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HCG (Human Chorionic Gonadotropin)

Gonadotropinim · inferred

LH analogue that directly stimulates testicular Leydig cells to produce testosterone and maintain testicular volume. Half-life ~33 hours after IM/SC injection. Typically dosed at 250-500 IU 2-3x/week alongside TRT to preserve fertility and prevent testicular atrophy.

Projected serum levels — 500 IU (≈ 0.045 mg), twice weekly

HCG (Human Chorionic Gonadotropin)
HCG (Human Chorionic Gonadotropin) modeled serum levels, 500 IU (≈ 0.045 mg) twice weekly over 18 days Population-based pharmacokinetic estimate. Steady state reached after approximately 7 days. 0 0.25 0.50 0.75 1 Day 0 Day 4 Day 9 Day 13 Day 18 Time on a regular schedule ≈ steady state · day 7
HCG (Human Chorionic Gonadotropin) modeled serum levels with a loading dose of 620 IU, then 500 IU (≈ 0.045 mg) twice weekly The first dose is larger so levels approach steady state faster. 0 0.25 0.50 0.75 1 Day 0 Day 4 Day 9 Day 13 Day 18 Time on a regular schedule

Maintenance schedule: 500 IU (≈ 0.045 mg) twice weekly (im).

Loading schedule: 620 IU on day 1, then 500 IU (≈ 0.045 mg) twice weekly — reaching therapeutic levels sooner.

Modeled steady state after ~7 days: peak ≈ 0.024 mg, trough ≈ 0.007 mg body load. Population-based estimate over 18 days for a reference dose at a 70 kg reference body mass — the interactive app scales curves to your doses, timing, and body mass.

Key facts

Category
Gonadotropin
Route modeled
IM
Model confidence
inferred
Half-life
36 h
Common dose
500 IU (≈ 0.045 mg)
Suggested maximum
2k IU/day
Reference dose range
250–2k IU (single dose)
Suggested cadence
twice weekly

Research behind this entry

  1. Disappearance of Exogenously Administered Human Chorionic Gonadotropin Damewood MD et al. · Fertility and Sterility, 1989 DOI

    Measured hCG disappearance (PMID:2776893) after IM injection in 34 IVF patients, finding exponential elimination with mean half-life of 2.32 days and levels detectable up to 14 days post-injection.

  2. Pharmacodynamics and Pharmacokinetics after Subcutaneous and Intramuscular Injection of Human Chorionic Gonadotropin Saal W et al. · Fertility and Sterility, 1991 DOI

    Compared SC vs IM hCG injection (PMID:1712735), showing delayed peak and prolonged half-life with SC route, with peak serum levels at 6-12 h (IM) vs 16-20 h (SC).

2 published studies referenced in the app, each with a plain-language summary.