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Prescription hormoneHuman trialsFDA approved

HCG

Human chorionic gonadotropin

Last reviewed October 27, 2026 · 22 sources · Written for general readers · Compare with another compound →

The bottom line

HCG is a real, FDA approved prescription drug for certain fertility problems, undescended testicles in boys, and low testosterone caused by the pituitary gland. It does not help weight loss: controlled trials found it worked no better than placebo, and FDA says every HCG diet product sold over the counter is illegal. Its use alongside testosterone to protect fertility rests on small studies, and its approved uses carry real risks, including blood clots and ovary overstimulation.

Where the evidence stands

What it is

HCG is a hormone the placenta makes during pregnancy. It is built from two protein chains, called alpha and beta. Because it is a large protein and not a single small molecule, there is no simple formula or sequence to list here.[1]

In the United States, HCG is a prescription injection. FDA approved brands include Pregnyl, Novarel and Ovidrel (choriogonadotropin alfa). Pregnyl, for example, is purified from the urine of pregnant women.[1][2][3]

The approved uses are undescended testicles in young boys when nothing is physically blocking them, low testosterone in men caused by a pituitary problem, and helping some women who do not ovulate to release an egg. Ovidrel is also approved to finish egg maturation during IVF.[1][3]

HCG is also famous for the HCG diet, a very low calorie plan paired with HCG shots or drops. FDA says there are no FDA approved HCG products for weight loss.[4]

Name
HCG (Human chorionic gonadotropin)
Other names
hCG, chorionic gonadotrophin, Pregnyl, Novarel, Ovidrel (choriogonadotropin alfa)
Type
Prescription hormone

What it does in the body

HCG is made by the placenta in early pregnancy. It acts on the same receptor as luteinizing hormone (LH), the pituitary signal that tells the ovaries and testes to work, so it can stand in for LH.[1]

This is the biology, area by area. A change measured in the body, like a higher blood level, does not always mean a person feels a benefit. The claims check below covers that.

Testes and testosterone

Well established

HCG tells Leydig cells in the testes to make testosterone.[1] When healthy men took testosterone shots for three weeks, testosterone inside the testes fell 94% with placebo, while HCG shots kept it from crashing.[5] Across 41 studies of men with pituitary hormone loss, HCG based treatment raised blood testosterone and testicle size.[6]

Sperm production

Measured in people

In a 2024 analysis of 41 studies with 1,673 men whose brains or pituitaries made too little LH and FSH, about 78% made at least some sperm after a median of 18 months, but only about 15% reached the higher counts that usually make natural pregnancy likely. HCG combined with FSH worked better than HCG alone.[6]

Ovaries and ovulation

Well established

HCG mimics the natural LH surge that releases a mature egg from the ovary.[1] In Ovidrel's approval trials, about 92% of 99 women who did not ovulate on their own released an egg after it.[3]

Early pregnancy

Well established

After ovulation, HCG keeps the corpus luteum, the small gland left behind in the ovary, making progesterone and estrogen, the hormones that support an early pregnancy.[1]

Testicle descent in boys

Measured in people

The extra male hormones made under HCG can help undescended testicles move down, though this often reverses after treatment stops.[1] In pooled randomized trials of 872 boys, testicles came down in about 19% with HCG versus 4% with placebo, while a 2018 analysis of 7 trials, only 2 of which compared HCG with placebo in 31 boys, found HCG no better than placebo.[7][8]

Fat and appetite

Measured in people

HCG has no proven effect on body fat or hunger. In a double blind trial, people dieting with HCG shots lost the same weight and had the same hunger as people dieting with placebo shots.[9] A review of 24 trials found HCG did not shift fat or curb hunger.[10]

Breasts, mood and other effects

Well established

The label lists breast growth in males, headache, irritability, restlessness, depression, tiredness, fluid swelling and pain where the shot is given. In boys it can start puberty early.[1]

How it works

HCG acts a lot like luteinizing hormone (LH), the pituitary signal that tells the ovaries and testes to work.[1]

  • In men, it tells Leydig cells in the testes to make testosterone and other male hormones.[1]
  • Testosterone taken from outside shuts down the body's own LH, and testosterone inside the testes then falls sharply. HCG can stand in for the missing LH signal.[5]
  • In women, it can stand in for the natural LH surge that releases an egg, and it keeps the corpus luteum (the gland left after ovulation) making progesterone.[1]
  • In boys with undescended testicles, the extra male hormones can help the testicles move down, though this often reverses after treatment stops.[1]

These actions are well established and are described on the FDA approved labels.

