HCG // LH Analog
The traditional gold standard for maintaining testicular function during TRT. HCG mimics luteinizing hormone (LH) activity at Leydig cells, directly stimulating intratesticular testosterone production and preserving spermatogenesis. FDA-approved, widely prescribed, and the most established gonadal support compound in hormone optimization.
Direct testicular stimulation.
HCG binds the same receptor as LH on Leydig cells in the testicles. This directly stimulates intratesticular testosterone (ITT) production — the local testosterone concentration needed for spermatogenesis. Without ITT, sperm production ceases regardless of serum testosterone levels.
250–500 IU, two to three times weekly.
HCG is dosed 2–3 times per week as a TRT adjunct. Lower doses (250 IU) are used for maintenance; higher doses (500 IU) for more aggressive testicular stimulation or fertility protocols. Doses above 1000 IU per injection are generally unnecessary and increase side effects.
Decades of clinical use — the established standard.
HCG has been used in reproductive medicine since the 1960s. Its role in maintaining testicular function during exogenous testosterone use is supported by decades of clinical experience and published data.
Key studies demonstrated that HCG supplementation during TRT maintains intratesticular testosterone at levels sufficient for spermatogenesis, preserves testicular volume, and improves sperm parameters compared to unsupported TRT.
Recent availability changes (FDA regulation of compounding pharmacies) have shifted some TRT protocols from HCG to Gonadorelin. Both remain valid options — HCG acts directly on the testicle (downstream), while Gonadorelin acts on the pituitary (midstream). Many protocols use both.
Gonadal support comparison.
| Compound | Level | Half-Life | Fertility | Availability |
|---|---|---|---|---|
| HCG | Gonadal (direct) | 24–36 hours | Strong preservation | Rx / Compounding |
| Gonadorelin | Pituitary | ~4 minutes | Good preservation | Compounding |
| Kisspeptin-10 | Hypothalamus | ~4 minutes | Theoretical | Research only |
| Clomiphene | Pituitary (SERM) | ~5 days | Good | Rx (off-label) |
What to watch for.
HCG's side effect profile is manageable with proper protocol adherence. Baseline blood work before starting and periodic monitoring during use is essential.
- Estradiol increase (aromatization from ITT — may need AI)
- Water retention
- Gynecomastia risk (estrogen-related — monitor)
- Headache
- Injection site reactions
- Mood changes (hormonal fluctuation)
- Doses above 1000 IU increase side effects without proportional benefit
- Desensitization risk at very high doses (rare at standard doses)
- Total and free testosterone
- Estradiol (critical — HCG increases E2 via aromatization)
- LH and FSH (suppressed on TRT, not reliable markers)
- SHBG
- Hematocrit/hemoglobin
- PSA
- Semen analysis (if fertility is the goal)
- Comprehensive metabolic panel
- Gonadorelin for combined pituitary + gonadal support
- Aromatase inhibitor may be needed (HCG increases estradiol)
- Standard component of modern TRT protocols
- Kisspeptin-10 for three-level HPG axis coverage
- PT-141 for desire enhancement alongside hormonal optimization
- Track estradiol closely — HCG's main management issue
- Lyophilized: refrigerate at 2–8°C
- Reconstituted: refrigerate, use within 30 days
- Protect from light
- Do not freeze
- Available via prescription (Pregnyl, generic) or compounding pharmacy
Compounds that complement HCG.
The gold standard for testicular preservation — for good reason.
HCG has the longest track record of any gonadal support compound. Decades of clinical use, FDA approval, and clear mechanistic rationale. If you're on TRT, HCG (or Gonadorelin, or both) is not optional — it's the difference between maintaining your fertility and reproductive function or losing it. The main management issue is estradiol: HCG stimulates intratesticular testosterone production, some of which aromatizes to estrogen. Track E2 closely and use an AI if needed. 250–500 IU 2–3x per week is the sweet spot — more is not better. Work with a physician who runs comprehensive hormonal panels.
Our free Protocol Guide includes the complete TRT support section — HCG, Gonadorelin, estradiol management, and comprehensive blood work tracking.