hCG: what the studies show, status and safety

Summary

hCG is the hormone a pregnancy produces. As a medicine it comes in two forms: urinary hCG, purified from the urine of pregnant people, and recombinant hCG, made in cell cultures. Both are prescription-only in all seven markets on this page, and are used almost entirely in fertility medicine. The hCG diet is contradicted by the manufacturers' own package inserts.

Key findings at a glance

• hCG is two separately regulated substances, not one. Urinary hCG carries the substance code 20ED16GHEB and the classification code G03GA01. Recombinant choriogonadotropin alfa carries 6413W06WR3 and G03GA08 ^[1], ^[2].
• Prescription-only in all seven markets covered here. The oldest approval still on a register dates from 15 January 1968, in Switzerland ^[3].
• The two forms performed alike where it matters. A Cochrane review found no difference in ongoing pregnancy or live birth. The odds ratio was 1.15, with a range from 0.89 to 1.49, across 7 trials and 1,136 women ^[4].
• In undescended testicles, 19 percent success against 4 percent on a dummy treatment. That comes from randomised trials in 872 boys, pooled within a review of 33 publications ^[5].
• The package insert rejects the diet claim in capital letters. The American product information states that hCG has no known effect on fat mobilisation, appetite or hunger ^[6], ^[7].
• The 1995 meta-analysis found nothing either. Of 24 studies reviewed, 12 scored at least 50 out of 100 for method quality. Exactly one of those reported hCG to be useful ^[8].
• Overstimulation of the ovaries is the main danger. Among 186,168 stimulated cycles in Denmark, 2,261 women, or 1.2 percent, were admitted to hospital with that syndrome ^[9].
• Banned in sport, but only for men. The 2026 prohibited list names it under section S2.2.1, headed testosterone-stimulating peptides in males ^[10].

What it is

hCG stands for human chorionic gonadotropin. In pregnancy the placenta produces it, and it keeps the corpus luteum in the ovary working through the first weeks. As a medicine it exists in two forms that regulators keep firmly apart ^[1], ^[2].

Urinary hCG is collected and purified from the urine of pregnant people. It arrives as a freeze-dried powder that has to be dissolved, and it is injected into muscle. Recombinant hCG is made in cell cultures derived from hamster ovaries, arrives ready to use in a pre-filled syringe or pen, and is injected under the skin ^[6], ^[7], ^[11].

Brand names identify the products rather than describe them. Novarel from Ferring and Pregnyl from Organon are urinary hCG sold in the United States. They are licensed for undescended testicles, for low testosterone caused by a pituitary defect, and for triggering ovulation ^[6], ^[7].

Ovidrel from EMD Serono is the recombinant form in the United States, and Ovitrelle from Merck the same substance in Europe. Both are licensed only for fertility treatment in women ^[11], ^[12]. In Germany, Brevactid from Ferring is the urinary product ^[13].

Structurally hCG is a glycoprotein made of two chains that are not chemically bonded, only held together by charge. The alpha chain of 92 building blocks is shared with three other hormones. The beta chain of 145 building blocks is what makes it hCG ^[11], ^[14], ^[15].

That matters for measurement. In body fluids hCG circulates as a mixture of the intact hormone, loose chains and fragments, and only the intact pair is biologically active. Any test therefore has to measure the right thing ^[14].

Quick facts

How it works

hCG docks onto a single receptor, the one that luteinising hormone normally uses, and behaves like a long-acting copy of that hormone ^[7], ^[12].

• In women, it takes the place of the mid-cycle surge of luteinising hormone. That restarts the maturation of the egg, releases it, and turns the emptied follicle into a corpus luteum that makes progesterone and oestradiol ^[12].
• In men, it stimulates the Leydig cells in the testicles to produce androgens. That is why it raises the testosterone the body makes itself, rather than supplying it from outside ^[7].
• In pregnancy, hCG from the placenta keeps that corpus luteum going, which is the hormone's natural job ^[15].
• The alpha chain is identical in luteinising hormone, follicle-stimulating hormone and thyroid-stimulating hormone. Only the beta chain decides what the hormone does, and hCG also has a weak follicle-stimulating effect ^[15].

