Key takeaways:
- Enclomiphene and clomiphene raise testosterone by blocking estrogen's feedback on the brain, which increases the body's own LH and FSH, while hCG raises testosterone by acting directly on the testes as an LH substitute, and a 2018 randomized trial found clomiphene raised total testosterone to 158 ng/dL versus 134 ng/dL with hCG alone (Habous et al., BJU International, 2018).
- In a small case series of 26 hypogonadal men, adding 500 IU of hCG every other day to ongoing testosterone therapy meant no man became azoospermic, and 9 of the 26 went on to conceive with their partner during follow-up (Hsieh et al., Journal of Urology, 2013).
- None of the three options has been shown in a controlled trial to increase pregnancy or live birth rates, and the AUA and ASRM's 2024 Male Infertility Guideline states the evidence for combining hCG with ongoing testosterone therapy specifically is still insufficient, even though it allows the approach.
If you have been told you need more testosterone but you also want to have children, someday or soon, you have probably run into a frustrating catch. Standard testosterone therapy works well for symptoms like low energy and low libido, but it also tends to shut down sperm production almost completely, because the brain reads the extra testosterone in your blood as a sign to stop sending the signal your testes need to keep making both testosterone locally and sperm. Our article on TRT-induced infertility covers why that happens and how often.
Three treatments get discussed as ways around that problem: enclomiphene, clomiphene, and human chorionic gonadotropin, usually shortened to hCG. All three raise testosterone without simply adding it from outside, which is why they can preserve fertility in a way standard testosterone therapy cannot. But they are not the same drug wearing different names, they work through different mechanisms, have different evidence behind them, and fit different men. This article compares them directly: how each one works, what the actual trial data shows, and who is a realistic candidate for which.
What are enclomiphene, clomiphene, and hCG, and why do they matter for male fertility?
All three are prescription treatments used to raise testosterone in men while trying to keep sperm production running, which is the opposite of what standard testosterone replacement therapy does. Clomiphene and enclomiphene belong to a drug class called selective estrogen receptor modulators, or SERMs, which work at the level of the brain. Clomiphene is actually a mixture of two mirror-image molecules, and enclomiphene is simply the more active one of that pair, isolated on its own (Saffati et al., Translational Andrology and Urology, 2024); our full enclomiphene explainer goes deeper on that distinction. hCG is a different type of molecule entirely, a hormone that acts directly on the testes rather than on the brain.
Why this matters is straightforward. A man with low testosterone who also wants to preserve fertility, whether he is thinking about children now or years from now, generally cannot use standard testosterone therapy safely for that goal. These three treatments exist because there is real demand for a way to feel the benefits of adequate testosterone without giving up the ability to have children in the process.
Their regulatory footing is not the same, and it is worth being accurate about this upfront. hCG carries FDA approval for treating hypogonadotropic hypogonadism in men, which includes stimulating testosterone production and spermatogenesis. Clomiphene is FDA-approved only for female infertility, so every use of it in men is off-label, even though that off-label use goes back decades. Enclomiphene has no FDA approval for any indication; its manufacturer's application was declined, and what is available today is prepared by a compounding pharmacy and prescribed off-label. None of this determines which option is more effective, but it is a real difference in how each drug is regulated and monitored.
How does each treatment actually work?
Enclomiphene and clomiphene work by turning up the brain's own hormone signal, while hCG skips the brain and acts directly on the testes. To see why that distinction matters, it helps to picture the chain of command your body uses to make both testosterone and sperm. The hypothalamus, a small region at the base of the brain, sends a pulsing signal to the pituitary gland. The pituitary responds by releasing LH, which travels to the testes and tells specialized cells called Leydig cells to produce testosterone, and FSH, which supports the cells that nurture developing sperm. This whole loop is called the HPG axis. The testosterone that actually drives sperm production is not the number on a blood test, it is the concentration inside the testes themselves, which normally runs 50 to 100 times higher than what circulates in blood.
