hCG on TRT: Fertility, Testicular Size and the Evidence

Creator: Peptide Me Editorial Team
Published: 2026-10-12

Testosterone therapy works by replacing a hormone the testes normally make. It also switches off the signal that keeps them making sperm. hCG is the most-studied way to send that signal back, but the evidence is thinner than its popularity suggests.

PMWritten byPeptide Me Editorial Team9 min read · Updated Oct 2026 · Reviewed against 11 sources

TL;DR

Injected testosterone suppresses LH and FSH, testosterone inside the testes falls sharply, and sperm production drops. In a WHO study, 65% of men on 200 mg testosterone enanthate a week had no sperm in the ejaculate within six months.
hCG acts like LH on the testes. In a small randomized study of men on testosterone, 250 IU every other day kept intratesticular testosterone within 7% of baseline, and 500 IU pushed it above baseline. In a retrospective series of 26 men on TRT plus 500 IU hCG every other day, none became azoospermic.
The AUA says clinicians may use hCG, SERMs, aromatase inhibitors or a combination to maintain fertility in men with testosterone deficiency. It is a conditional recommendation with Grade C evidence. Using hCG together with TRT is not an FDA-labeled indication.
Since March 23, 2020, hCG has been regulated in the US as a biological product. Biologics are not eligible for the compounding exemptions, so compounded hCG no longer has a legal pathway. Controlled trials of hCG alongside TRT, including on testicular size, are still missing.

Short answer: hCG (human chorionic gonadotropin) is sometimes added to testosterone therapy because it mimics luteinizing hormone. That keeps the testes producing their own testosterone and, in the studies available, sperm, while TRT keeps blood levels up.^5,6 The AUA lists hCG among options clinicians may use in men who want to keep fertility, but rates the evidence as Grade C.² Pairing hCG with TRT is not an FDA-labeled use.⁷ Since March 2020, hCG has been regulated in the US as a biological product, which closed the legal path for compounded versions.⁸ The best supporting data are a three-week randomized study of intratesticular testosterone and a retrospective series of 26 men. No large controlled trial has tested fertility or testicular size on TRT plus hCG.

This guide covers why TRT affects fertility, what the hCG studies measured, what guidelines and the FDA say, and the questions the evidence has not answered. For the broader list of TRT side effects see TRT side effects. For an alternative that avoids exogenous testosterone altogether, see TRT vs enclomiphene.

Why TRT suppresses sperm production

The testes do two jobs, under two signals from the pituitary. Luteinizing hormone (LH) drives the Leydig cells to make testosterone. Follicle-stimulating hormone (FSH), together with a very high concentration of testosterone inside the testis, supports sperm production. When testosterone is injected, the pituitary reads the high blood level and turns LH down; at large doses FSH falls too, and sperm production is suppressed.¹⁰ Intratesticular testosterone normally runs far above the blood level, and the testis needs that concentration.⁵

The effect on the testis is large. In a study of healthy men given 200 mg of testosterone enanthate weekly for three weeks, LH and FSH fell to 5% and 3% of baseline. Intratesticular testosterone, measured directly from testicular fluid, dropped by 94%, from 1,234 to 72 nmol/L.⁵ At baseline, blood testosterone in those men was only about 1.2% of the level inside the testis.⁵ That gap explains why a normal blood level on TRT does not protect sperm production.

The clinical result is well documented. In the World Health Organization's contraception study, 271 healthy men received 200 mg testosterone enanthate weekly, and 65% became azoospermic within six months.³ The Endocrine Society states that testosterone therapy suppresses spermatogenesis. It recommends against TRT in men planning fertility in the near term.¹ The AUA's recommendation against prescribing testosterone to men who are trying to conceive is graded Strong, on Grade A evidence.²

What hCG does

hCG is a hormone made in pregnancy that binds the same receptor as LH. Injected, it stimulates the Leydig cells directly and skips the suppressed pituitary signal. The testes keep making testosterone locally while TRT supplies the blood level. It does not replace FSH. In US labeling, hCG is approved for prepubertal cryptorchidism, selected cases of hypogonadotropic hypogonadism (pituitary-caused) in males, and ovulation induction in women.⁷ Use alongside TRT is off-label.

What the studies of hCG with TRT show

Study	Who and what	Main finding	Limits
Coviello 2005, randomized⁵	29 healthy men; testosterone enanthate 200 mg weekly plus placebo or hCG 125, 250 or 500 IU every other day, 3 weeks	Intratesticular T fell 94% on placebo; 7% below baseline on 250 IU; 26% above baseline on 500 IU	3 weeks; measured hormone levels, not sperm or fertility
Hsieh 2013, retrospective⁶	26 hypogonadal men, mean age 35.9; weekly injections (19) or gel (7) plus hCG 500 IU IM every other day; mean follow-up 6.2 months	No change in semen parameters; no man became azoospermic; 9 of 26 contributed to a pregnancy	No control group; small; chart review
Hochu 2025, review⁹	Narrative review of fertility-sparing approaches	Concludes low-dose hCG sustains intratesticular testosterone and spermatogenesis	Summarizes the same small studies; calls for larger long-term trials

The dose-finding study

Coviello and colleagues gave 29 men with normal reproductive function 200 mg of testosterone enanthate weekly for three weeks and randomized them to saline or one of three hCG doses. Intratesticular testosterone rose in a straight line with the hCG dose. It ended 25% below baseline at 125 IU, 7% below at 250 IU and 26% above at 500 IU, compared with a 94% fall on placebo.⁵ The study shows that relatively small hCG doses can hold intratesticular testosterone in the normal range. It was too short, at three weeks, to show anything about sperm counts.