One line in the American product information is worth quoting because it settles an argument that keeps coming back. Under clinical pharmacology it states, in capital letters: "HCG HAS NO KNOWN EFFECT ON FAT MOBILIZATION, APPETITE OR SENSE OF HUNGER, OR BODY FAT DISTRIBUTION." ^[6], ^[7]

What the studies found

Triggering ovulation and IVF

Cochrane review The central question here is which trigger to use, not whether hCG works as one.

A review of 18 randomised trials compared the recombinant and the urinary form for the final ripening of egg cells. For ongoing pregnancy or live birth there was no difference. The odds ratio was 1.15, with a range from 0.89 to 1.49, in 7 trials with 1,136 women ^[4].

The same review found no difference in overstimulation of any severity, and none in miscarriage. Injection-site reactions were less frequent with the recombinant form in the fixed-effect model, at an odds ratio of 0.52 with a range from 0.35 to 0.76, but the difference disappeared in the random-effects model. Nine of the 18 trials were funded by manufacturers and the funding of five more was unclear ^[4].

Cochrane review A different comparison sets hCG against a GnRH agonist as the trigger.

In fresh cycles using a woman's own eggs, the agonist produced fewer ongoing pregnancies. The odds ratio was 0.70, with a range from 0.54 to 0.91, across 11 trials in 1,198 women. Early miscarriages were also more frequent, at an odds ratio of 1.74 with a range from 1.10 to 2.75 ^[18].

In egg donation cycles the picture flips. Live birth rates were the same, but severe overstimulation was far rarer with the agonist. The odds ratio was 0.05, with a range from 0.01 to 0.28, in 3 trials with 374 women ^[18].

What makes hCG effective as a trigger, its long action, is also what drives its main risk.

Cochrane review For simpler treatment, the picture is thinner. A 2025 review of insemination found no clear difference between an hCG trigger and waiting for the body's own surge. The odds ratio was 1.08, with a range from 0.50 to 2.37, in one trial with 392 couples. Recombinant and urinary hCG did not differ either, at an odds ratio of 1.13 with a range from 0.49 to 2.63, in one trial with 125 couples. The evidence was graded as low in trustworthiness ^[19].

Low testosterone and male fertility

Randomised mechanism study The best evidence in men is a study of 29 healthy volunteers over three weeks. They received testosterone, which shuts the testicles down, plus either a dummy treatment or hCG, and the testosterone inside the testicle was measured directly by needle sampling ^[20].

With the dummy treatment, the two pituitary signals fell to 5 percent and 3 percent of their starting values, and testosterone inside the testicle fell by 94 percent. With hCG it rose in step with the amount given. At the start, blood testosterone was only 1.2 percent of the level inside the testicle, so blood tests say little about what happens there ^[20].

This is the pharmacology behind using hCG after anabolic steroids. But the study measured a mechanism in 29 healthy men over three weeks. It tested neither the safety nor the benefit of that use.

Controlled study A later analysis of the same 29 men looked for a simpler marker. One blood value, 17-hydroxyprogesterone, tracked the level inside the testicle closely, which offers a less invasive way to follow it ^[21].

Observational In men whose low testosterone comes from a pituitary defect, hCG alone maintained sperm production in a case series, which is the setting the American licence describes ^[22].

Retrospective cohort A two-centre study followed 79 recreational bodybuilders after short-term anabolic steroid use. At the start, 89.9 percent had erectile dysfunction and 69.7 percent had no or very few sperm ^[23].

Both drug regimens sped up hormonal recovery. By month six, though, the values had normalised in every group, including the men given nothing at all. The study is retrospective and not randomised, and it shows a faster recovery rather than a better final outcome ^[23].

Undescended testicles

Meta-analysis In boys, hormonal treatment is an alternative to surgery, and the numbers are modest.

Pooling randomised trials in 872 boys with 1,174 undescended testicles gave a success rate of 19 percent for hCG, with a range from 13 to 25 percent. The hormone LHRH reached 21 percent, with a range from 18 to 24 percent, and a dummy treatment 4 percent, with a range from 2 to 6 percent. The review covered 33 publications and 3,282 boys in all ^[5].

