HCG

hCG, chorionic gonadotropin, Pregnyl, Novarel, Ovidrel/Ovitrelle (recombinant choriogonadotropin alfa), Chorionic Gonadotropin for Injection (generic, US), Gonasi, Choragon

Longevity & cellular

Awaiting medical reviewEN ES DE FR PT ZH+ Follow for updates

Note on this profile. HCG is an approved prescription medicine in essentially every country for fertility treatment and some hormonal conditions. Use alongside testosterone therapy, for "post-cycle" recovery, or for weight loss is off-label — and the FDA has stated plainly that HCG does not work for weight loss and is not approved for it. Grey-market and compounded HCG have additional identity and sterility risks. This page explains the published science.

Summary

Class: Naturally occurring glycoprotein hormone (~37 kDa; an α-subunit shared with LH, FSH and TSH, plus a unique β-subunit of 145 amino acids); urinary-derived (Pregnyl, Novarel) or recombinant (Ovidrel)
Mechanism: Acts as a long-lasting stand-in for LH at the LH/CG receptor: in men it drives the testes to make testosterone and supports sperm production; in women it triggers final egg maturation and ovulation and supports the corpus luteum
Routes studied: Intramuscular (traditional); subcutaneous (now standard for most uses)
Dose range reported: Label (US): ovulation induction 5,000–10,000 IU once, one day after the last follicle-stimulating drug; recombinant 250 µg (~6,500 IU) once. Male hypogonadotropic hypogonadism: 500–1,000 IU three times weekly for 3 weeks then twice weekly for 3 weeks, or 1,000–2,000 IU three times weekly, or 4,000 IU three times weekly for 6–9 months then 2,000 IU three times weekly for 3 months (several label schedules). Prepubertal cryptorchidism: 4,000 IU three times weekly for 3 weeks, or other schedules. With TRT (off-label, studies): 250–500 IU every other day or twice weekly (Coviello 2005; Hsieh 2013). Community "PCT": 500–1,000 IU every other day for 2–3 weeks, or similar
Half-life: Biphasic: roughly 6–11 hours initially then ~24–36 hours; a dose remains detectable for 7–10 days
Storage: Lyophilised: room temperature (15–30 °C) or refrigerated per label, protect from light. Reconstituted: refrigerate and use within 30 days (Novarel) or 60 days (Pregnyl, when reconstituted with bacteriostatic diluent) per labels; recombinant pens refrigerated, single use
Regulatory status: Approved medicine worldwide for fertility and hormonal indications; not approved for weight loss; compounding of HCG restricted in the US since 2020 (biologic reclassification)

Doses are as reported in studies or by the community — never recommendations.

1What it is

HCG is a hormone the placenta makes from the first days of pregnancy; it is the hormone that pregnancy tests detect. Its job is to tell the ovary's corpus luteum to keep producing progesterone so the pregnancy continues. Structurally it is almost identical to LH, the pituitary hormone that drives the testes and ovaries, but it carries extra sugar chains that let it last around a day in the blood instead of an hour. That makes it a convenient injectable substitute for LH.

Pharmaceutical HCG is either purified from the urine of pregnant women (Pregnyl, Novarel, generic chorionic gonadotropin — in use since the 1930s) or made by recombinant DNA technology (Ovidrel/Ovitrelle, approved 2000). Approved uses are: triggering ovulation in fertility treatment; treating hypogonadotropic hypogonadism in men; and undescended testes in boys. Off-label it is widely used with testosterone therapy to preserve testicular size and fertility, as "post-cycle therapy" after anabolic steroid use, and — notoriously — in the "HCG diet", which has been tested repeatedly and does not work.

2How it's thought to work

LH/CG receptor on Leydig cells (men). stimulates testosterone synthesis inside the testis. Intratesticular testosterone is normally 50–100 times blood levels and is required for sperm production; exogenous testosterone abolishes it by switching off LH, and HCG restores it.

LH/CG receptor on ovarian cells (women). a single large dose mimics the natural LH surge, completing egg maturation and causing ovulation about 36–40 hours later; smaller repeated doses support progesterone production by the corpus luteum.

Oestradiol. testicular stimulation also raises oestradiol via aromatase, which explains some side effects in men.

Cryptorchidism. stimulated testosterone may promote testicular descent in some boys.

Weight loss. no plausible mechanism; the "HCG diet" effect comes entirely from its 500 kcal/day restriction.

Stands in for LH at the LH/CG receptor: in the testes it drives testosterone production; in the ovary it triggers ovulation and supports the corpus luteum.Schematic — not to scale

3What the research shows

Triggering ovulation in assisted reproduction

Decades of and Cochrane reviews; urinary and recombinant HCG are equivalent for live birth (Youssef 2016, Cochrane). HCG trigger is the standard of care, with GnRH-agonist or kisspeptin triggers used where ovarian hyperstimulation syndrome is a concern because HCG's long increases OHSS risk. [4]

Graded A/B

Male hypogonadotropic hypogonadism

HCG alone restores testosterone and often sperm production in men whose pituitary is the problem; adding FSH improves sperm output when needed. Supported by many cohort studies and small randomised comparisons (Liu 1988; Büchter 1998, Eur J Endocrinol; Rastrelli 2014 review). [5]

Graded A (small)

Preserving intratesticular testosterone and sperm production on testosterone therapy