The clinical series

Hsieh and colleagues reviewed the records of 26 hypogonadal men, average age 35.9, who received TRT together with 500 IU of hCG intramuscularly every other day. Nineteen used weekly injections and seven used gel. Mean blood testosterone went from 207 to 1,055 ng/dL on treatment. Semen parameters did not change over follow-up, which averaged 6.2 months, and no man became azoospermic. Nine of the 26 contributed to a pregnancy with their partner.⁶

◑ Limited human dataThe Hsieh series has no comparison group of men on TRT alone, and it looked back at charts rather than following a planned protocol. Mean on-treatment testosterone was about 1,055 ng/dL, well above the guideline target range. The results suggest hCG can preserve semen parameters. They do not show how often it succeeds or which men it fails.

Testicular size

Shrinking testes are a common complaint on TRT and a common reason men ask about hCG. The Depo-Testosterone label lists testicular atrophy, subfertility and infertility among reactions reported in men, in its section on abuse and misuse.¹⁰ Gonadotropin stimulation can increase testicular volume. In 50 men with hypogonadotropic hypogonadism treated with hCG and then hCG plus recombinant FSH, median testicular volume rose from 4.0 to 9.0 mL. Sperm appeared in 82%.¹¹

Those men were not on TRT, and they received FSH as well. We did not find a controlled trial that measured testicular volume in men on TRT plus hCG versus TRT alone. The idea that hCG keeps testicular size on TRT follows from the physiology and from clinical experience. It has not been quantified in a trial.

What the guidelines say

The AUA guideline's Statement 27 says clinicians may use aromatase inhibitors, hCG, selective estrogen receptor modulators, or a combination in men with testosterone deficiency who want to maintain fertility. It is a Conditional Recommendation with Grade C evidence. The guideline adds that of these agents, only hCG is FDA-approved for use in males.²

The Endocrine Society guideline does not recommend hCG co-therapy as a routine add-on. It advises against TRT for men wanting fertility soon, suggests sperm banking for men unsure about future children, and notes that a semen analysis before starting can show whether contraception is still needed. It also notes that, in uncontrolled studies, gonadotropin therapy has restarted sperm production in men with hypogonadotropic hypogonadism who had been on TRT.¹

Regulatory and compounding status in the US

hCG's legal category changed in 2020. The Biologics Price Competition and Innovation Act required that on March 23, 2020, approved drug applications for certain protein products be deemed biologics licenses. FDA's list of products that transitioned includes chorionic gonadotropin.⁸ In a 2021 letter to the National Association of Boards of Pharmacy, FDA explained what that means for pharmacies. Biological products are not eligible for the compounding exemptions in sections 503A and 503B of the Food, Drug, and Cosmetic Act, and federal law provides no legal pathway for marketing a biologic prepared outside an approved license.⁸

In practice, compounded hCG from 503A pharmacies or 503B outsourcing facilities no longer has a legal basis. hCG for human use in the US means an FDA-licensed product, prescribed by a clinician. The labeled products are for intramuscular use, and their listed adverse reactions include headache, irritability, restlessness, depression, fatigue, edema, gynecomastia and injection-site pain.⁷ The label also states that hCG has not been shown to be effective for weight loss.⁷

hCG alongside TRT vs other fertility options

Approach	What it does	Evidence and status
TRT alone	Restores blood testosterone; suppresses LH, FSH and sperm production	Not recommended for men trying to conceive^1,2
TRT plus hCG	Replaces the LH signal to the testes during TRT	Small studies; AUA conditional, Grade C; off-label^2,5,6
Stopping TRT and waiting	Lets the pituitary signal return	In healthy men after hormonal contraception: 67% recovered within 6 months, 90% within 12, 100% within 24⁴
SERMs such as enclomiphene or clomiphene	Raise the body's own LH and FSH instead of replacing testosterone	Neither FDA-approved for male hypogonadism; see TRT vs enclomiphene²
Sperm banking before TRT	Stores sperm before suppression starts	Suggested by the Endocrine Society for men unsure about future children¹

The recovery figures come from a pooled analysis of 1,549 healthy men in 30 hormonal contraception studies. Recovery was slower after longer treatment and after longer-acting testosterone preparations.⁴ Men with hypogonadism start from lower function, and many have been on TRT for years, so those timelines are a best case, not a forecast.

What is still unknown

How often hCG co-therapy preserves fertility. The only clinical series has 26 men and no control arm.⁶
Whether hCG maintains testicular volume on TRT. No controlled trial of men on TRT has measured it.
The right dose. The dose-response data come from a three-week study in healthy men.⁵
Whether hCG added after years of TRT works as well as hCG started at the same time as TRT.
Long-term effects of adding hCG on estradiol, hematocrit and symptoms. These have not been studied in controlled trials of co-therapy.
Whether FSH also needs replacing for some men. hCG replaces only the LH signal.

