Peptide Schedule
HCG (Human Chorionic Gonadotropin)19 residues (approx.)CPTMTRVLQGVLPALQVVCEach bubble = one amino acid. Size = residue mass. Color = chemical class.Uses closest standard amino acids for non-standard residues.HCG (Human Chorionic Gonadotropin)
Benefits
About HCG (Human Chorionic Gonadotropin)
HCG isn't technically a peptide — it's a glycoprotein hormone produced naturally during pregnancy. But it's become one of the most widely used compounds in TRT and fertility protocols because it mimics luteinizing hormone (LH). When men take exogenous testosterone, the brain stops sending LH signals to the testes, which causes them to shrink and stop producing sperm. HCG fills that gap — it keeps the testes functioning, preserves fertility, and maintains intratesticular testosterone production even while on TRT. The FDA approved HCG decades ago for fertility indications under brand names like Pregnyl, Novarel, and Ovidrel. However, in March 2020, the FDA reclassified HCG as a biologic under the BPCIA, which pulled it from compounding pharmacy shelves overnight. Today, only brand-name pharmaceutical HCG is legally available in the US — a change that significantly increased costs for TRT patients. A key study by Coviello et al. (2005) showed that just 250 IU of HCG every other day was enough to maintain intratesticular testosterone at 25% of baseline in men on exogenous testosterone — compared to near-zero without it. At 500 IU every other day, intratesticular testosterone was maintained at about 7x higher than the suppressed group.
Who Should Consider HCG (Human Chorionic Gonadotropin)
- Men on TRT wanting to preserve fertility
- Men experiencing testicular atrophy from testosterone use
- Couples undergoing fertility treatment
- Men in post-cycle therapy (PCT)
How HCG (Human Chorionic Gonadotropin) Works
HCG binds to the same receptor as luteinizing hormone (LHCGR) on Leydig cells in the testes. This triggers the cAMP signaling cascade that stimulates testosterone synthesis. It also supports Sertoli cell function indirectly, which is needed for spermatogenesis. Because HCG bypasses the hypothalamic-pituitary axis entirely, it can maintain testicular function even when the brain's own LH production is completely shut down by exogenous testosterone. The glycoprotein's larger molecular weight (~36.7 kDa) gives it a much longer half-life than endogenous LH, which is why 2-3 injections per week are enough for steady stimulation.
What to Expect
LH receptor activation begins. Intratesticular testosterone rises. Some men notice improved testicular fullness.
Testicular volume stabilizes or increases. Sperm parameters begin improving.
Full effect on intratesticular testosterone. Semen analysis may show improvement.
Spermatogenesis typically restored. Fertility potential significantly improved vs TRT-only.
Dosing Protocol
| Level | Dose / Injection | Frequency |
|---|---|---|
| Beginner | 250 IU | 3x/week |
| Moderate | 500 IU | 3x/week |
| Aggressive | 1,000 IU | 3x/week |
Note: IMPORTANT: Doses shown are in IU, not mcg. Vial sizes represent 5,000 IU and 10,000 IU. Since March 2020, compounding pharmacies can no longer produce HCG — only brand-name versions (Pregnyl, Novarel, Ovidrel) are available. Use bacteriostatic water for reconstitution.
How to Inject HCG (Human Chorionic Gonadotropin)
Inject subcutaneously into abdominal fat or intramuscularly into deltoid or glute. SC preferred by most TRT clinics. Reconstitute with bacteriostatic water (not sterile water — multi-dose vials need the preservative). Rotate injection sites. Space injections evenly across the week.
Cycling Protocol
Typically used continuously alongside TRT — not cycled. For PCT, 2-4 weeks is common. Doses above 1,500 IU per injection risk Leydig cell desensitization.
Pharmacokinetics
Source: Pregnyl FDA label; confirmed by Rizkallah et al.
Loading the interactive decay curve.
Side Effects
Elevated estradiol is the most common issue — HCG stimulates testosterone production, and some converts to estrogen. An aromatase inhibitor may be needed. Water retention and bloating at higher doses. Gynecomastia risk if estrogen isn't managed. Headache and irritability reported. Leydig cell desensitization possible with chronic high-dose use above 1,500 IU per injection. Injection site pain with IM administration.
Contraindications
- Pregnancy (unless under direct fertility specialist supervision)
- Hormone-sensitive cancers (prostate, breast)
- Precocious puberty
- Known hypersensitivity to HCG
- Androgen-dependent neoplasm
Drug Interactions
- Aromatase inhibitors (commonly co-prescribed to manage estradiol)
- Exogenous testosterone (standard combination in TRT fertility protocols)
- SERMs like clomiphene (sometimes stacked in PCT)
- GnRH agonists/antagonists (opposing mechanisms — avoid combining)