Meta-analysis A later pooling of 13 randomised trials reported 24 percent for hCG and 19 percent for LHRH, with no significant difference between them. The effect showed only when both testicles were affected. Side effects were temporary, possible long-term harm remained unclear, and the authors explicitly declined to recommend hormonal treatment for every patient ^[24].

Meta-analysis A review of 27 studies put the absolute success rate at 22.4 percent. The risk ratio for full descent was 3.74, with a range from 2.78 to 5.04. Sperm production later in life improved measurably in the LHRH group but not in the hCG group ^[25].

The hCG diet

Meta-analysis This is the use most people have heard of, and it is the one with the clearest negative answer. A criteria-based meta-analysis published in 1995 reviewed 24 studies, eight of them controlled, and scored each one for method quality out of 100. The scores ranged from 16 to 73 ^[8].

Of the 12 studies scoring at least 50, exactly one reported hCG to be a useful addition. The authors concluded that there is no scientific evidence for any effect in obesity: no weight loss, no redistribution of fat, no reduction in hunger, no sense of well-being ^[8].

The approved American product information opens its indications section with the same finding, in capital letters: "HCG HAS NOT BEEN DEMONSTRATED TO BE EFFECTIVE ADJUNCTIVE THERAPY IN THE TREATMENT OF OBESITY. THERE IS NO SUBSTANTIAL EVIDENCE THAT IT INCREASES WEIGHT LOSS BEYOND THAT RESULTING FROM CALORIC RESTRICTION, THAT IT CAUSES A MORE ATTRACTIVE OR ‘NORMAL’ DISTRIBUTION OF FAT, OR THAT IT DECREASES THE HUNGER AND DISCOMFORT ASSOCIATED WITH CALORIE-RESTRICTED DIETS." ^[6], ^[7]

Randomised trials That conclusion rests on earlier randomised, double-blind work from the 1970s to the 1990s. Where the calorie restriction was the same in both groups, hCG and a dummy treatment produced the same result. Weight loss, hunger and sense of well-being did not differ ^[26], ^[27], ^[28], ^[29].

The regulator says the same. The FDA states that any loss comes from severe calorie restriction rather than from hCG. It also warns that 500 calories a day is not merely unhealthy but dangerous, naming gallstones, disturbed body salts and heart rhythm problems that can be fatal ^[30].

Only one interventional study on this question was ever registered. It enrolled 59 participants and asked whether hCG preserves lean mass during a very low calorie diet. It finished in December 2012 and has no results on file ^[31].

What is still unknown

• Whether hCG treatment of undescended testicles causes long-term harm. The trials measured descent, not what happens decades later ^[24].
• Whether any of the male uses outside the licensed indication are safe over time. The mechanism study ran for three weeks in 29 healthy men ^[20].
• Whether repeated exposure is safe in women. The European product information notes that repeated use has been studied only in men, and that trials in women covered a single treatment ^[12].
• Whether fertility treatment raises the risk of tumours of the reproductive organs. Cases have been reported, and the question is open ^[12].

Side effects and safety

The dominant risk is ovarian hyperstimulation syndrome, and it is a distinct illness rather than an exaggerated normal response ^[7], ^[12].