What the research shows

We keep animal and human evidence apart. A result in animals is a reason to study something in people, not proof that it works in people.

Animal and lab studies

Not the main evidence for this drug

  • HCG is a human hormone with decades of human use and FDA approved labeling, so the key evidence comes from people, not animals.[1]

Limit: Animal studies add little to what human trials and the labels already show.

Human studies

Works for approved uses, fails for weight loss

  • Weight loss: the FDA approved label states that HCG has not been shown to help treat obesity, does not boost weight loss beyond cutting calories, and does not reduce hunger.[1]
  • Weight loss trial: in a 1977 randomized, double blind trial, people dieting with HCG shots lost the same weight as people dieting with placebo shots, with no difference in hunger, mood or body measurements.[9]
  • Weight loss review: a 1995 analysis of 24 trials found no scientific evidence that HCG works for obesity. Of the 12 better quality trials, only one called it useful, and HCG did not shift fat, curb hunger or improve wellbeing.[10]
  • Fertility in women: in Ovidrel's approval trials, about 35% of women having IVF had a clinical pregnancy per cycle, and in 99 women who did not ovulate on their own, about 92% ovulated and 22% became pregnant. Results matched urine based HCG.[3]
  • Lab made versus urine based HCG: a 2016 Cochrane review of 18 trials with 2,952 women having IVF found no clear difference in live births or ovary overstimulation between the two.[11]
  • Men on testosterone: in a 2005 randomized trial, 29 healthy men got weekly testosterone shots plus placebo or HCG shots for three weeks. With placebo, testosterone inside the testes fell 94%. With HCG it fell less, and with the largest of three HCG amounts it ended 26% above the starting level.[5]
  • Fertility on testosterone therapy: a review of records from 26 men, average age 36, using testosterone plus HCG shots into a muscle found that sperm counts held steady over about six months, none lost all sperm, and 9 fathered a pregnancy. There was no comparison group.[13]
  • Pituitary or brain related low hormones in men: a 2024 analysis pooled 41 studies with 1,673 men, average age 25. After a median of 18 months of HCG alone or HCG plus FSH, 78% had some sperm, 55% passed a low threshold and only 15% reached the higher counts linked with natural pregnancy. Adding FSH gave more sperm than HCG alone.[6]
  • In a German clinic series of 42 such men, HCG combined with HMG (or a hormone pump) brought sperm in 54 of 57 treatment courses and pregnancy in 26 of 36 courses aimed at it.[12]
  • Men with symptoms but normal testosterone: in a records review of 20 men treated with HCG alone for a median of 8 months, average testosterone rose about 44%, half reported feeling better, and no side effects were reported.[15] In 31 similar men, most reported better libido and erections, with no blood clots and no change in blood count, blood sugar or prostate tests.[16] Neither study had a placebo group.
  • Undescended testicles: a 1995 analysis of 33 reports with 3,282 boys found that in randomized trials, testicles came down in about 19% of boys given HCG versus 4% with placebo.[7] A 2018 analysis of 7 randomized trials concluded HCG was no more effective than placebo, but only 2 of those trials, with 31 boys, compared HCG with placebo directly.[8]
  • Recovery after steroid use: a 2025 review says HCG is used to restart sperm production in men whose sperm stopped after testosterone or anabolic steroids, but controlled long term studies are lacking.[14]

Limit: Approved uses rest on long clinical experience and approval trials. Use with testosterone, after steroids or in men with normal testosterone rests on small or uncontrolled studies, and the weight loss trials, though old, all agree it adds nothing to a diet.

Claims check

The most common claims about this compound, and what studies actually found. Verdicts rate the evidence, not whether you should use it.

Melts fat on the HCG diet

No benefit in trials so far

A double blind trial found people on HCG shots lost the same weight as those on placebo shots while following the same diet.[9] A review of 24 trials found no evidence it works for obesity.[10] The FDA label says it does not add weight loss beyond calorie cutting.[1]

Curbs hunger while dieting

No benefit in trials so far

The 1977 trial found no difference in hunger between HCG and placebo.[9] The 1995 review and the FDA label also say it does not reduce hunger.[10][1]

Burns stubborn fat and reshapes the body

No benefit in trials so far

In the double blind trial, body measurements changed the same way with HCG and placebo.[9] The 1995 review found HCG did not redistribute fat.[10]

Triggers ovulation for fertility treatment

Shown in people

In randomized trials for Ovidrel's approval, about 92% of 99 women who did not ovulate on their own released an egg, and IVF pregnancy rates matched urine based HCG.[3] A Cochrane review of 18 trials with 2,952 women found lab made (recombinant) and urine based HCG gave similar live birth rates.[11] Inducing ovulation is an FDA approved use.[1]

