HCG: The Complete Guide

This guide covers what HCG is, what it is approved to treat, how it is used in male fertility and testosterone therapy, and why the evidence rejects it for weight loss. It is educational only and not a substitute for advice from a qualified healthcare professional. Sources are listed at the end.

HCG is unusual among the compounds covered in this Info Center. Most of them are research compounds with thin evidence and no approval anywhere. HCG is a properly approved prescription medicine with decades of clinical use, a well-understood mechanism, and a body of trial evidence behind its real indications.

It also carries one of the most persistent myths in the diet industry. Both things are true at once, and a useful guide has to handle them separately rather than letting one contaminate the other.

What HCG Is

Human chorionic gonadotropin is a hormone produced by the placenta in early pregnancy. It is what home pregnancy tests detect — the test strip is looking for HCG in urine.

Structurally it is a glycoprotein: a protein with sugar chains attached. It is built from two separate subunits that join together. The alpha subunit, 92 amino acids long, is shared with three other hormones — luteinising hormone, follicle-stimulating hormone and thyroid-stimulating hormone. The beta subunit, 145 amino acids, is unique to HCG and is what gives it its identity.

At roughly 36,700 daltons, HCG is considerably larger than the compounds usually described as peptides, which typically run to a few thousand daltons at most. Strictly it belongs with proteins. Our guide to the different types of peptides covers where those boundaries sit and why they are conventions rather than hard lines.

Where it comes from

Two manufacturing routes exist, and the distinction is worth knowing.

• Urinary-derived HCG is purified from the urine of pregnant women. This is the traditional source and covers most conventional products.
• Recombinant HCG is produced by engineered cells in culture, giving a more consistent and purer product. It is the same molecule.

This is a good illustration of a general point covered in our guide on natural versus synthetic peptides: the biologically derived version is not the safer one by default, and the manufactured version is not a lesser copy.

How It Works

HCG's beta subunit closely resembles that of luteinising hormone, and the two bind the same receptor — known as the LH/HCG receptor. Wherever LH would act, HCG acts, only for longer.

In men, that receptor sits on the Leydig cells of the testes, which produce testosterone. When LH arrives from the pituitary, those cells make testosterone. HCG delivers the same instruction from outside, which means it raises testosterone by stimulating the testes to produce it rather than by supplying testosterone directly.

In women, the receptor is on ovarian cells. A surge of LH is what triggers ovulation, so a dose of HCG can be used to trigger the final maturation and release of an egg at a chosen moment — which is exactly how it is used in fertility treatment, where it is often called a trigger shot.

What It's Approved For

HCG holds genuine regulatory approval — which puts it in a different class from most compounds discussed on this site. Approved indications generally cover three things:

Notice what is not on that list. There is no approved indication for weight loss, body composition, general "low testosterone" in men with an intact pituitary, or anti-aging. Products carry a required statement to that effect.

HCG, Testosterone and Fertility

This is the use most men reading this page are actually interested in, and it rests on a genuine and well-documented problem.

The problem testosterone therapy creates

When you take testosterone from outside, your brain detects plenty of it and stops sending the signals that tell the testes to work. LH and FSH fall. The testes, no longer receiving instructions, shrink and stop producing testosterone locally. Because sperm production depends on that very high internal concentration, sperm counts fall — sometimes to zero.

Men are often not warned about this clearly enough before starting. It is not a rare side effect; it is the expected consequence of the mechanism.

What HCG does about it

Because HCG mimics LH, it keeps instructing the Leydig cells directly, bypassing the suppressed pituitary signal. The testes keep working, internal testosterone concentration is maintained, and sperm production can continue.

The evidence here is reasonably good by the standards of this field. A 2005 study in the Journal of Clinical Endocrinology & Metabolism gave men weekly testosterone alongside either placebo or one of three low HCG doses and measured testosterone concentrations directly inside the testes. Testosterone alone caused a steep fall. Adding HCG preserved intratesticular testosterone in a dose-dependent way, with even the lowest dose largely preventing the collapse. Later clinical follow-up reported that men on testosterone with concurrent HCG maintained semen parameters rather than becoming azoospermic.

A second use follows from the same mechanism: some men with secondary hypogonadism — where the testes are capable but the signal is not arriving — use HCG on its own rather than testosterone, which raises testosterone while keeping the whole axis running and testicular size intact.

The Weight-Loss Claim

The HCG diet began with a British physician, Albert Simeons, who published his idea in The Lancet in 1954 and later a book promoting it. The claim was that HCG injections combined with a severely restricted diet would mobilise fat specifically from the hips, thighs and abdomen while suppressing hunger.

The claim has been tested repeatedly, and it does not survive.

A 1977 double-blind randomised trial published in the Western Journal of Medicine compared HCG injections against placebo injections in people following the same diet. Weight loss was identical between the two groups. There was no difference in hunger, no difference in mood, and no difference in where the weight came off. The authors' conclusion was blunt: placebo injections appear to be as effective as HCG.

A 1995 meta-analysis in the British Journal of Clinical Pharmacology pooled the controlled trials and reached the same verdict in unusually direct language: there is no evidence that HCG is effective in the treatment of obesity, it does not bring about weight loss or fat redistribution, and it does not reduce hunger. No subsequent quality trial has contradicted it. The American Society of Bariatric Physicians has stated that HCG cannot be recommended for weight loss.

