HCG Overview, Dosing & Safety | Peptide Database

HCG (Human Chorionic Gonadotropin)

Human Chorionic Gonadotropin | LH Receptor Agonist

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HCG is a glycoprotein hormone naturally produced by the placenta during pregnancy that binds LH receptors to stimulate testosterone and estrogen biosynthesis. FDA-approved for cryptorchidism, hypogonadotropic hypogonadism, and ovulation induction.

Binds to LH receptors on Leydig cells in testes, stimulating testosterone production with a half-life of 24-36 hours, peak levels 6-12 hours post-injection, and 40-50% bioavailability via SubQ or IM routes.

Molecular Data

Research Indications

Maintains intratesticular testosterone at baseline during testosterone therapy, preventing atrophy and preserving fertility.

FDA-approved for secondary hypogonadism; combined with FSH for spermatogenesis induction.

Restores testicular function after anabolic steroid cycles.

FDA-approved trigger for follicular maturation; 15-25% pregnancy rate per cycle.

FDA-approved for prepubertal undescended testes not due to anatomical obstruction; ~25% success rate.

Dosing Protocols

Subcutaneous or intramuscular injection. Administer 2-3 times weekly, evenly spaced. For TRT, many inject HCG on days between testosterone injections.

TRT Adjunct (Low)

250-500 IU

Every other day

SubQ/IM

TRT Adjunct (Standard)

500-1000 IU

Twice weekly

HCG Monotherapy

1500-2000 IU

2-3x weekly

IM

Fertility (with FSH)

Cryptorchidism (Pediatric)

1000-5000 IU

2-3x weekly for 3-4 weeks

Ovulation Trigger (Female)

5000-10,000 IU

Single dose

IM/SubQ

PCT Protocol

1000-1500 IU

Every other day for 2-3 weeks

Reconstitution Instructions

HCG lyophilized powder vial (typically 5000 or 10,000 IU)

Bacteriostatic water or sodium chloride diluent (provided)

Insulin syringes (29-31 gauge for SubQ)

Alcohol prep pads

1 Remove vial and diluent from packaging

2 Clean rubber stoppers with alcohol swabs

3 Draw diluent into syringe (typically 1-2mL provided)

4 Slowly inject diluent into HCG vial, aiming at vial wall

5 Gently swirl to dissolve - do not shake vigorously

6 Allow to sit until completely dissolved and clear

7 Calculate concentration (e.g., 5000 IU in 2mL = 2500 IU/mL)

8 Label with reconstitution date and concentration

9 Store reconstituted HCG at 2-8°C

10 Use within 30-60 days

Interactions

What to Expect

Side Effects & Safety

Common Side Effects

Gynecomastia (breast tenderness/swelling) due to increased estrogen

Headaches, irritability, and mood swings (especially initially)

Fluid retention and edema

Potential antibody formation with long-term use

Stop Signs - Discontinue if:

Signs of gynecomastia (breast tenderness, swelling, nipple sensitivity)

Severe or persistent headaches

Signs of blood clots (leg swelling/pain, shortness of breath, chest pain)

Allergic reactions (rash, hives, difficulty breathing, facial swelling)

Severe abdominal pain or bloating in women (possible OHSS)

Testicular pain or swelling beyond normal

Significant mood changes (depression, aggression, severe irritability)

Vision changes

Contraindications

Hormone-sensitive cancers (prostate, breast)

Pregnancy (except as prescribed)

Precocious puberty risk in children

Quality Checklist

Good Signs

White to off-white lyophilized powder or cake in sealed vial

Completely clear solution after reconstitution

Proper labeling: Pregnyl, Novarel (urinary), Ovidrel (recombinant)

Clear expiration and lot number

Cold chain compliance (recombinant requires refrigeration throughout)

Warning Signs

Generic/compounding pharmacy products - quality varies

Ensure compounding pharmacy is accredited

Bad Signs

Cloudiness, discoloration, or floating particles indicates degradation

Compromised vial seal or expired product

Frequently Asked Questions

How much HCG is needed to maintain fertility during testosterone replacement therapy?

A landmark clinical study found 250 IU of HCG every other day maintained intratesticular testosterone within 7% of baseline during testosterone therapy, preserving fertility. This low dose is far less than other protocols suggesting HCG is remarkably potent—even minimal doses maintain testicular function when properly timed.

Why does HCG cause gynecomastia if it just stimulates testosterone?

HCG stimulates testosterone production, but testes also express aromatase enzyme that converts testosterone to estrogen. The increased testosterone availability combined with enhanced intratesticular aromatase activity results in elevated estrogen, causing breast tenderness and gynecomastia. Aromatase inhibitors help prevent this side effect.

Can antibodies to HCG develop with long-term use and reduce effectiveness?

Potential antibody formation to HCG with extended use is a theoretical concern, though clinical significance remains unclear. Some users report diminishing HCG effectiveness after months of continuous use. Cycling HCG with breaks or rotation to GnRH analogs may prevent tolerance development.

What's the success rate of HCG for treating cryptorchidism (undescended testes)?

Meta-analysis of HCG in cryptorchidism shows approximately 24% success rate—modest but clinically relevant for select cases. Success is higher for bilateral versus unilateral cryptorchidism. This low success rate led to surgery becoming the standard treatment for most cases, though HCG remains an initial option.

References

29 men randomized to testosterone enanthate plus 125, 250, or 500 IU HCG every other day. 250 IU maintained intratesticular testosterone within 7% of baseline, preserving fertility potential during TRT.

HCG monotherapy safe and efficacious for hypogonadal symptoms. Erectile dysfunction improved in 86% (19/22), libido in 80% (20/25). No thromboembolic events.

Combined HCG and FSH therapy induces spermatogenesis in 86% (95% CI 82-91%) of men with hypogonadotropic hypogonadism. HCG alone achieves 40% (95% CI 25-56%).

Meta-analysis of 13 studies with 872 boys and 1,174 undescended testes. Overall HCG success rate of 24%. Significant effect on bilateral but not unilateral cryptorchidism.

Confirmed ~25% success rate for HCG in cryptorchidism treatment. All side effects were transitory and not severe.

Related Peptides

Commonly combined in TRT to maintain testicular function and preserve fertility.

Complementary mechanisms for HPG axis stimulation.

Protective combination for metabolic health.

Disclaimer

This information is for educational and research purposes only. Consult a healthcare professional before use.