Specifically, both drugs work at the top of that chain. Estrogen, which men also produce, normally tells the brain when enough hormone is circulating, and the brain dials its signal down in response. These two drugs block that estrogen signal from being read at the hypothalamus and pituitary, so the brain assumes levels are low and pushes harder, sending out more LH and FSH. The testes respond to that stronger signal by making more testosterone on their own, and because the LH and FSH signal never stops, sperm production keeps running.
hCG skips the brain entirely and acts on the last step of the chain. It shares its alpha subunit with LH and binds the same receptor on Leydig cells, functioning as a direct substitute for LH, with the practical advantage of a half-life of about 36 hours compared with LH's roughly 20 to 30 minutes, so a single dose keeps signaling the testes far longer (Lee and Ramasamy, Translational Androl and Urology, 2018). Because hCG stimulates the testes directly, it can raise intratesticular testosterone even in a man whose own pituitary signal has already been switched off, which is exactly the situation of a man currently on testosterone therapy. A randomized study gave 29 healthy men weekly testosterone injections, which normally suppress the body's own hormone signal almost completely, alongside one of several low doses of hCG. Intratesticular testosterone tracked the hCG dose closely: it ended up 25 percent below each man's own baseline at the lowest dose tested, only 7 percent below baseline at a middle dose, and 26 percent above baseline at the highest dose tested, 500 international units every other day (Coviello et al., Journal of Clinical Endocrinology and Metabolism, 2005). In plain terms, the right dose of hCG can hold intratesticular testosterone near normal even while a man is actively taking testosterone that would otherwise shut it down.
What does the research actually show on hCG?
The most direct test of hCG's real-world use came from a small case series of 26 hypogonadal men, average age 35.9, who took testosterone therapy alongside 500 IU of hCG injected every other day. Testosterone therapy on its own is associated with azoospermia, a complete absence of sperm in the ejaculate, in roughly 40 percent of men. In this group, on hCG alongside their testosterone, no man became azoospermic, and 9 of the 26 men went on to conceive a pregnancy with their partner during the follow-up period (Hsieh et al., Journal of Urology, 2013). That is a meaningful, real-world result, and it is also a small study with no comparison group who took testosterone alone for direct contrast, so it shows what is possible rather than a guaranteed outcome.
When hCG is compared head to head against a SERM rather than against testosterone therapy, the picture shifts. A randomized trial of men with hypogonadism assigned to clomiphene, hCG, or a combination found that by the end of the study, total testosterone reached 158 ng/dL on clomiphene alone and 134 ng/dL on hCG alone, a statistically significant difference favoring clomiphene, while combining the two produced 153 ng/dL, not meaningfully different from clomiphene by itself (Habous et al., BJU International, 2018). A 2025 systematic review and meta-analysis pooling 10 randomized trials and 819 patients, which included this comparison among others, reached the same broad conclusion: SERM therapy alone and SERM combined with hCG performed similarly on testosterone, and both outperformed hCG used by itself in this particular dataset (Hohl et al., Archives of Endocrinology and Metabolism, 2025). That does not mean hCG is a weak treatment, it means that for raising testosterone specifically, adding hCG on top of a SERM did not clearly add benefit in this pooled comparison, which matters if you are choosing between a once-daily pill and a more frequent injection.
A separate small retrospective study looked at 28 men who switched from exogenous testosterone to hCG on its own and found no significant change in estradiol and no thromboembolic events over the follow-up period, alongside a meaningful drop in a blood marker called hematocrit that testosterone therapy tends to raise (Rainer et al., Cureus, 2022). It is a small, uncontrolled dataset, but it is a reasonable early signal on tolerability for men transitioning off testosterone onto hCG.
What does the research show on enclomiphene and clomiphene specifically?
