Underground Biohacking
Hormonal

HCG (Human Chorionic Gonadotropin)

Chris Hallewell, founder of Underground Biohacking

By , Founder, Underground Biohacking

Last reviewed

Prescription only

HCG is a prescription hormone, not a supplement. The FDA approves it for some cases of female infertility and for hormone treatment in men. In men whose brain signal to the testicles has failed, trials show it raises testosterone, and with FSH it can start sperm production. It does nothing for fat loss. Placebo controlled trials found no extra weight loss, and the FDA says the over the counter HCG diet drops are illegally marketed.

What is HCG (Human Chorionic Gonadotropin)?

HCG stands for human chorionic gonadotropin. It is a hormone the placenta makes during pregnancy. It appears in the urine of pregnant women, which is how a home pregnancy test finds it. The FDA states that HCG is approved for select cases of female infertility and for hormone treatment in men. It is a glycoprotein, a large protein that carries sugar chains. That size matters. A molecule this big cannot survive the gut, so the approved products are injections and need a prescription. Drops, pellets and sprays sold as homeopathic HCG are not approved medicines at all. HCG works because it looks like luteinizing hormone, or LH. That is the pituitary signal telling the testes to make testosterone and the ovaries to release an egg. It locks onto the same receptor. In men that stimulates the testicles directly, so testosterone can rise while the testicles keep working. In women it can finish the maturing of an egg and trigger ovulation. That mimicry explains everything HCG does in the clinic. It also explains what it does not do: it has no direct action on fat cells, appetite or where the body stores fat.

What is HCG (Human Chorionic Gonadotropin) prescribed for?

  • In a randomised trial in men with hypogonadism (low testosterone caused by a faulty hormone signal), HCG restored testosterone as well as clomiphene did.[1]Human study
  • In men with hypogonadotropic hypogonadism who made no sperm, long term HCG combined with FSH stimulated sperm production.[2]Human study
  • In azoospermic men (men with no sperm in the ejaculate), HCG on its own normalised testosterone in most, yet they still made no sperm.[3]Human study
  • In infertile men with low testosterone, medical treatment that included HCG improved sperm concentration and testosterone.[4]Human study
  • In boys with undescended testicles, HCG raised the rate of complete testicular descent compared with controls.[5]Human study
  • In obese women on a strict diet, HCG injections beat placebo injections on nothing that was measured.[6]Human study
  • In a crossover trial of people in a weight reduction programme, HCG did no better than placebo at any stage.[7]Human study

How does HCG (Human Chorionic Gonadotropin) work?

hCG is a hormone your body makes in pregnancy. It's a protein built from two subunits joined together. Its shape closely resembles luteinising hormone, or LH, the pituitary signal that tells the gonads to make sex steroids. Both hormones dock at the same receptor, called the LH/CG receptor. It sits on the surface of Leydig cells in the testes and on ovarian cells. When hCG binds, the receptor raises cAMP inside the cell. cAMP is a messenger that switches on the steroid making machinery. So hCG works by imitating LH rather than replacing testosterone. Lab work shows hCG is the more potent of the two.

Educational reference only. Talk to a licensed clinician for any decisions on HCG (Human Chorionic Gonadotropin).

What are the side effects of HCG (Human Chorionic Gonadotropin)?

EffectHow seriousWhat to watch
Acne was the most common complaint in men treated with HCG and FSH, and some developed gynecomastia (growth of breast tissue).[2]Common, usually mildSkin breakouts, tenderness or swelling under the nipple.
In IVF, using HCG to trigger ovulation can cause ovarian hyperstimulation syndrome (OHSS), where the ovaries swell and fluid leaks into the abdomen.[8]SeriousBloating, belly pain, sudden weight gain, breathlessness. Seek urgent care.
Injection site reactions were the most common of the other adverse events recorded across trials of HCG in fertility treatment.[9]Common, mildRedness, pain or swelling where the injection was given.
Men treated with HCG as boys before surgery for undescended testicles had smaller adult testicles than those who had surgery alone.[10]Potentially long termA specialist should weigh this up before any hormonal treatment in a child.
In trials of boys with cryptorchidism the reported side effects passed off, but the long term picture was left unresolved.[5]Unknown over the long termNothing specific in the short term. The unknown is what happens years later.

Is HCG (Human Chorionic Gonadotropin) legal in 2026?

Checked on 6 August 2026. The FDA page on HCG products for weight loss is clear. It says HCG is approved for select cases of female infertility, and for hormone treatment in men. Approved HCG products come only as injections and need a prescription. It also says there are no FDA approved HCG products for weight loss. HCG has not been demonstrated to be effective therapy in the treatment of obesity, the page states. The FDA and the FTC issued joint warning letters to firms selling over the counter HCG drops, pellets and sprays labelled as homeopathic. The page states that all drug products claiming to include homeopathic HCG are illegally marketed. The FDA also reports serious adverse events from HCG injections used for weight loss, including pulmonary embolism, cardiac arrest and death.

Status checked against the primary source.

Educational reference only. Talk to a licensed clinician for any decisions on HCG (Human Chorionic Gonadotropin).

If you are considering HCG (Human Chorionic Gonadotropin)

This page does not provide dosing, cycling, stacking, or sourcing guidance for HCG (Human Chorionic Gonadotropin). The protocol conversation belongs with a licensed clinician who can review your bloodwork, history, and goals.

