✓ Medically reviewed by · Last reviewed: May 2026
Pharmacy Researcher · 8 years experience
Pharmacy researcher with 8 years reviewing clinical drug information, generic formulation equivalence, and international pharmaceutical standards. Focuses on patient-facing accuracy in medication education.
Key Takeaways — HCG Dose Protocol Guide
- HCG dosing is indication-driven. A fertility-trigger dose (5,000–10,000 IU once) is 20–40× larger than a TRT-adjunct dose (250 IU 3× weekly). Wrong dose for the indication produces wrong outcomes.
- TRT-adjunct dosing typically runs 250–500 IU subcutaneously 2–3× weekly to preserve testicular volume and intratesticular testosterone during exogenous testosterone therapy.
- PCT dosing typically runs 500–1,500 IU EOD (every other day) for 7–14 days at the start of recovery, followed by SERM phase. Higher doses or longer durations risk Leydig-cell desensitisation. See full PCT detail at our HCG PCT protocol guide.
- Reconstitution math matters. A 5,000 IU vial reconstituted with 2 mL bacteriostatic water yields 2,500 IU/mL; 1 mL yields 5,000 IU/mL. The same vial therefore delivers very different doses depending on diluent volume and syringe markings.
- Subcutaneous injection at TRT-adjunct doses is standard; intramuscular injection is preferred for fertility-trigger doses by some clinicians. Both routes are pharmacokinetically equivalent at the doses used.
- For the buying-guide context see our HCG buying guide 2026; for the injection vs drops question see HCG injections vs drops.
Indication-by-Indication Dose Reference
| Indication | Typical Dose | Frequency | Duration |
|---|---|---|---|
| Ovulation trigger (after FSH or clomiphene) | 5,000–10,000 IU (or recombinant 250 mcg) | Single dose | Once per cycle, ~36 hr before retrieval |
| Hypogonadotropic hypogonadism (men) | 500–4,000 IU | 2–3× weekly | Indefinite |
| TRT adjunct (testicular preservation) | 250–500 IU | 2–3× weekly | Co-administered with TRT |
| Spermatogenesis induction (with FSH) | 1,500–2,500 IU | 2× weekly | 3–24 months |
| Cryptorchidism (boys) | 500–1,500 IU | 2× weekly | 4–6 weeks |
| PCT (post-cycle) | 500–1,500 IU | EOD | 7–14 days, then SERM phase |
The dose ranges above reflect mainstream prescribing practice in fertility, endocrinology, and TRT-clinic medicine. They are not personalised recommendations. Individual dose selection depends on body weight, baseline hormone levels, response to prior cycles (for fertility), and concurrent medications.
Reconstitution: How to Get From Vial to Syringe
HCG ships as lyophilised powder. The diluent is added at point of use. The choice of diluent volume determines the working concentration of the reconstituted solution — and therefore the volume of each subcutaneous injection. The math is straightforward:
- 5,000 IU vial + 1 mL bacteriostatic water = 5,000 IU/mL. Each 0.05 mL = 250 IU. Insulin-syringe markings: 5 units (on a U-100 syringe) = 250 IU.
- 5,000 IU vial + 2 mL bacteriostatic water = 2,500 IU/mL. Each 0.10 mL = 250 IU. Insulin-syringe markings: 10 units = 250 IU.
- 10,000 IU vial + 5 mL bacteriostatic water = 2,000 IU/mL. Each 0.125 mL = 250 IU. Insulin-syringe markings: 12.5 units = 250 IU.
- 10,000 IU vial + 10 mL bacteriostatic water = 1,000 IU/mL. Each 0.25 mL = 250 IU. Insulin-syringe markings: 25 units = 250 IU.
Practical note on syringe marking confusion
A 1 mL U-100 insulin syringe is marked in units of insulin, not in mL. The “units” on these syringes are insulin units, where 100 units = 1 mL. The IU markings on HCG and the units on insulin syringes are unrelated unit systems — but the syringe scale provides a convenient volumetric reference. Always reconstitute first, then reason in mL or syringe-units, not in HCG IU.
