HCG: Reference Overview and Reconstitution Notes

HCG

What it is

HCG (human chorionic gonadotropin) is a dimeric glycoprotein hormone in the gonadotropin family, naturally produced by the placenta and built from an alpha subunit and a beta subunit. Its alpha subunit is closely related to those of the pituitary gonadotropins LH and FSH, while its beta subunit gives HCG its distinct identity and signaling profile.

Research context and categorization

HCG is grouped under the reproductive and endocrine (hormone) category. Because its activity closely resembles luteinizing hormone (LH), it is commonly discussed in relation to gonadal signaling in both sexes.

In females, it is studied in the context of triggering final follicular maturation and ovulation, including within assisted reproductive workflows. In males, it is investigated for its role in stimulating testicular steroidogenesis, and it is commonly discussed in relation to endogenous testosterone signaling and spermatogenesis support. It is also referenced in the context of prepubertal undescended testicles (cryptorchidism) not caused by an anatomical obstruction.

Separately, HCG has been marketed for weight regulation, but the FDA has stated there is no substantial evidence that HCG is effective for weight loss and has advised against over-the-counter HCG products sold for that purpose. That particular use is not confirmed or approved.

Status

  • Regulatory status: FDA-approved for specific indications, including induction of ovulation and final follicular maturation in selected infertile patients, treatment of prepubertal cryptorchidism not due to anatomical obstruction, and selected cases of hypogonadotropic hypogonadism in males. It is a prescription product in these approved uses, not a research-only compound.
  • Sport status: Prohibited under the WADA Prohibited List. Chorionic gonadotropin (CG) and luteinizing hormone (LH) and their releasing factors are listed in class S2 (peptide hormones, growth factors, related substances and mimetics) and are prohibited in males at all times, both in and out of competition.

Reconstitution notes (general)

HCG is typically supplied as a lyophilized (freeze-dried) powder that is reconstituted with bacteriostatic water before use. Concentration equals the total units in the vial divided by the millilitres of bacteriostatic water added. For example, a 5,000 IU vial reconstituted with 2 mL yields 2,500 IU per mL, and a 10,000 IU vial reconstituted with 10 mL yields 1,000 IU per mL. Use the calculator at /pages/tools to work out concentration from vial units and water volume.

Dilution and handling notes (compound-specific)

HCG is measured in international units (IU) rather than milligrams, so vials are commonly labeled 5,000 IU or 10,000 IU, and the chosen water volume sets the working concentration. A widely referenced approach is roughly 1 mL of bacteriostatic water per 1,000 IU, which places typical reconstitution volumes anywhere from about 2 mL to 10 mL per vial depending on the concentration wanted. Bacteriostatic water (water containing about 0.9 percent benzyl alcohol as a preservative) is generally preferred over plain sterile water because the reconstituted vial is stored and drawn from repeatedly rather than used all at once.

The powder generally dissolves readily and does not need aggressive mixing. The practical technique is to direct the diluent slowly against the inner glass wall rather than onto the powder, then swirl gently until the solution turns clear. The important quirk is that HCG is a fragile glycoprotein and should not be shaken. Vigorous shaking can foam the solution and stress the protein structure, which may reduce potency, so gentle swirling is the standard fix. A properly mixed vial should be clear and colorless. Cloudiness, discoloration, gelling, or visible particles indicate a problem with the mix or the material, and such a vial is discarded rather than salvaged.

Handling and storage

Store reconstituted HCG refrigerated at 2 to 8 degrees Celsius and keep it out of direct light. Wipe the rubber stopper with alcohol before each puncture, and label the vial with the reconstitution date so its age is always clear. Observe the general reference window of roughly four weeks refrigerated for a mixed vial, with potency declining over time. Discard anything that has gone cloudy, changed color, or shows floaters. Unmixed lyophilized powder is generally kept at controlled room temperature until reconstitution, per the specific product's labeling.

Related reading

Tools and supplies

For laboratory and research reference only. Educational content, not medical, dosing, injection, or therapeutic guidance, and not intended for human or animal use. Any research uses described are investigational and not confirmed or approved benefits. Confirm anything involving health with a licensed professional. References linked above.