hCG
Endogenous LH analogue — FDA-approved for fertility. Used clinically to maintain testicular function and spermatogenesis during TRT.
Research facts
| Half-life | ~24–36 hours |
|---|---|
| Route | SubQ / IM |
| Typical dose | 250–500 IU (TRT adjunct) / 5,000–10,000 IU (fertility) |
| Frequency | 2–3× weekly (TRT adjunct) / Per fertility protocol |
| Solvent | Bacteriostatic water |
| pH | 5.0–7.5 |
| Stability | 30 days at +4°C after reconstitution |
Mechanism of action
Human chorionic gonadotropin is a glycoprotein hormone structurally homologous to LH (shares the LH receptor). Produced by the placenta during pregnancy, it binds the LH/hCG receptor on testicular Leydig cells to drive testosterone production, and on ovarian granulosa cells for ovulation. In men on TRT (testosterone replacement therapy), exogenous testosterone suppresses LH secretion, causing testicular atrophy and impaired spermatogenesis. Low-dose hCG (250–500 IU, 2–3×/week) substitutes for the suppressed LH signal, maintaining intratesticular testosterone, testicular volume, and spermatogenesis. FDA-approved for fertility indications in men and women.
Documented effects (research-model)
- FDA-approved fertility treatment in men and women
- Preserves testicular volume and spermatogenesis during TRT
- Restores HPG axis function post-AAS use
- Intratesticular testosterone maintenance (essential for fertility)
- Ovulation induction in anovulatory women (with FSH)
- Robust human safety and efficacy data across decades
Research protocols
| Protocol | Dose | Frequency | Cycle | Vial |
|---|---|---|---|---|
| TRT Adjunct | 250–500 IU SubQ | 2–3× weekly (concurrent with TRT) | Concurrent with TRT or during restart | 5000 IU / 1mL BAC water |
| HPG Restart | 500–1000 IU 3×/week | 3× weekly × 4–6 weeks then taper | 6–8 weeks | 5000 IU / 1mL BAC water |
Research context only. Not medical advice. Consult a qualified healthcare professional before any protocol decision.
Synergies
- Gonadorelin MODERATE
Gonadorelin (pituitary LH pulse) and hCG (direct Leydig cell stimulation) both preserve testicular function but via different mechanisms. Some protocols use both for comprehensive HPG preservation. - Kisspeptin-10 MODERATE
Kisspeptin stimulates GnRH/LH release from the pituitary; hCG acts directly on the testes. Upstream + downstream HPG axis support.
Myths & misconceptions
Evidence gaps
- Optimal dose for testicular preservation during TRT not established in RCT (clinical protocols vary 250–500 IU based on practitioner experience).
- Long-term effects on Leydig cell sensitivity with chronic hCG use.
- Comparison data with gonadorelin for testicular preservation outcomes.
Safety notes
FDA-approved with extensive safety record. Common in TRT: oestradiol elevation (hCG stimulates aromatase in testes), testicular sensitivity/discomfort. Monitor testosterone, oestradiol, LH, FSH. High doses associated with oestrogen-related side effects. Medical supervision recommended.
Biomarkers to monitor
Primary-source citations
- PMID 18812492 — The effects of gonadotropin treatment on testicular function in hypogonadal men (J Clin Endocrinol Metab. 2008)
Frequently asked
What is hCG?
hCG (Human Chorionic Gonadotropin — LH Analogue) is a research compound classified in our library as Tier B — Some human data + strong preclinical evidence.. Endogenous LH analogue — FDA-approved for fertility. Used clinically to maintain testicular function and spermatogenesis during TRT.
What is the evidence tier for hCG?
We classify hCG as Tier B: Some human data + strong preclinical evidence. See our full peptide evidence tiers explainer for how we assign S/A/B/C/D.
What is the research dose of hCG?
For hCG, typical research dose is 250–500 IU (TRT adjunct) / 5,000–10,000 IU (fertility), route is SubQ / IM, half-life is ~24–36 hours. Protocols vary by research goal — see the protocols section on this page for standard and advanced dosing schedules. Research use only, not medical advice.
Is hCG safe?
FDA-approved with extensive safety record. Common in TRT: oestradiol elevation (hCG stimulates aromatase in testes), testicular sensitivity/discomfort. Research context only — no compound on this site is approved for human therapeutic use unless explicitly noted.