The core trial data for enclomiphene comes from a combined analysis of two phase III studies in roughly 256 overweight men with low testosterone. Enclomiphene raised average testosterone from about 205 ng/dL at baseline into the 400s, while sperm concentration rose by 12 to 15 percent. Men given testosterone gel instead saw their testosterone rise too, but their sperm concentration fell by a third to more than half (Kim et al., BJU International, 2016). An earlier phase II trial found the same pattern, with enclomiphene raising testosterone within about two weeks while preserving sperm counts that a topical testosterone gel reduced in the comparison arm (Wiehle et al., Fertility and Sterility, 2014).
The direct comparison between enclomiphene and its parent compound, clomiphene, is more nuanced than marketing for either drug tends to suggest. A study comparing the two found the testosterone increase was not significantly different between them, a median of 166 ng/dL with enclomiphene, but enclomiphene produced a significantly smaller rise in estradiol, the main form of estrogen, than clomiphene did, and significantly fewer side effects like reduced libido, low energy, and mood changes (Saffati et al., Translational Andrology and Urology, 2024). That is a real and reasonable advantage for enclomiphene in terms of tolerability, but it is not evidence that enclomiphene is a more effective fertility treatment than the older, considerably cheaper clomiphene.
What we are more skeptical about
None of these three treatments, enclomiphene, clomiphene, or hCG, has been shown in a randomized trial to increase actual pregnancy or live birth rates. Every study cited above measured testosterone, LH, FSH, or sperm concentration, which are the raw ingredients of fertility, not the outcome couples actually care about. The biological logic connecting preserved sperm counts to a higher chance of conception is reasonable, but it has not been proven to a high standard, and a recent review of this literature explicitly calls for future trials that measure conception and live birth directly rather than only hormones and sperm numbers.
It is also worth being precise about how strongly guidelines actually back these options. The AUA and ASRM's 2024 amended Male Infertility Guideline is direct and strongly worded on one side of this: testosterone should not be prescribed to men who are currently trying to conceive. On the alternatives, the guideline is more cautious, allowing clinicians to use hCG, SERMs, or aromatase inhibitors for men with low testosterone who want to maintain fertility, but at a noticeably weaker level of confidence than the recommendation against testosterone itself, and it states plainly that the evidence specifically supporting combined hCG plus ongoing testosterone therapy for preserving future fertility is still insufficient, despite the encouraging mechanistic and case-series data. A guideline body allowing an option is not the same as a guideline body endorsing it as proven.
hCG carries its own specific caveats. Because it raises testosterone, it also raises the estrogen made from that testosterone through a normal conversion process in the body, which is one plausible reason some men on hCG report breast tenderness or enlargement. The strongest hCG-specific studies here are also small, 26 men in the main fertility-preservation case series and 28 in the safety-focused retrospective study, with no placebo or untreated comparison group in either, and hCG requires an injection two to three times a week rather than a daily pill, which is a real practical and cost burden worth weighing honestly rather than glossing over.
Who is each option most relevant for?
A man already on testosterone therapy who is not ready to stop it but wants to keep the option of having children within the next six to twelve months is the clearest candidate for adding hCG to his existing regimen, at a dose in the range shown to hold intratesticular testosterone near normal, typically around 500 IU every other day, under a clinician's supervision (Coviello et al., Journal of Clinical Endocrinology and Metabolism, 2005; Lee and Ramasamy, Translational Andrology and Urology, 2018).
A man who has not started any testosterone yet, whose low testosterone comes with LH and FSH that are low or in the normal range rather than elevated, a pattern called secondary hypogonadism, is the clearest candidate for enclomiphene or clomiphene instead of ever starting exogenous testosterone in the first place. In that pattern, the testes are capable of responding, they just are not being told to work hard enough, which is exactly what a SERM is designed to fix. Our article on reading your LH level walks through how to tell whether your own pattern looks like this one.
A man who has already stopped testosterone therapy and is actively trying to bring sperm production back up, rather than simply prevent it from falling in the first place, typically moves to a higher and more frequent hCG dose, sometimes with FSH added, under close monitoring; that restoration process is a distinct clinical situation from prevention and deserves its own conversation with a reproductive urologist rather than a self-directed attempt.