Regulators followed. In December 2011 the FDA and FTC jointly declared over-the-counter HCG weight-loss products fraudulent and illegal and sent warning letters to manufacturers. The agencies noted that the recommended diet accompanying these products was low enough to carry risks of malnutrition, electrolyte imbalance, cardiac arrhythmias and gallstone formation. Homeopathic labelling made no difference to the legal position.

If weight loss is the actual goal, the compounds with real trial evidence are a different class entirely — see how GLP-1 peptides work for weight loss.

Dosing in the Research

HCG is dosed in International Units, which measure biological activity rather than weight. This trips people up constantly, because IU are not the same as the units marked on an insulin syringe — those measure volume. Our IU dosage calculator handles the conversion, and the distinction is explained there in full.

The figures below describe what appears in published clinical literature. They are context, not instruction — the appropriate dose for any individual depends on diagnosis, goal, concurrent medication and monitoring.

Two practical notes. HCG's long half-life means effects from one injection persist over a day or more, which is why schedules are usually every-other-day or twice weekly rather than daily. And because it is supplied as a powder in IU rather than milligrams, reconstitution arithmetic differs slightly from the rest of the catalogue — the calculator linked above is built for it.

Side Effects & Safety

HCG has a long clinical track record, and used appropriately its side effect profile is reasonably well characterised. Most issues in men are downstream of raising testosterone rather than effects of HCG itself.

In men

• Raised oestrogen and gynecomastia. The most-reported issue. Testosterone converts to oestradiol, and HCG also stimulates that conversion within the testes, so oestradiol can rise disproportionately. Breast tenderness or enlargement is the visible result.
• Acne, oily skin and fluid retention, as with any rise in androgens.
• Raised haematocrit — thicker blood — which is monitored on bloodwork rather than felt.
• Mood changes, reported during therapy and generally attributed to shifting testosterone and oestradiol.
• Prostate considerations in older men, as with any androgen therapy.

In women

• Ovarian hyperstimulation syndrome. The serious one. The ovaries over-respond, become enlarged and leak fluid into the abdomen. Mild cases are uncomfortable; severe cases are a medical emergency. This is a principal reason fertility treatment is closely supervised.
• Multiple pregnancy, when used to induce ovulation.

Both

Injection-site reactions are common and mild. As with any injected protein, allergic reactions are possible and rare — swelling of the face or throat, difficulty breathing or spreading hives require immediate medical attention rather than management. Our page on minimizing side effects covers injection technique.

Regulatory & Anti-Doping

HCG is an approved prescription medicine in the United States, the European Union and most other jurisdictions, for the indications listed earlier. That is a meaningful difference from the research compounds covered elsewhere on this site, and our guide on research versus pharmaceutical peptides explains why manufacturing standards differ so sharply between the two supply routes.

What it is not approved for is weight loss, and products carry a required statement saying so.

The anti-doping position is unusual

HCG appears on the World Anti-Doping Agency Prohibited List under S2, in the subcategory covering testosterone-stimulating peptides in males. The prohibition applies to men only, and it applies at all times — in and out of competition.

The asymmetry has a straightforward explanation. In men, HCG raises testosterone and is therefore performance-relevant; it can also mask exogenous testosterone use by keeping testicular function apparently intact during a steroid cycle. In women, HCG rises naturally in pregnancy and does not produce the same effect, so testing for it would be neither meaningful nor fair.

Detection is well established. Anti-doping guidance treats urinary HCG above a defined threshold as an indicator of administration in male athletes, using the same immunoassay technology as a pregnancy test. Any man in a tested sport should treat HCG as prohibited and confirm the current position with his national anti-doping organisation.

Common Questions

Important disclaimer: The information in this guide is general educational content only. It is not medical advice, a prescription, or a personalized recommendation. Human chorionic gonadotropin is an approved prescription medicine in the United States, the European Union and other jurisdictions for ovulation induction in women, hypogonadotropic hypogonadism in males, and prepubertal cryptorchidism; it should be obtained and used under the supervision of a qualified prescriber. It is not approved anywhere for weight loss, and products carry a required statement that there is no substantial evidence it increases weight loss beyond that resulting from caloric restriction, causes a more favourable distribution of fat, or decreases hunger associated with calorie-restricted diets. In December 2011 the US Food and Drug Administration and Federal Trade Commission declared over-the-counter HCG weight-loss products fraudulent and illegal; the agencies noted that the severely restricted diets accompanying such products carry risks including malnutrition, electrolyte imbalance, cardiac arrhythmias and gallstone formation. Nothing on this page should be read as describing or endorsing such a diet. Dosing figures discussed reflect what is reported in published clinical literature; they are not endorsements of those doses for any specific individual, and appropriate dosing depends on diagnosis, monitoring and concurrent treatment. Use of HCG alongside testosterone therapy or fertility medication interacts directly with that treatment and requires prescriber involvement. Documented adverse effects include elevated oestradiol and gynecomastia, acne, fluid retention, raised haematocrit and mood changes in men; ovarian hyperstimulation syndrome and multiple pregnancy in women; and injection-site reactions and rare hypersensitivity reactions in both. Hormone-sensitive cancers are generally a contraindication. HCG is prohibited at all times in male athletes under the World Anti-Doping Agency Prohibited List section S2, and detection methods are established; the prohibition does not apply to female athletes. If restriction of food intake has become difficult to control, support from a qualified healthcare professional is more useful than any hormone. Always consult a qualified healthcare professional before beginning any protocol. Products sold by Peptides Costa Rica are intended for laboratory and research purposes only.