Where to buy HCG (Human Chorionic Gonadotropin)

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Frequently Asked Questions

What does HCG actually do in the body?
HCG copies luteinizing hormone, the pituitary signal that drives the gonads. In men it tells the testicles to make testosterone. In women it can finish the maturing of an egg so the ovary releases it. That is why fertility clinics use it, and why doctors also use it as a test of whether the testicles still respond to a signal. It has no direct action on fat cells or appetite.
Does the HCG diet work?
No. Any weight lost comes from the very low calorie diet, not the hormone. Double blind trials going back to the 1970s compared HCG injections with saline injections while everyone ate the same restricted diet. Weight loss was the same in both groups. Hunger, mood and body measurements were the same too. The FDA states plainly that HCG has not been demonstrated to be effective therapy in the treatment of obesity.
Are the HCG drops sold online the same thing?
No. The FDA has never approved an oral or homeopathic HCG product. Its page on HCG weight loss products says every drug product claiming to contain homeopathic HCG is illegally marketed. The FDA and FTC sent joint warning letters to sellers. There is a second problem. Those products come with instructions for a very low calorie diet, which the FDA links to gallstones, electrolyte imbalance and heart rhythm problems.
Can a man raise testosterone with HCG and still stay fertile?
That is the reason doctors reach for it. Standard testosterone therapy switches off the body's own signal to the testicles, and sperm production falls with it. HCG stimulates the testicles instead, so they keep working. In a randomised trial of men with hypogonadism who wanted to protect fertility, HCG raised testosterone as well as clomiphene did. In men making no sperm at all, HCG alone was often not enough and FSH was added.
Is HCG safe?
It has a long clinical record, so the risks are described reasonably well. In men, acne and breast tissue growth are the common complaints. In fertility treatment the serious risk is ovarian hyperstimulation syndrome, which can be dangerous. Injection site reactions are common. In boys, one follow up study linked HCG given before surgery to smaller adult testicles. The FDA also lists serious events reported when HCG was injected for weight loss, including clots and death.
What should I ask a doctor before considering HCG?
Start with why. Ask what is actually wrong, and whether blood tests show the problem sits in the pituitary or in the testicles, because that changes the answer. Ask what the treatment is meant to achieve, and how success will be measured. Ask what gets monitored, and how often. Ask what happens if it does not work. If fertility matters to you, say so early, because it changes the whole plan.

References

  1. 1.Habous M, et al. (2018). Clomiphene citrate and human chorionic gonadotropin are both effective in restoring testosterone in hypogonadism: a short-course randomized study. BJU international. PMID: 29772111. DOI: 10.1111/bju.14401.
  2. 2.Matsumoto AM, et al. (2008). Stimulation of spermatogenesis with recombinant human follicle-stimulating hormone (follitropin alfa; GONAL-f): long-term treatment in azoospermic men with hypogonadotropic hypogonadism. Fertility and sterility. PMID: 18930190. DOI: 10.1016/j.fertnstert.2008.07.1742.
  3. 3.Bouloux PM, et al. (2003). Induction of spermatogenesis by recombinant follicle-stimulating hormone (puregon) in hypogonadotropic azoospermic men who failed to respond to human chorionic gonadotropin alone. Journal of andrology. PMID: 12826700. DOI: 10.1002/j.1939-4640.2003.tb02712.x.
  4. 4.Lima TFN, et al. (2021). Evaluation of a serum 17-hydroxyprogesterone as a predictor of semen parameter improvement in men undergoing medical treatment for infertility. Canadian Urological Association journal. PMID: 33382370. DOI: 10.5489/cuaj.6846.
  5. 5.Bu Q, et al. (2016). The Effectiveness of hCG and LHRH in Boys with Cryptorchidism: A Meta-Analysis of Randomized Controlled Trials. Hormone and metabolic research. PMID: 27050251. DOI: 10.1055/s-0042-104059.
  6. 6.Bosch B, et al. (1990). Human chorionic gonadotrophin and weight loss. A double-blind, placebo-controlled trial. South African medical journal. PMID: 2405506.
  7. 7.Young RL, et al. (1976). Chorionic gonadotropin in weight control. A double-blind crossover study. JAMA. PMID: 792477.
  8. 8.Engmann LL, et al. (2019). Low dose human chorionic gonadotropin administration at the time of gonadotropin releasing-hormone agonist trigger versus 35 h later in women at high risk of developing ovarian hyperstimulation syndrome - a prospective randomized double-blind clinical trial. Journal of ovarian research. PMID: 30684970. DOI: 10.1186/s13048-019-0483-7.
  9. 9.Youssef MA, et al. (2016). Recombinant versus urinary human chorionic gonadotrophin for final oocyte maturation triggering in IVF and ICSI cycles. The Cochrane database of systematic reviews. PMID: 27106604. DOI: 10.1002/14651858.CD003719.pub4.
  10. 10.Taskinen S, Wikström S (1997). Effect of age at operation, location of testis and preoperative hormonal treatment on testicular growth after cryptorchidism. The Journal of urology. PMID: 9224326.

One more time, because it matters

This page exists to identify HCG (Human Chorionic Gonadotropin) and explain what the research describes. Underground Biohacking does not advise on dosage, cycling, stacking, or where to source prescription compounds. If HCG (Human Chorionic Gonadotropin) is part of your plan, that conversation belongs with a clinician who can review your labs, history, and goals. Not with a website.