hCG
Human chorionic gonadotropin, Pregnyl, Novarel, Ovidrel
An approved fertility drug that found its real audience among men on testosterone trying not to become infertile, with dose-response trial data behind that exact use.
FDA-approved
FDA-approved for hypogonadotropic hypogonadism in men, prepubertal cryptorchidism, and ovulation induction in women. Use alongside testosterone replacement to preserve fertility is off-label but well documented.
What it is
Human chorionic gonadotropin is a placental hormone that happens to be structurally close enough to luteinising hormone to activate the same receptor. In men that means it acts directly on the Leydig cells in the testes, telling them to produce testosterone locally, exactly as LH would.
That direct action is why it occupies a different position from enclomiphene. Enclomiphene works upstream, at the pituitary, to restart the body's own LH signal. hCG bypasses the pituitary and substitutes for the signal. One restarts the axis, the other replaces a step in it.
The problem it actually solves
Exogenous testosterone suppresses gonadotropins. Without LH reaching the testes, intratesticular testosterone collapses and spermatogenesis stops. Azoospermia occurs in roughly 65% of men on testosterone replacement.
Coviello and colleagues quantified the rescue in 2005. Men given testosterone enanthate plus either saline or hCG at 125, 250 or 500 IU every other day had intratesticular testosterone measured directly by fine needle aspiration. Even the lowest dose, 125 IU every other day, restored intratesticular testosterone substantially in men whose gonadotropins had been suppressed.
Hsieh and colleagues followed with clinical outcomes: men on testosterone plus low-dose hCG maintained semen parameters over months of treatment rather than losing them.
This is unusually good evidence for something used off-label. There is a measured dose-response relationship, a plausible mechanism, and clinical follow-up.
Practical notes
- It does not prevent suppression of the axis, it substitutes for part of it. hCG maintains testicular function during testosterone therapy. It does not keep the pituitary signalling, and it is not a fertility treatment on its own for every cause of infertility.
- More is not better here. Higher hCG doses raise oestradiol through increased aromatisation, which is how people end up adding an aromatase inhibitor to manage a problem they created with dosing. The trial data supports low doses.
- The compounding supply has been unstable. hCG was placed on the FDA's list of substances that may not be compounded under certain conditions, which has periodically disrupted access through compounding pharmacies. Pharmaceutical-grade product remains available by prescription.
- Monitoring is the point. Intratesticular testosterone is not something you can infer from a serum level. If fertility preservation is the goal, semen analysis is the endpoint that actually answers the question.
Side effects and warning signs
Commonly reported
- Injection-site reactions
- Fluid retention
- Gynaecomastia or breast tenderness, since hCG raises intratesticular testosterone and therefore aromatisation
- Acne
- Mood changes
Stop and get medical help
- Signs of a thromboembolic event, which is a documented if uncommon risk with gonadotropin therapy
- Severe pelvic or abdominal pain in women, which can indicate ovarian hyperstimulation
- Precocious puberty signs when used in boys
Sources
From the community
Discussion for this compound concentrates in r/Testosterone and r/trt.
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