HCG
Also known as · Human chorionic gonadotropin · Pregnyl · Novarel
- EvidenceApproved
- CategoryGonadotropin
- RouteIM / subQ
- Half-life~24–36 h (biphasic)
01 / Dosing schedule
Cited dosing
The FDA-approved schedule for hypogonadotropic hypogonadism in males is 500–1,000 USP units three times weekly for three weeks, then twice weekly for three weeks. The Coviello 2005 dose-response trial established that 250 IU every other day preserves intratesticular testosterone in men on suppressive TRT.
Pregnyl — male hypogonadotropic hypogonadism
| Phase | Dose & frequency |
|---|---|
| Weeks 1–3 | 500–1,000 IU IM three times weekly |
| Weeks 4–6 | Same dose reduced to twice weekly |
| Alternate schedule | 4,000 IU IM three times weekly for 6–9 months, then 2,000 IU IM three times weekly for 3 months |
| Route (label) | Intramuscular only |
Source · FDA label — Pregnyl (2023) ↗
TRT-adjunct — intratesticular-testosterone preservation
| Phase | Dose & frequency |
|---|---|
| 125 IU every other day | −25% change in intratesticular testosterone vs baseline |
| 250 IU every other day | −7% — near-eugonadal preservation |
| 500 IU every other day | +26% — supraphysiologic |
| Route in trial | Subcutaneous |
Source · Coviello AD et al. JCEM 2005 — low-dose hCG maintenance of ITT ↗
Source indication · Selected cases of hypogonadotropic hypogonadism in males (Pregnyl label).
- Injection frequency
- Two to three times weekly (or every other day for TRT adjunct).
- Injection sites
- IM: gluteal or deltoid muscle (label). Subcutaneous is used in TRT-adjunct practice.
02 / Reconstitution
Reconstitution reference
Pregnyl is supplied as 10,000 USP units of sterile dried powder in a multi-dose vial with a diluent. Reconstitute the entire diluent volume into the powder vial and agitate gently. Reconstituted solution is stable for 60 days refrigerated. At 10,000 IU in 10 mL diluent = 1,000 IU/mL: a 500 IU dose is 0.5 mL = 50 units on a U‑100 syringe.
03 / Overview
Protocol overview
HCG is a heterodimeric glycoprotein hormone that binds the LH receptor. In men it stimulates Leydig-cell testosterone production; in women it triggers ovulation and supports the corpus luteum.
The FDA-labeled hypogonadism schedule is decades old and reflects standalone HCG monotherapy. Modern TRT-adjunct practice uses lower every-other-day doses derived from the Coviello 2005 dose-response trial.
Coviello and colleagues established that 250 IU every other day nearly fully preserves intratesticular testosterone in men on 200 mg weekly testosterone enanthate. This is the reference dose-response for the fertility-preservation goal.
The Pregnyl label lists intramuscular administration only; subcutaneous injection is common in current TRT practice and was the route used in the Coviello study.
04 / References