it to men trying to conceive. They list hCG, SERMs such as clomiphene, and aromatase inhibitors as fertility-sparing options, all on low-grade evidence and mostly off-label.

By Kymata Labs EditorialPublished October 11, 2026Last verified October 11, 2026

Medical review pending. Written by our editorial team from the studies and documents cited below; a credentialed clinician has not reviewed it yet. Educational only, not medical advice.

Key takeaways

  • The AUA testosterone guideline says exogenous testosterone should not be prescribed to men who are currently trying to conceive, a strong recommendation on high-grade evidence [1].
  • The AUA/ASRM male infertility guideline goes further: for men interested in current or future fertility, clinicians should not prescribe testosterone [2].
  • Both guidelines allow aromatase inhibitors, hCG, SERMs (such as clomiphene) or combinations to raise a man's own testosterone, as a conditional recommendation on low-grade evidence [1][2].
  • Of these, only hCG is FDA-approved for use in men, for hypogonadism caused by low pituitary signals [1][3].
  • Adding low-dose hCG to TRT kept semen results stable in a 26-man case series [4], but the infertility guideline calls the evidence for this approach too limited to recommend it [2].

Why testosterone and sperm production clash

Sperm production depends on the pituitary hormones LH and FSH and on a high testosterone level inside the testes. Testosterone taken from outside suppresses LH and FSH, so the testes make less of their own testosterone and less sperm. The AUA notes that weekly testosterone injections cut testosterone inside the testes by 94% within 3 weeks in one study, and that men can become severely oligospermic or azoospermic [1].

Labels carry the same warning: testosterone may lead to azoospermia [5]. That is why the AUA recommends a reproductive health evaluation before treatment in men who are interested in fertility [1].

Already on TRT: how recovery works after stopping

Most men recover sperm production after stopping, but timing varies. In an analysis of 30 contraception studies in 1,549 healthy men, sperm concentration took a median 3.4 months to return to 20 million/mL; 67% recovered within 6 months, 90% within 12 months, 96% within 16 months and all within 24 months [6].

Those figures come from healthy volunteers in contraception trials. For men on testosterone therapy, the AUA/ASRM guideline says recovery can take months or rarely years, and that some men never fully recover their sperm production [2]. The AUA testosterone guideline adds that hCG alone or with SERMs has helped recovery in men with past testosterone or anabolic steroid use, though return of sperm can take up to two years and does not happen for everyone [1].

hCG: standing in for LH

Human chorionic gonadotropin (hCG) acts like LH and tells the testes to make testosterone [1]. It is the only one of the alternatives that is FDA-approved for men: the Novarel label lists selected cases of hypogonadotropic hypogonadism (low testosterone caused by a pituitary deficiency) in males [3].

Used alongside TRT, low-dose hCG aims to keep testosterone inside the testes high enough for sperm production. In a retrospective series of 26 men (mean age 35.9) on testosterone plus hCG, followed for a mean 6.2 months, semen parameters did not change, no man became azoospermic, and 9 contributed to a pregnancy [4].

The AUA/ASRM infertility guideline is cautious: for men who want children further in the future, some studies show that adding hCG alone or in combination preserves sperm production, but it calls the literature too limited to recommend the approach [2].

SERMs: clomiphene and enclomiphene

Selective estrogen receptor modulators (SERMs) are pills that block estrogen's brake on the brain, so the pituitary releases more LH and FSH and the testes make more of their own testosterone [1]. In two randomized trials the AUA cites, sperm concentration was maintained in men on a SERM, similar to placebo, but fell significantly in men on testosterone [1].

Clomiphene is FDA-approved only for ovulation problems in women; its label says there are no adequate, well-controlled studies showing it works for male infertility [7]. Enclomiphene is one of the two isomers that make up clomiphene [8]; its access and prices are covered in enclomiphene online. Our clomiphene for men guide covers the evidence and side effects in detail.

SERMs only work if the testes can respond. The AUA notes that if testosterone stays low while LH is high on a SERM, the problem is likely in the testes and a higher dose is unlikely to help [1].

Aromatase inhibitors

Aromatase inhibitors block the conversion of testosterone to estradiol [1]. In a randomized trial the AUA cites, comparing clomiphene with the aromatase inhibitor anastrozole in infertile men with low testosterone, clomiphene raised testosterone more, anastrozole improved the testosterone-to-estradiol ratio more, and neither changed semen parameters significantly [1].

Because estradiol helps maintain bone density, the AUA says aromatase inhibitors generally should not be used for extended periods [1].

Questions to settle before starting

Three questions shape the choice, and each has a guideline answer to start from.

  • Do you want children now, soon or someday? The AUA/ASRM guideline says testosterone should not be used by men pursuing or planning a family in the near future; men planning paternity further out may be offered it after counseling on its effects and recovery time [2].
  • Has a reproductive health evaluation been done? The AUA recommends one before treatment in men interested in fertility [1], and lists FSH as an optional baseline test for them [1].
  • If an alternative is chosen, how will it be monitored? The AUA recommends checking testosterone no sooner than four weeks after starting clomiphene, hCG or an aromatase inhibitor, and estradiol in all men on aromatase inhibitors [1].

Quick answers

Can I get my partner pregnant while on TRT?

Fertility can drop sharply. Testosterone suppresses sperm production and may cause azoospermia [5], and the AUA says it should not be prescribed to men who are trying to conceive [1].

Does hCG protect fertility on TRT?

It may. A 26-man case series found stable semen results and no azoospermia on testosterone plus low-dose hCG [4], but the AUA/ASRM guideline calls the evidence too limited to recommend this approach [2].

How long after stopping TRT does sperm come back?

In contraception studies of healthy men, the median was 3.4 months, with 90% recovered within a year [6]. The AUA/ASRM guideline warns it can take longer and that some men never fully recover [2].

Is clomiphene FDA-approved for men?

No. Clomiphene is approved for ovulation problems in women, and its label says effectiveness in male infertility has not been shown in adequate studies [7]. Among the alternatives to testosterone, only hCG is FDA-approved for use in men [1].

What do the guidelines recommend instead of TRT for men who want kids?

Both AUA guidelines say clinicians may use aromatase inhibitors, hCG, SERMs or a combination, a conditional recommendation on low-grade evidence [1][2].

More in Men's Hormones & TRT

References

  1. [1]Evaluation and Management of Testosterone Deficiency (2024). American Urological Association, 2024.
  2. [2]Diagnosis and Treatment of Infertility in Men: AUA/ASRM Guideline (amended 2024). American Urological Association, 2024.
  3. [3]Novarel (chorionic gonadotropin) for injection prescribing information. DailyMed, U.S. National Library of Medicine, 2025.
  4. [4]Concomitant intramuscular human chorionic gonadotropin preserves spermatogenesis in men undergoing testosterone replacement therapy. J Urol, 2013. PMID 23260550
  5. [5]AndroGel (testosterone gel) 1.62% prescribing information. DailyMed, U.S. National Library of Medicine, 2025.
  6. [6]Rate, extent, and modifiers of spermatogenic recovery after hormonal male contraception: an integrated analysis. Lancet, 2006. PMID 16650651
  7. [7]Clomid (clomiphene citrate) tablets prescribing information. DailyMed, U.S. National Library of Medicine, 2025.
  8. [8]Oral enclomiphene citrate stimulates the endogenous production of testosterone and sperm counts in men with low testosterone: comparison with testosterone gel. J Sex Med, 2013. PMID 23530575

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