The most common dosing error in TRT-adjunct HCG is misreading the syringe scale. A patient prescribed 250 IU at 5,000 IU/mL who reads “5 units” on a U-100 syringe is correct. A patient who reads “25 units” — confusing the syringe-unit scale with the IU scale — has just injected 1,250 IU, which is five times the intended dose. The error is rarely catastrophic because HCG is well tolerated, but it accelerates Leydig-cell desensitisation and may produce supraphysiological estradiol via aromatisation.
Subcutaneous vs Intramuscular Injection
For doses up to 500 IU, subcutaneous injection in the abdomen or anterior thigh is standard. The needle is short (29–31 gauge, 8 mm) and the procedure is essentially identical to insulin self-administration. For fertility-trigger doses (5,000–10,000 IU), intramuscular injection in the gluteal or thigh muscle is preferred by some clinicians because the larger volume tolerates IM administration better. Pharmacokinetically, subcutaneous and intramuscular routes produce similar peak plasma levels and similar half-life (~36 hours for urinary HCG, slightly longer for recombinant).
Subcutaneous technique (TRT-adjunct dose)
- Wash hands; clean the injection site with an alcohol swab; allow to dry.
- Pinch a fold of skin in the abdomen (avoid 5 cm around the umbilicus) or anterior thigh.
- Insert the needle at 90° (or 45° if very lean) and inject the calculated volume.
- Withdraw, apply gentle pressure with the swab. No need to massage.
- Rotate sites to minimise lipohypertrophy.
Intramuscular technique (fertility-trigger dose)
- Use a 21–23 gauge needle, 1.5 inch length for gluteal injection.
- Locate the upper outer quadrant of the gluteus maximus.
- Aspirate to confirm no blood return before injecting.
- Inject slowly over 10–15 seconds.
- Withdraw, apply pressure, briefly massage to disperse.
Storage After Reconstitution
| Diluent | Refrigerated stability | Notes |
|---|---|---|
| Bacteriostatic water (0.9% benzyl alcohol) | 30 days | Standard for multi-dose vials; avoid in neonates |
| Sterile water for injection | 24 hours | No preservative; single-day use only |
| Manufacturer-supplied diluent (some brands) | Per label (typically 24 hr) | Read insert; some are sterile water, some buffered |
For TRT-adjunct dosing where a 5,000 IU vial is meant to last 5–6 weeks, bacteriostatic water is the only practical diluent. For fertility trigger or single-cycle PCT use, sterile water from the manufacturer-supplied ampoule is fine. Keep reconstituted HCG in the original vial in the refrigerator (2–8°C); freezing destroys peptide structure.
What HCG Does in Practice — Markers to Watch
For TRT-adjunct or fertility-induction users, three lab markers tell you whether HCG is working as expected:
- Total testosterone — Leydig-cell stimulation produces a testosterone bump. On TRT, this manifests as elevated trough testosterone with HCG vs without; on hypogonadotropic-hypogonadism monotherapy, total T should approach physiological range.
- Estradiol (E2, sensitive assay) — increased aromatase substrate may elevate E2; some users require concurrent anastrozole (Anastronat) or dose reduction.
- Testicular volume — measurable by orchidometer; TRT-adjunct HCG preserves volume that would otherwise atrophy by 30–50% within 6 months of testosterone-only therapy.
For PCT users the relevant markers are LH, FSH, and total testosterone over the recovery window — see our PCT protocol guide for the full timing and lab schedule.
Adverse Effects at Therapeutic Doses
- Injection-site reactions — usually mild; rotate sites.
- Acne, oily skin — secondary to elevated intratesticular testosterone; dose-responsive.
- Mild fluid retention — uncommon at TRT-adjunct doses; can occur at higher fertility-induction doses.
- Mood/libido changes — many TRT-adjunct users report improved libido and erectile function vs TRT alone, attributed to maintained intratesticular testosterone.
- Gynaecomastia — a risk if estradiol rises unchecked; manage with aromatase inhibitor or HCG dose reduction.