Raises testosterone in men with pituitary problems

Shown in people

HCG is FDA approved for low testosterone caused by a pituitary problem because it drives the testes to make testosterone.[1] A 2024 analysis of 41 studies found HCG based treatment raised testosterone and testicle size in men with pituitary hormone loss.[6]

Restores sperm in men with pituitary hormone loss

Mixed results

Across 41 studies and 1,673 men, about 78% made some sperm with HCG based treatment, but only about 15% reached higher counts, and adding FSH worked better than HCG alone.[6] In a German series of 42 men, HCG with HMG brought sperm in 54 of 57 courses.[12] Most studies had no comparison group.

Protects fertility and testicle function on testosterone

Mixed results

In a three week randomized trial of 29 healthy men, HCG kept testosterone inside the testes from crashing during testosterone shots.[5] A records review of 26 men on testosterone plus HCG found stable sperm counts over about six months, but had no comparison group.[13] No large controlled trial has tested pregnancy rates.

Restarts natural hormones after a steroid cycle

Mixed results

Doctors use HCG to restart sperm production after testosterone or steroid use, but a 2025 review notes that controlled long term studies are lacking, so the evidence is mostly case reports and clinic experience.[14]

Boosts libido and energy in men with normal testosterone

Mixed results

In a records review of 20 men with symptoms but normal testosterone, HCG alone raised average testosterone by about 44% and half reported feeling better.[15] In another records review of 31 such men, 80% said libido improved and 86% said erections improved.[16] Neither study had a placebo group, so expectation could explain much of this.

Known risks and side effects

  • Dangerous for weight loss. FDA has received reports of serious problems in people using HCG shots for weight loss, including blood clots in the lungs, depression, stroke type problems, cardiac arrest and death.[4]
  • Starvation level diets. HCG diets pair the product with a very low calorie diet, which raises the risk of gallstones, mineral imbalances and irregular heartbeat. FDA says such diets need medical supervision.[4]
  • Ovary overstimulation, multiples and clots. In Ovidrel's trials, ovarian hyperstimulation syndrome (ovaries swell and leak fluid) occurred in about 2 to 3% of women, and about 31% of IVF births were twins or more. Blood clots in arteries and burst ovarian cysts are also listed.[3][1]
  • Injection site, puberty and other effects. About 14 to 16% of women in Ovidrel trials had injection site problems such as pain or bruising.[3] In boys HCG can trigger early puberty, and reviewers of treatment for undescended testicles have flagged possible serious side effects.[1][17] Other reported effects include headache, mood changes, breast growth in males and serious allergic reactions.[1]
  • Illegal online products. FDA says every drug product claiming to contain homeopathic HCG is illegally marketed. These drops, pellets and sprays have never been checked by FDA for safety or effectiveness.[4]

Regulatory status

Today: HCG is an FDA approved prescription drug, now regulated as a licensed biological product, and compounding pharmacies may not make their own versions.[2][18] No HCG product is approved for weight loss.[4] The World Anti Doping Agency (WADA) bans it in male athletes at all times, on both the 2026 list and the 2027 list that starts January 1, 2027.[19][20]

  1. FDA and the Federal Trade Commission (FTC) sent joint warning letters to seven companies selling homeopathic HCG weight loss drops, pellets and sprays, calling them unapproved and misbranded drugs.[4][21]
  2. Approved HCG products were moved from drug approvals to biologics licenses. From that date, HCG no longer qualified for the usual compounding pharmacy exemptions.[2][18]
  3. After inspecting a compounding pharmacy, FDA wrote that HCG made there was an unapproved biological product that compounders are not allowed to make under the compounding exemptions.[22]
  4. The 2026 WADA Prohibited List took effect. It bans chorionic gonadotrophin in males, in and out of competition.[19]
  5. The 2027 WADA Prohibited List takes effect and keeps chorionic gonadotrophin banned in males.[20]

