HCG

What it is

HCG is not a small research peptide. It is a large hormone protein (a glycoprotein) that the placenta makes in pregnancy, and it is a licensed prescription medicine in the UK and most countries. The version in research vials is usually purified from urine or made by recombinant methods.

It acts like luteinising hormone (LH), the signal that tells the testes to make testosterone and tells the ovaries to release an egg. Doctors use it in fertility treatment, to trigger ovulation, and for some men with low testosterone caused by a pituitary problem. In the bodybuilding and TRT world it is used to keep the testes working and keep their size while on testosterone.

It has also been sold for years as a weight-loss product (the so-called HCG diet). That does not work: controlled trials show no fat-loss benefit beyond the very low calorie diet that comes with it, and regulators have warned against it.

History

HCG was identified in pregnancy urine in the late 1920s and has been used as a medicine since the 1930s, making it one of the oldest hormone drugs still in use. The HCG diet dates from the 1950s, and was tested and discredited from the 1970s onwards.

How it works

HCG binds the same receptor as LH. In men, this stimulates the Leydig cells in the testes to make testosterone and keeps intratesticular testosterone high, which supports sperm production and testicle size. In women, it triggers the final release of an egg from a ripe follicle. Because it has a much longer half-life than natural LH, it acts like a long, steady LH signal rather than natural pulses.

Dosage

• Doses are in international units (IU), not milligrams, and there is no single right dose. It depends entirely on why it is being used.
• Fertility clinics use a single trigger dose of about 5,000-10,000 IU to induce ovulation or final egg maturation, under monitoring.
• For men with hypogonadotropic hypogonadism, clinic regimens are commonly around 1,000-2,000 IU two to three times a week, adjusted using blood tests.
• Men using it alongside TRT commonly report 250-500 IU two to three times a week. This is community practice, not a licensed regimen. Higher doses are often reported to raise oestrogen and can work against you.
• Anything beyond this needs a prescriber and bloods (testosterone, oestradiol, and for fertility, semen analysis).

How it is taken

• Subcutaneous injection into belly fat with a 29-31G insulin syringe is the usual route for TRT-style use. Clinics use both SC and IM.
• Rotate sites. Inject slowly to reduce stinging.
• If you are using it for fertility, the timing of the dose matters to the hour. Follow your clinic, not a forum.

How to reconstitute

• 5,000 IU vial: add 2.5 ml of bacteriostatic water to get 2,000 IU/ml. On a 1 ml syringe that is 20 IU per unit, so 250 IU is 12.5 units and 500 IU is 25 units.
• Alternatively, 5,000 IU with 5 ml of BAC water gives 1,000 IU/ml, so 10 IU per unit and 250 IU is 25 units. More dilute makes small doses easier to measure.
• 10,000 IU vial: add 5 ml of BAC water to get 2,000 IU/ml (20 IU per unit), or 10 ml for 1,000 IU/ml (10 IU per unit). Check that the vial can hold the volume.
• Add water slowly down the inside wall and swirl gently. Do not shake; it is a large protein and is damaged by foaming.

How it should arrive

Sealed glass vial with an intact cap and a white lyophilised cake or powder. Licensed products often come with a solvent ampoule. Research vials are usually powder only and need bacteriostatic water.

How it should look once reconstituted

Clear and colourless when dissolved. Cloudiness, floating strands or flakes mean do not use it. Any foaming that does not settle suggests it was shaken.

What to expect, and when

• In men on TRT, testicular size and feel typically change within a few weeks if it is going to help.
• In men with hypogonadotropic hypogonadism, testosterone rises within days but sperm production takes about 3-6 months to rebuild, and often needs FSH added.
• Fertility triggers act within about 36-40 hours, which is why timing is exact.
• As a weight-loss aid it will not do anything, whatever the timeline.

Side effects

• Injection-site pain, redness or bruising.
• Raised oestrogen in men: breast tenderness, gynaecomastia, water retention, mood swings. This is dose-related.
• Headache, tiredness, irritability, acne.
• In women: bloating, ovarian cysts, and ovarian hyperstimulation syndrome (OHSS) in fertility treatment, which can be serious.
• It will give a positive pregnancy test for days to weeks after the last dose.

Risks

• It is a prescription-only medicine in the UK. Buying it without a prescription is unlicensed, and quality in research vials is not guaranteed. Counterfeit HCG has been found on the market, so third-party testing matters.
• In women, OHSS (fluid shifts, abdominal swelling, rarely blood clots) and multiple pregnancy are real fertility-treatment risks.
• High doses in men may desensitise the Leydig cells and cause the testes to respond less over time, according to some studies and clinical reports. This is another reason not to chase high doses.
• Using HCG alone in men is not a safe route to raising testosterone if you want to preserve fertility long term without bloods and monitoring.
• HCG is banned by WADA for male athletes (it is used to mask steroid use) and is tested for.
• Avoid in pregnancy outside of supervised treatment, and with hormone-sensitive cancers or testicular tumours.

Potential gains

• Preserving testicular size and function during TRT; some men also report better mood and libido than on testosterone alone.
• Restarting sperm production in men with pituitary-related low testosterone, usually combined with FSH.
• Triggering ovulation in assisted-fertility cycles. This is the strongest, best-evidenced use.
• Weight loss is not a gain. The HCG diet has been tested and does not work.

Other useful information

HCG and FSH products (like HMG) are standard fertility-clinic medicines, and your best source of safe use is a clinic or private endocrinologist who will also order bloods. If you are on TRT and fertility matters to you, say so to the prescriber: some men need HCG and FSH, and others do better coming off testosterone. Most men on TRT find HCG at the low end (250-500 IU) is plenty, and more is not better.