- OHSS — ovarian hyperstimulation syndrome is the dose-limiting risk in fertility induction; trigger doses individualised by follicle count.
Where to Buy HCG and Reconstitution Supplies
MedsBase ships WHO-GMP HCG and the reconstitution supplies you need:
- HUCOG 5000IU and HUCOG 10000IU — the two workhorse HCG SKUs.
- Eutrig HP 5000IU and ZyHCG HP 10000IU — alternative WHO-GMP brands.
- Bacteriostatic water — for 30-day multi-dose stability.
- Sterile water for injection — for single-day use.
All orders covered by the Reshipment Assurance Policy. Discreet shipping worldwide; statements show the processor, not MedsBase.
Frequently Asked Questions
What’s the standard TRT-adjunct HCG dose?
The most commonly prescribed protocol is 250 IU subcutaneous, three times weekly (e.g. Mon/Wed/Fri), for a total of 750 IU per week. Some clinicians use 500 IU twice weekly. The two regimens are pharmacokinetically similar; choice often comes down to patient preference for injection frequency. A 5,000 IU vial lasts about 6.5 weeks at 750 IU/week.
Can I split a fertility trigger dose into smaller injections?
No clinical reason to do so. The fertility trigger relies on a sustained LH-equivalent surge that follows a single 5,000–10,000 IU bolus. Splitting the dose blunts the surge and may prevent ovulation. Trigger timing is also critical (~36 hours before retrieval); splitting interferes with timing.
Why use bacteriostatic water instead of regular sterile water?
Bacteriostatic water contains 0.9% benzyl alcohol, which inhibits bacterial growth in the reconstituted vial and permits 30-day multi-dose use. Sterile water has no preservative — once the vial is punctured, it is single-use within 24 hours. For TRT-adjunct dosing where a vial lasts 5–8 weeks, bacteriostatic water is the only practical choice.
Insulin syringe vs tuberculin syringe — which should I use?
For TRT-adjunct doses (250–500 IU), a 1 mL U-100 insulin syringe with 29–31 gauge, 8 mm needle is standard. The fine markings (1-unit increments = 0.01 mL) provide adequate dose precision. Tuberculin syringes are appropriate for fertility-trigger doses (larger volume) or for IM injection.
Should I aspirate before injecting subcutaneously?
No. Aspiration is appropriate for IM injection in the gluteal region (where larger vessels run) but is not standard for subcutaneous injection. The subcutaneous tissue has minimal vascularity and the small needle bore makes meaningful aspiration impractical.
What if my HCG is cloudy after reconstitution?
Discard. Real reconstituted HCG is clear and colourless. Cloudiness indicates either bacterial contamination or product degradation. Do not inject; obtain a fresh vial.
Can HCG be frozen for longer storage?
The lyophilised powder, yes — most manufacturers allow refrigeration up to 24 months and frozen storage of the unreconstituted vial, although freezing is rarely necessary because powder stability is excellent. The reconstituted solution, no — freezing destroys the peptide structure. Once mixed, refrigerate at 2–8°C and use within 30 days (bacteriostatic water) or 24 hours (sterile water).
What if I miss a TRT-adjunct dose?
Take it as soon as practical, then return to the regular schedule. The 36-hour half-life means a missed dose causes only a transient dip in Leydig-cell stimulation. Do not double the next dose — there is no benefit and the higher peak may slightly elevate estradiol.
Medical Disclaimer: This article is educational and is not a substitute for personalised medical advice. HCG dosing must be matched to the indication and the patient. Anyone considering HCG for fertility, TRT-adjunct, PCT, or any other use should review their personal history and laboratory baseline with a qualified clinician. Information here reflects mainstream clinical practice as of 2026; specific manufacturer labelling may vary.
Written by
Sophie ChenPharmaceutical Content Researcher · 8 years experience
Sophie Chen is a pharmaceutical content researcher with 8 years covering generic medication access and clinical pharmacology. She specialises in international regulatory frameworks, bioequivalence standards, and patient-facing education on therapeutic drug classes. She is not a clinician.