• Ovarian hyperstimulation syndrome. Blood vessels start leaking, and fluid collects in the abdomen, in the chest and rarely around the heart. Early signs are severe lower abdominal pain, nausea, vomiting and weight gain. A severe case can escalate within a day or a few days and become life-threatening ^[7], ^[12].
• How often. In the licensing studies of recombinant hCG, roughly 4 percent of women developed the syndrome and fewer than 0.5 percent a severe form. The risk rose with the amount given ^[12].
• How often in practice. In the Danish registry of 186,168 stimulated cycles between 2001 and 2017, 2,261 women were admitted to hospital with the syndrome, or 1.2 percent. The yearly figure moved between 0.9 and 1.4 percent with no trend. Three quarters stayed longer than a day, on average 4.3 days for early cases and 6.2 days for late ones ^[9].
• Timing. The peak comes about seven to ten days after treatment. If pregnancy occurs, the syndrome is more frequent, more severe and longer lasting, so monitoring runs for at least two weeks ^[7], ^[12].
• Blood clots. Rare, and usually alongside severe overstimulation, but the European text also lists them independently as a very rare effect. A recent clot or known risk factors raise the danger further ^[7], ^[12].
• Allergic reactions. Anaphylaxis has been reported with urinary products. Rash, hives, swelling and breathlessness are documented, and severe reactions including shock are classed as very rare in Europe ^[6], ^[7], ^[12].
• Multiple pregnancy. Triggering ovulation makes twins and higher multiples more common than natural conception, and higher multiples carry more risk for mother and babies ^[6], ^[12].
• Ovarian cysts. Existing cysts can enlarge, and a cyst can rupture and bleed into the abdomen ^[6].
• In men and boys. Breast tissue growth in men is documented, caused by the extra androgens being converted into oestrogens. In boys treated for undescended testicles, hCG can trigger puberty too early, and treatment is then stopped ^[6], ^[7].
• Fluid and salt retention. Seen occasionally after larger amounts, which is why heart disease, kidney disease, high blood pressure, epilepsy, migraine and asthma call for caution ^[6], ^[7].
• Common complaints. Headache, abdominal pain and bloating, nausea, vomiting and reactions where the needle went in are all classed as common in Europe. Diarrhoea and abdominal discomfort are less frequent ^[12].
• Injection-site reactions. Across 752 patients in four studies, these occurred in 14.6 percent on the recombinant form, 49 of 335, against 28 percent on the licensed urinary form, 92 of 328 ^[11].
• Benzyl alcohol. The solvent supplied with the American urinary products contains 0.9 percent benzyl alcohol, which has been linked to a fatal syndrome in premature babies. It is not for newborns ^[6], ^[7].

hCG must not be used where there is an allergy to it, or a tumour of the hypothalamus or pituitary. Cancer of the ovary, breast or womb rules it out, as does cancer of the breast or prostate in men ^[6], ^[7].

Unexplained vaginal bleeding and a malformation of the reproductive organs incompatible with pregnancy also rule it out. The European text adds active blood clotting disease and puberty that has started too early ^[12].

Two practical points round this off. Safe use requires regular monitoring of the response with blood oestradiol and ultrasound, and experience in treating fertility disorders. And for up to ten days afterwards, hCG can produce a false positive pregnancy test and can distort laboratory measurements of other gonadotropins ^[7], ^[12].

Why this page lists no doses

hCG is prescription-only in every market covered here, and its strength is expressed in two incompatible systems. Choosing an amount, or converting between international units and micrograms, belongs in the approved product information and in the prescription.

Development and approval status

The 2020 date is often reported as a ban on over-the-counter hCG. It was nothing of the kind. On 23 March 2020 the existing American applications converted by operation of law into biologics licences. That moved the products from one register to another and raised the manufacturing requirements ^[38].

Two rows need a word. Only the recombinant form holds a central European approval, and urinary hCG is licensed country by country. That is why the available products differ across Europe ^[12], ^[13], ^[34].

In the United Kingdom only the recombinant form could be confirmed on the public medicines compendium, so the urinary entry is left open rather than guessed ^[41].

The licensed uses differ too. The American licence for urinary hCG covers undescended testicles and low testosterone caused by a pituitary defect ^[6], ^[7]. The European licence for the recombinant form covers only adult women in fertility treatment, and states that there is no clinical experience in male conditions ^[12].

One American rule closes a side door. Products containing chorionic gonadotropins of animal origin are listed as withdrawn for reasons of safety or effectiveness, which means they may not be made up into compounded preparations ^[46]. The wider framework is set out under are peptides legal and FDA-approved peptides. Every entry describes the position on 7 September 2026.

Anti-doping

hCG is banned in sport for men. The 2026 prohibited list names it in section S2.2.1: "Testosterone-stimulating peptides in males including, but not limited to: chorionic gonadotrophin (CG), luteinizing hormone (LH), gonadotrophin-releasing hormone (GnRH, gonadorelin) and its agonist analogues" ^[10].