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Questions to raise with your prescriber

If children are a possibility, bring it up before the first injection. A semen analysis beforehand gives a baseline, and sperm banking is an option the Endocrine Society mentions for men who are uncertain.¹ If you are already on TRT and want to conceive, ask whether stopping, switching to a non-testosterone option, or adding hCG fits your situation. Ask how semen will be monitored. Keep a record of the dates you started TRT and any hCG, since how long you were on testosterone affects how quickly sperm counts come back.⁴

⚠︎Educational information only — not medical advice. Testosterone is a prescription medication; discuss any route or dose change with a licensed clinician.

FAQ

The available evidence suggests it can. In a retrospective series of 26 men on TRT plus 500 IU hCG every other day, semen parameters did not change and none became azoospermic, and 9 contributed to a pregnancy. There was no comparison group, and no large controlled trial exists. The AUA rates the evidence as Grade C.

It is plausible but not proven. hCG keeps the testes producing testosterone, and gonadotropin therapy increases testicular volume in men with hypogonadotropic hypogonadism. No controlled trial has measured testicular size in men on TRT plus hCG against TRT alone.

No. hCG is FDA-approved in males for prepubertal cryptorchidism and selected cases of hypogonadotropic hypogonadism. Using it together with testosterone therapy is off-label. The AUA notes that among fertility-sparing agents, only hCG is FDA-approved for use in males at all.

No legal pathway exists. On March 23, 2020, hCG became regulated as a biological product, and FDA has stated that biologics are not eligible for the compounding exemptions under sections 503A and 503B. hCG for human use now means an FDA-licensed product.

In a pooled analysis of 1,549 healthy men after hormonal contraception, 67% recovered to 20 million/mL within 6 months, 90% within 12 months and 100% within 24 months. Recovery was slower after longer use and longer-acting preparations. Men with hypogonadism may take longer.

References

Primary sources — PubMed / NEJM / The Lancet.

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. https://academic.oup.com/jcem/article/103/5/1715/4939465
Mulhall JP, Trost LW, Brannigan RE, et al. Evaluation and Management of Testosterone Deficiency: AUA Guideline. J Urol. 2018;200(2):423-432. https://www.auanet.org/documents/Guidelines/PDF/Testosterone-Deficiency-JU.pdf
World Health Organization Task Force on Methods for the Regulation of Male Fertility. Contraceptive efficacy of testosterone-induced azoospermia in normal men. Lancet. 1990;336(8721):955-959. https://pubmed.ncbi.nlm.nih.gov/1977002/
Liu PY, Swerdloff RS, Christenson PD, Handelsman DJ, Wang C; Hormonal Male Contraception Summit Group. Rate, extent, and modifiers of spermatogenic recovery after hormonal male contraception: an integrated analysis. Lancet. 2006;367(9520):1412-1420. https://pubmed.ncbi.nlm.nih.gov/16650651/
Coviello AD, Matsumoto AM, Bremner WJ, et al. Low-dose human chorionic gonadotropin maintains intratesticular testosterone in normal men with testosterone-induced gonadotropin suppression. J Clin Endocrinol Metab. 2005;90(5):2595-2602. https://pubmed.ncbi.nlm.nih.gov/15713727/
Hsieh TC, Pastuszak AW, Hwang K, Lipshultz LI. Concomitant intramuscular human chorionic gonadotropin preserves spermatogenesis in men undergoing testosterone replacement therapy. J Urol. 2013;189(2):647-650. https://pubmed.ncbi.nlm.nih.gov/23260550/
DailyMed. CHORIONIC GONADOTROPIN kit (Fresenius Kabi USA) — Prescribing Information. U.S. National Library of Medicine. https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=f93b2baa-03ac-4650-b35a-20b818d712d6
U.S. Food and Drug Administration, Office of Compounding Quality and Compliance. Letter to the National Association of Boards of Pharmacy on biological products prepared outside the scope of an approved BLA. May 13, 2021. https://nabp.pharmacy/wp-content/uploads/2021/05/NABP-Compounded-Biologics-Final.pdf
Hochu G, Geyer-Kim I, Kim E. Preserving spermatogenesis in testosterone deficiency: innovations in replacement and stimulatory therapies. Transl Androl Urol. 2025;14(12):3975-3987. https://pmc.ncbi.nlm.nih.gov/articles/PMC12779434/
DailyMed. DEPO-TESTOSTERONE (testosterone cypionate) injection, solution — Prescribing Information. U.S. National Library of Medicine. https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=cfbb53d4-b868-4a28-8436-f9112eb01c39
Cho MC, Lee H, Kim SW. Induction of Spermatogenesis and Its Predictors in Men with Prepubertal-Onset Hypogonadotropic Hypogonadism Undergoing Gonadotropin Therapy. World J Mens Health. 2025;43(4):992-1001. https://pmc.ncbi.nlm.nih.gov/articles/PMC12505474/