What none of these options do
All three drugs depend on the testes still being capable of responding to a stronger signal. In primary testicular failure, where the testes themselves have lost that capacity, for reasons like Klinefelter syndrome or prior chemotherapy, LH is already high because the brain is already pushing as hard as it can, and neither a SERM nor hCG has anything left to stimulate. Testing hormones as a set, not testosterone alone, is what tells you whether you are even a candidate before you start.
None of the three is a self-administered supplement. Each is a prescription treatment that needs a clinician to prescribe it, monitor testosterone, LH, FSH, and estradiol along the way, and confirm the treatment is doing what it is supposed to. And because a full cycle of sperm production takes about 72 days, any of these approaches needs at least 12 weeks before a semen analysis can tell you whether it is working, the same timeline that applies to every fertility intervention we cover.
How does this fit into the bigger picture?
The decision among enclomiphene, clomiphene, and hCG is not one you can make from a testosterone number alone. It depends on whether your low testosterone traces to the brain's signal or the testes themselves, which only shows up when testosterone is measured alongside LH and FSH, and ideally alongside a full semen analysis so you have a real fertility baseline before changing anything. Our guide to what to test before starting TRT covers exactly this panel and why the order you test in matters. If you have already started testosterone therapy and are weighing whether and how to add hCG, our article on recovering fertility after TRT covers what the timeline looks like if you decide to stop instead.
A SwimScore Complete panel measures testosterone, LH, and FSH alongside a full semen analysis and DNA fragmentation, from CLIA-certified labs and against WHO 6th Edition thresholds, in one report you can bring to whichever of these conversations applies to you.
Our take
We know that enclomiphene, clomiphene, and hCG each raise testosterone through a mechanism that does not simply add hormone from outside, and that each one has real trial or case-series evidence behind its ability to preserve or maintain sperm production where standard testosterone therapy would not. We know clomiphene and enclomiphene appear to raise testosterone somewhat more than hCG alone in the head-to-head data available, and that hCG's clearest use case is a man already committed to ongoing testosterone therapy who wants to keep his testes producing sperm in the meantime.
What we do not know, for any of the three, is whether using them actually increases the odds of a pregnancy, since every trial measured hormones and sperm counts rather than conception. That is a real gap, not a technicality, and guideline bodies are honest about it even while allowing these options. The practical path is the same one that applies everywhere in this field: test your full hormone panel and semen parameters before you choose anything, pick the option that matches your specific pattern and your specific goal, give it at least 12 weeks, and measure again before deciding it worked.
FAQ
Is hCG better than enclomiphene or clomiphene for preserving fertility?
Not clearly. In a randomized trial and in a pooled meta-analysis, clomiphene alone and clomiphene combined with hCG raised testosterone somewhat more than hCG used alone, though hCG has the specific advantage of working even when the pituitary signal has already been suppressed by ongoing testosterone therapy (Habous et al., BJU International, 2018; Hohl et al., Archives of Endocrinology and Metabolism, 2025).
Can I take hCG at the same time as testosterone therapy?
Yes, this is one of hCG's main use cases. A case series of 26 men on testosterone therapy plus 500 IU of hCG every other day found no man became azoospermic, compared with an expected azoospermia rate of roughly 40 percent on testosterone alone, though this should be done under a clinician's supervision with monitoring (Hsieh et al., Journal of Urology, 2013).
Is enclomiphene the same as clomiphene?
No. Clomiphene is a mixture of two mirror-image molecules, and enclomiphene is the more biologically active one of that pair isolated on its own. Head-to-head data shows a similar testosterone increase between them, but enclomiphene causes a smaller rise in estradiol and fewer side effects (Saffati et al., Translational Andrology and Urology, 2024).
Do enclomiphene, clomiphene, or hCG improve pregnancy chances?
This has not been proven in a controlled trial for any of the three. The available studies measured testosterone, LH, FSH, and sperm concentration, not actual pregnancy or live birth rates, so the connection to real-world conception odds remains a reasonable but unproven expectation.
