hCG (human chorionic gonadotropin)

hCG is like a master key cut for one particular door. In a fertility clinic it opens exactly that door at exactly the right moment. Bodybuilders use the same key to keep a side door propped open while testosterone does the work, which seems to work a bit in small tests. Diet sellers claim it also opens the fridge lock to stop hunger. It does not: the weight loss comes from the near-empty fridge.

hCG binds the LH/choriogonadotropin receptor (LHCGR), the same receptor used by luteinising hormone. In the ovary it triggers final egg maturation and ovulation and keeps the corpus luteum making progesterone in early pregnancy. In the testes it stimulates Leydig cells to make testosterone, which keeps testosterone levels high inside the testes and supports sperm production even when the body's own LH has been switched off by external testosterone. It has no known action that burns fat or suppresses appetite.

Research contexts. Not proven uses, and not recommendations.

Three very different stories. As a fertility drug, hCG has long clinical use and controlled trial data, and recombinant hCG (Ovitrelle) is licensed in the UK for triggering ovulation and egg maturation. Alongside testosterone treatment, the evidence is small: a randomised study of 29 healthy men (Coviello 2005) showed low-dose hCG kept testosterone inside the testes near normal while on testosterone injections, and a records review of 26 men (Hsieh 2013) found sperm counts held steady and no one stopped producing sperm. These are promising but small, short and mostly not about the bodybuilding doses and cycles used on the grey market. For post-cycle therapy after steroids there are no controlled trials. For weight loss, the evidence is clear and negative: a 1995 meta-analysis (Lijesen) of 24 trials found no evidence hCG helps weight loss, fat distribution or hunger, and the FDA says any weight lost on the hCG diet comes from severe calorie restriction, not the hCG.

• !Ovarian hyperstimulation syndrome (OHSS) is the main risk in women: in Ovitrelle trials it occurred in about 4% of patients, severe in under 0.5%, and blood clots have rarely been linked to it.
• !In men, hCG can raise oestrogen as well as testosterone and may cause gynaecomastia (breast growth) and water and sodium retention at high doses.
• !Other listed side effects include headache, irritability, restlessness, depression, fatigue, swelling and injection-site reactions, plus rare allergic reactions.
• !The "hCG diet" relies on eating around 500 calories a day; the FDA warns this can cause gallstones, electrolyte imbalance and heart rhythm problems without medical supervision.
• !hCG diet products are often sold as drops, pellets and sprays; the FDA advises consumers to avoid them and says hCG is not approved for weight loss.
• !Grey-market vials sold for TRT or post-cycle use have no quality control: identity, strength and sterility are unknown.
• !It is a Class C controlled drug in the UK, so supplying it outside the medical system is a criminal offence.

hCG is a prescription-only medicine (POM) in the UK, regulated by the MHRA. Ovitrelle (choriogonadotropin alfa, Merck Serono) holds a GB marketing authorisation (PLGB 11648/0274) for triggering final follicular maturation in assisted reproduction and triggering ovulation in women who do not ovulate regularly. Urinary hCG products such as Pregnyl have also been used in the UK, though availability has varied and some NHS formularies list them as discontinued. hCG is not licensed for weight loss, and use alongside testosterone or after steroid cycles is off-label. Chorionic gonadotrophin (HCG) and non-human chorionic gonadotrophin are Class C controlled drugs under Schedule 2 Part III of the Misuse of Drugs Act 1971, and sit in Schedule 4 Part II of the Misuse of Drugs Regulations 2001 alongside anabolic steroids. Possessing it in the form of a medicinal product is not an offence, but supplying it, possessing it with intent to supply, or producing it are offences (Class C supply and production carry up to 14 years).

1. 01
   The effect of human chorionic gonadotropin (HCG) in the treatment of obesity by means of the Simeons therapy: a criteria-based meta-analysis — Lijesen GK, Theeuwen I, Assendelft WJ, Van Der Wal G., British Journal of Clinical Pharmacology, 40(3):237-243 (1995)

   8 controlled and 16 uncontrolled trials; no scientific evidence that hCG causes weight loss, fat redistribution or reduced hunger.

2. 02
   Low-dose human chorionic gonadotropin maintains intratesticular testosterone in normal men with testosterone-induced gonadotropin suppression — Coviello AD, Matsumoto AM, Bremner WJ, et al., Journal of Clinical Endocrinology and Metabolism, 90(5):2595-2602 (2005)

   29 healthy men randomised; testosterone alone cut intratesticular testosterone by 94%, low-dose hCG kept it near normal.

3. 03
   Concomitant intramuscular human chorionic gonadotropin preserves spermatogenesis in men undergoing testosterone replacement therapy — Hsieh TC, Pastuszak AW, Hwang K, Lipshultz LI., Journal of Urology, 189(2):647-650 (2013)

   Retrospective review of 26 men on TRT plus low-dose hCG; semen parameters unchanged, no azoospermia.

4. 04
   Ovitrelle 250 micrograms/0.5 ml prefilled syringe - Summary of Product Characteristics (SmPC), electronic medicines compendium (emc), UK

   UK licensed indications (ART trigger, ovulation induction), OHSS in about 4% (severe under 0.5%), GB authorisation PLGB 11648/0274.

5. 05
   Pregnyl (chorionic gonadotropin for injection) prescribing information, Organon (US label)

   Labelled indications (cryptorchidism, male hypogonadotropic hypogonadism, ovulation induction); capitalised statement in the Indications section that hCG has not been shown to be effective for obesity; gynaecomastia and fluid retention in males.

6. 06
   Avoid Dangerous hCG Diet Products, US Food and Drug Administration, Consumer Updates (2020)

   hCG is not approved for weight loss; any loss comes from severe calorie restriction; 500-calorie diets risk gallstones, electrolyte imbalance and arrhythmias.

7. 07
   Misuse of Drugs Act 1971, Schedule 2 (Part III, Class C), legislation.gov.uk

   Lists chorionic gonadotrophin (HCG) and non-human chorionic gonadotrophin as Class C drugs.

8. 08
   The Misuse of Drugs Regulations 2001, Schedule 4 (Part II), legislation.gov.uk

   Places chorionic gonadotrophin (HCG) in Schedule 4 Part II with anabolic steroids.

9. 09
   Drugs penalties, GOV.UK

   Class C: supply and production carry up to 14 years in prison; possession of anabolic steroids for personal use is not an offence.

10. 10
    The 2026 Prohibited List (World Anti-Doping Code), World Anti-Doping Agency (2026)

    S2.2.1: chorionic gonadotrophin (CG) prohibited in males. Wording checked against the official 2026 list text as republished in the Austrian Federal Law Gazette (BGBl. III Nr. 219/2025).