The heading above that section states that everything in the class is prohibited at all times, in and out of competition. None of it counts as a specified substance ^[10].

American college sport lists hCG by name in the same class ^[47]. The restriction to men follows physiology: in women the hormone occurs naturally, so it cannot serve as a marker.

Testing is done on urine, and only assays that recognise the intact pair of chains are accepted, because loose fragments would inflate the reading ^[48], ^[49]. In 570 urine samples from men, the average concentration of intact hCG was 0.04 international units per litre and the upper reference limit 0.21. A reporting threshold of 1.0 international units per litre of urine has been proposed, which the authors put at a false positive rate below 1 in 10,000 ^[48].

A study in ten healthy men found that the usual steroid ratios barely moved. The ratio of testosterone to luteinising hormone in blood rose sharply, which may make it the more sensitive marker ^[50]. The wider picture is at peptides banned in sport.

Compared with related peptides

Those neighbours are related by role rather than by chemistry. Menotropins are a urine-derived mixture rather than a single hormone, which is why they carry a separate classification code and sometimes contain hCG as a carrier of activity ^[3].

Gonadorelin and triptorelin act one step higher up, on the pituitary, and appear in the same anti-doping entry as hCG for exactly that reason ^[10].

The last row is the useful one. People reach for hCG because they want to lose weight, and that is the single thing it has never been licensed to do anywhere ^[30].

Common misconceptions

• "The hCG diet burns fat." The weight comes off because the regimen restricts calories severely. The 1995 meta-analysis found no benefit in the better studies, and the package insert says hCG has no known effect on fat mobilisation, appetite or hunger ^[6], ^[8].
• "500 calories a day is safe because hCG protects you." The regulator calls that intake not merely unhealthy but dangerous. It names gallstones, disturbed body salts and heart rhythm problems that can be fatal ^[30].
• "Homeopathic hCG drops are a legal over-the-counter product." Seven joint warning letters on 28 November 2011 classed them as unapproved and misbranded drugs. The letters also note that a product containing hCG cannot be a food supplement, because hCG was approved as a new drug in 1976 ^[35], ^[36].
• "The homeopathy exemption still covers them." The compliance guide firms relied on was withdrawn on 25 October 2019. The agency stated plainly that it never had the power to exempt a product class from approval. A final guidance followed in December 2022, and no homeopathic medicine has ever been approved ^[37], ^[39].
• "hCG, LH and hMG are interchangeable." hCG and luteinising hormone share a receptor but differ in their beta chain and last very different lengths of time. Menotropins are a different thing again, a urine-derived mixture with its own classification code ^[3], ^[7], ^[15].
• "Urinary and recombinant hCG are the same product." They have separate substance codes, separate classification codes, different routes and strengths expressed in different units. A Cochrane review found no clinical difference, and regulators still do not treat them as interchangeable ^[1], ^[2], ^[4].
• "hCG is a natural testosterone booster." It does raise the body's own testosterone. But the American licence covers only low testosterone caused by a pituitary defect, and the European licence for the recombinant form has no male indication at all ^[6], ^[12].
• "A positive pregnancy test after hCG proves a pregnancy." For up to ten days the treatment itself can produce a false positive result. The European text requires patients to be told so ^[12].
• "Test-kit hCG and medicinal hCG are different substances." Same hormone, different role. The Australian poisons standard captures it exactly: hCG sits in Schedule 4 except in pregnancy test kits. In cancer care the same hormone serves as a blood marker for germ cell tumours of the testicle ^[42], ^[51].
• "Grey-market hCG is equivalent." Unlicensed preparations have no verified content, purity or stability, and since only the intact pair of chains is active, a stated quantity says little. American rules also forbid compounding it, and European products are biologics with batch tracing duties ^[12], ^[46], ^[49].

Frequently asked questions

Is hCG a prescription-only medicine?

Yes, in every market examined here. It is prescription-only in the United States, the European Union, Germany, the United Kingdom, Australia, Canada and Switzerland. In the United States all hCG products became biologics on 23 March 2020, which tightened the rules on manufacturing and batch control. Australia lists it in Schedule 4 of its poisons standard, with an exemption only for pregnancy test kits.