Will any of these options work if I already have high LH and FSH?
Generally not. High LH and FSH alongside low testosterone usually means the testes themselves cannot respond to a stronger signal, a pattern called primary hypogonadism, and none of these three treatments can restore function the testes have already lost.
References
- Habous M, Giona S, Tealab A, et al. Clomiphene citrate and human chorionic gonadotropin are both effective in restoring testosterone in hypogonadism: a short-course randomized study. BJU International. 2018;122(5):889-897. https://doi.org/10.1111/bju.14401
- Hsieh TC, Pastuszak AW, Hwang K, Lipshultz LI. Concomitant intramuscular human chorionic gonadotropin preserves spermatogenesis in men undergoing testosterone replacement therapy. Journal of Urology. 2013;189(4):647-650. https://pubmed.ncbi.nlm.nih.gov/23260550/
- Coviello AD, Matsumoto AM, Bremner WJ, et al. Low-dose human chorionic gonadotropin maintains intratesticular testosterone in normal men with testosterone-induced gonadotropin suppression. Journal of Clinical Endocrinology and Metabolism. 2005;90(5):2595-2602. https://pubmed.ncbi.nlm.nih.gov/15713727/
- Lee JA, Ramasamy R. Indications for the use of human chorionic gonadotropic hormone for the management of infertility in hypogonadal men. Translational Andrology and Urology. 2018;7(Suppl 3):S348-S352. https://tau.amegroups.org/article/view/19649/html
- Hohl A, et al. Clomiphene or enclomiphene citrate for the treatment of male hypogonadism: a systematic review and meta-analysis of randomized controlled trials. Archives of Endocrinology and Metabolism. 2025;69(5):e250093. https://pmc.ncbi.nlm.nih.gov/articles/PMC12510335/
- Rainer Q, Pai R, Zucker I, Ramasamy R, Masterson TA. The safety of human chorionic gonadotropin monotherapy among men with previous exogenous testosterone use. Cureus. 2022;14(6):e25826. https://pmc.ncbi.nlm.nih.gov/articles/PMC9271319/
- Kim ED, McCullough A, Kaminetsky J. Oral enclomiphene citrate raises testosterone and preserves sperm counts in obese hypogonadal men, unlike topical testosterone: restoration instead of replacement. BJU International. 2016;117(4):677-685. https://pubmed.ncbi.nlm.nih.gov/27979553/
- Wiehle RD, Fontenot GK, Wike J, et al. Enclomiphene citrate stimulates testosterone production while preventing oligospermia: a randomized phase II clinical trial comparing topical testosterone. Fertility and Sterility. 2014;102(3):720-727. https://pubmed.ncbi.nlm.nih.gov/25044085/
- Saffati G, Kassab J, et al. Safety and efficacy of enclomiphene and clomiphene for hypogonadal men. Translational Andrology and Urology. 2024. https://tau.amegroups.org/article/view/129106/html
- American Urological Association and American Society for Reproductive Medicine. Diagnosis and Treatment of Infertility in Men, AUA and ASRM Guideline. 2020, amended 2024. https://www.auanet.org/guidelines-and-quality/guidelines/male-infertility
Trying to decide whether enclomiphene, clomiphene, or hCG fits your situation? SwimScore Complete measures testosterone, LH, FSH, semen parameters, and DNA fragmentation together from home, from the same CLIA-certified labs fertility clinics use, so you and your clinician can see which pattern you are actually working with.
Fertility clinics and urology practices: if patients are weighing testosterone therapy against a fertility-preserving alternative, a complete baseline panel makes that conversation concrete. See how SwimScore works with clinics on our clinic page.
This article is for general education and is not medical advice. Enclomiphene, clomiphene, and hCG are all prescription treatments, and decisions about starting, combining, or stopping any of them should be made with a urologist, endocrinologist, or fertility specialist who knows your full history.
SwimScore uses CLIA-certified labs for all semen analysis and hormone testing, assessed against WHO 6th Edition clinical thresholds.