Sources

  1. Organon USA Inc. Pregnyl (chorionic gonadotropin for injection, USP) prescribing information. U.S. Food and Drug Administration. 2011. FDA label
  2. U.S. Food and Drug Administration. List of Approved NDAs for Biological Products That Were Deemed to be BLAs on March 23, 2020. FDA list
  3. EMD Serono, Inc. Ovidrel (choriogonadotropin alfa injection) prescribing information. DailyMed, U.S. National Library of Medicine. Revised December 2023. DailyMed
  4. U.S. Food and Drug Administration. Questions and Answers on HCG Products for Weight Loss. FDA
  5. Coviello AD, Matsumoto AM, Bremner WJ, Herbst KL, Amory JK, Anawalt BD, et al. Low-dose human chorionic gonadotropin maintains intratesticular testosterone in normal men with testosterone-induced gonadotropin suppression. J Clin Endocrinol Metab. 2005;90(5):2595-2602. PMID 15713727
  6. Muir CA, Zhang T, Jayadev V, Conway AJ, et al. Efficacy of Gonadotropin Treatment for Induction of Spermatogenesis in Men With Pathologic Gonadotropin Deficiency: A Meta-Analysis. Clin Endocrinol (Oxf). 2025;102(2):167-177. PMID 39445789
  7. Pyörälä S, Huttunen NP, Uhari M. A review and meta-analysis of hormonal treatment of cryptorchidism. J Clin Endocrinol Metab. 1995;80(9):2795-2799. PMID 7673426
  8. Wei Y, Wang Y, Tang X, Liu B, et al. Efficacy and safety of human chorionic gonadotropin for treatment of cryptorchidism: A meta-analysis of randomised controlled trials. J Paediatr Child Health. 2018;54(8):900-906. PMID 29655188
  9. Greenway FL, Bray GA. Human chorionic gonadotropin (HCG) in the treatment of obesity: a critical assessment of the Simeons method. West J Med. 1977;127(6):461-463. PMID 595585
  10. Lijesen GK, Theeuwen I, Assendelft WJ, Van Der Wal G. The effect of human chorionic gonadotropin (HCG) in the treatment of obesity by means of the Simeons therapy: a criteria-based meta-analysis. Br J Clin Pharmacol. 1995;40(3):237-243. PMID 8527285
  11. Youssef MA, Abou-Setta AM, Lam WS. Recombinant versus urinary human chorionic gonadotrophin for final oocyte maturation triggering in IVF and ICSI cycles. Cochrane Database Syst Rev. 2016;(4):CD003719. Cochrane CD003719
  12. Büchter D, Behre HM, Kliesch S, Nieschlag E. Pulsatile GnRH or human chorionic gonadotropin/human menopausal gonadotropin as effective treatment for men with hypogonadotropic hypogonadism: a review of 42 cases. Eur J Endocrinol. 1998;139(3):298-303. PMID 9758439
  13. Hsieh TC, Pastuszak AW, Hwang K, Lipshultz LI. Concomitant intramuscular human chorionic gonadotropin preserves spermatogenesis in men undergoing testosterone replacement therapy. J Urol. 2013;189(2):647-650. PMID 23260550
  14. Al Hashimi M, Pinggera GM, Shah R, Agarwal A. Clinician's guide to the management of azoospermia induced by exogenous testosterone or anabolic-androgenic steroids. Asian J Androl. 2025;27(3):330-341. PMID 39820213
  15. Madhusoodanan V, Patel P, Lima TFN, Gondokusumo JC, et al. Human Chorionic Gonadotropin monotherapy for the treatment of hypogonadal symptoms in men with total testosterone > 300 ng/dL. Int Braz J Urol. 2019;45(5):1008-1012. PMID 31408289
  16. Zucker IJ, Rainer QC, Pai RK, Ramasamy R, et al. Efficacy and Safety of Human Chorionic Gonadotropin Monotherapy for Men With Hypogonadal Symptoms and Normal Testosterone. Cureus. 2022;14(5):e25543. PMID 35800844
  17. Thorsson AV, Christiansen P, Ritzén M. Efficacy and safety of hormonal treatment of cryptorchidism: current state of the art. Acta Paediatr. 2007;96(5):628-630. PMID 17462056
  18. U.S. Food and Drug Administration. Notice to Compounders: Changes that affect compounding as of March 23, 2020. FDA
  19. World Anti-Doping Agency. The 2026 Prohibited List, section S2.2.1. WADA 2026
  20. World Anti-Doping Agency. The 2027 Prohibited List, section S2.2.1. In force January 1, 2027. WADA 2027
  21. U.S. Food and Drug Administration and Federal Trade Commission. Joint warning letter regarding HCG Diet Homeopathic Drops. November 28, 2011. FDA/FTC letter
  22. U.S. Food and Drug Administration, Office of Pharmaceutical Quality Operations. Post inspection letter to a compounding pharmacy (Case #641286). June 30, 2023. FDA letter
Medical disclaimer

This page is educational information only. It is not medical advice and does not replace care from a licensed medical provider. Do not use this page to decide whether to take any substance. Talk to a licensed medical provider first.

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