What is hCG actually approved for?

Fertility medicine, in the main. The approved uses are triggering ovulation and the final ripening of egg cells, treating undescended testicles in boys, and treating a form of low testosterone caused by a pituitary defect. The European licence for recombinant hCG is narrower still and covers only adult women in fertility treatment. No market has ever licensed hCG for weight loss.

Does the hCG diet work for weight loss?

No. A meta-analysis published in 1995 reviewed 24 studies and found no scientific evidence that hCG helps in obesity. Of the 12 studies that scored at least 50 out of 100 for method quality, exactly one reported any benefit. The American package inserts say the same thing in capital letters, and add that hCG has no known effect on fat mobilisation, appetite or hunger.

Is homeopathic hCG a legal over-the-counter product?

No. The FDA and the FTC sent seven joint warning letters on 28 November 2011. They went to firms selling such drops, sprays and pellets for weight loss, and classed them as unapproved and misbranded drugs. The compliance guide that firms invoked was formally withdrawn on 25 October 2019, and a final guidance followed in December 2022. There is no separate 2020 ban on over-the-counter hCG.

What is the difference between urinary and recombinant hCG?

Where it comes from and how it is given. Urinary hCG is purified from the urine of pregnant people, comes as a powder and is injected into muscle. Recombinant hCG is made in hamster ovary cell cultures, comes ready to use and is injected under the skin. They carry different substance codes and different ATC codes, so regulators do not treat them as interchangeable, even though a Cochrane review found no difference in live births.

Is hCG a testosterone booster?

It does raise the body's own testosterone by stimulating the Leydig cells in the testicles, but it is not licensed for that purpose in healthy men. The American licence covers only low testosterone caused by a pituitary defect. The European licence for recombinant hCG has no male indication at all, and its product information states that there is no clinical experience in male conditions. Documented effects in men include breast tissue growth.

What is the most serious risk of hCG treatment?

Ovarian hyperstimulation syndrome. Blood vessels start leaking fluid into the abdomen and chest, and a severe case can become life-threatening within days. In 186,168 stimulated cycles in Denmark, 1.2 percent led to a hospital admission. Roughly 4 percent of women given recombinant hCG in the licensing studies developed the syndrome, and fewer than 0.5 percent a severe form.

Can hCG cause a false positive pregnancy test?

Yes. For up to ten days after it is given, hCG can interfere with the immunological measurement of hCG in blood or urine and produce a false positive result. The European product information requires that patients be told this. hCG also cross-reacts in laboratory tests for other gonadotropins, particularly luteinising hormone, so the laboratory needs to know about an ongoing treatment.

Is hCG banned in sport?

For men, yes, at all times. The 2026 prohibited list of the World Anti-Doping Agency names chorionic gonadotrophin under section S2.2.1, headed testosterone-stimulating peptides in males. Everything in that class is banned in and out of competition and none of it counts as a specified substance. The restriction to men follows physiology: in women hCG occurs naturally and is useless as a marker.

Why does this page list no hCG doses?

Because hCG is prescription-only in every market covered here. Its strength is also expressed in two incompatible systems, international units for the urinary form and micrograms of protein for the recombinant one. Choosing an amount, and converting between those systems, belongs in the approved product information and in the prescription. The studies here are reported by design and result only.

Cite this page

The facts on this page were checked on 7 September 2026, and the register searches behind the status table were run on that date. Licensed medicines gain new warnings over time, so the version and the date matter as much as the text. On that day the ClinicalTrials.gov registry listed 409 registered studies of this substance ^[31].

myPeptides Research & Editing. (2026). hCG: what the studies show, status and safety. Version 1.0, 7 September 2026. myPeptides Peptide Register. Retrieved from https://mypep.app/peptides/hcg

How pages in this register are compiled and graded is described under methodology; the full register is at peptides.

Last verified: 7 September 2026. Next review: on a labelling change in any covered market, on a new systematic review of the trigger question, or on any change in the anti-doping classification.