In a randomised study, men given testosterone enanthate plus 125, 250 or 500 IU HCG every other day maintained intratesticular testosterone in a dose-dependent fashion, whereas testosterone alone suppressed it by 94% (Coviello 2005, J Clin Endocrinol Metab). A retrospective series of 26 men on TRT plus 500 IU HCG every other day reported no azoospermia over a year (Hsieh 2013, J Urol). Small but controlled; this is the basis for off-label use with TRT. [1][2]

Recovery after anabolic steroid use

Case series and small cohorts report HCG restores testosterone and spermatogenesis in steroid-induced hypogonadism, often with clomiphene or FSH (Wenker 2015, J Sex Med). No RCT; "PCT" protocols are community-derived. [7]

Graded A (modest, declining use)

Undescended testes in boys

RCTs and meta-analyses show HCG achieves descent in roughly 20–25% of cases vs ~4% with placebo, less than surgery, with concerns about effects on germ cells; most guidelines now recommend surgery (Pyörälä 1995, J Clin Endocrinol Metab; Henna 2004, Pediatr Surg Int). [6]

Graded A (negative)

Weight loss

Multiple double-blind RCTs and a meta-analysis found no difference between HCG and placebo injections in weight loss, fat distribution, hunger or wellbeing when both groups followed the same diet (Lijesen 1995, Br J Clin Pharmacol — review of 24 studies; Stein 1976; Bosch 1990). The FDA requires HCG labels to state it has no effect on weight loss. [3]

Erectile function, libido, mood in men on TRT

Community reports; not studied in trials.

4Reported side effects and interactions

Literature-reported

Literature (labels and trials). headache, irritability, restlessness, depression, fatigue, oedema, injection-site pain; gynaecomastia and breast tenderness (via oestradiol) in men; precocious puberty signs in boys; in women ovarian hyperstimulation syndrome (abdominal pain, bloating, rapid weight gain, in severe cases fluid shifts and thrombosis), multiple pregnancy, ovarian cysts. Rare: arterial thromboembolism (reported with fertility use), hypersensitivity. HCG can produce a false-positive pregnancy test for up to about 10 days.

Community-reported

Community-reported (men). increased testicular size and sensation, raised libido, water retention, acne, mood changes, breast tenderness or gynaecomastia (sometimes managed with aromatase inhibitors, another off-label step), anxiety; some report testicular ache after higher doses.

Theoretical. long-term, high-dose HCG may desensitise Leydig cells; stimulating testosterone and oestradiol is undesirable in prostate or breast cancer and in boys with androgen-sensitive conditions; HCG is itself a tumour marker (germ-cell tumours), so dosing can confuse cancer monitoring. Grey-market product: HCG is a large glycoprotein that is biologically sourced and cannot be synthesised like a small peptide, so counterfeit or substituted vials are a particular concern.

Interactions. none pharmacologically significant on labels; combined use with testosterone, aromatase inhibitors, SERMs or FSH is common and intentional in protocols. Immunoassays for LH may cross-react.

Markers researchers commonly monitor

Marker	Why it's watched
Total testosterone	the primary effect in men; samples timed consistently relative to injections, as levels peak 2–3 days after a dose.
Oestradiol (sensitive assay)	rises with testicular stimulation and drives breast and water-retention effects.
LH and FSH	expected to fall further on HCG (it mimics LH, so the pituitary sees high androgen and shuts off); a rising LH after stopping is the sign of axis recovery in "PCT" contexts.
Semen analysis	when fertility preservation or recovery is the aim.
Haematocrit and PSA	standard whenever testosterone is being raised.
Serum β-hCG	confirms the product is active and clears within ~10 days; also relevant because it is a tumour marker.
In women: oestradiol, progesterone and ultrasound follicle tracking under fertility supervision

Free for everyone. Safety information is never behind a paywall.

5Reconstitution and handling

Urinary HCG comes as a 5,000 or 10,000 IU vial with a vial (sterile or ). Doses are in international units, not milligrams — the calculator has an IU mode. After , refrigerate and keep within the label's beyond-use period (30–60 days depending on diluent). Recombinant pre-filled syringes or pens need no preparation.

Open in calculator, pre-loaded →

6Commonly studied alongside

Testosterone (the main off-label context); FSH or menotropins (when sperm production is the goal); clomiphene, enclomiphene, tamoxifen (in recovery protocols); anastrozole (community use to control oestradiol — off-label); gonadorelin and kisspeptin (upstream alternatives).

Informational cross-links. Not stack recommendations.

7Regulatory status by region

Region	Status (checked —)
United States	FDA-approved (Pregnyl, Novarel, generic chorionic gonadotropin; Ovidrel) for ovulation induction, male hypogonadotropic hypogonadism and prepubertal cryptorchidism. Reclassified as a biologic in March 2020, which ended routine 503A compounding; labels must state it is not effective for weight loss
European Union	Authorised (Pregnyl and national brands; Ovitrelle centrally authorised 2001); prescription-only
United Kingdom	MHRA-licensed (Pregnyl, Ovitrelle, Gonasi); prescription-only
Australia	TGA-registered (Pregnyl, Ovidrel); Schedule 4
South Africa	SAHPRA-registered (Pregnyl and others); prescription-only †
Sport (WADA)	Prohibited in males only (S2 — chorionic gonadotropin and LH and their releasing factors); not prohibited in females

8Open questions

The lowest HCG dose that preserves spermatogenesis on TRT, and whether twice-weekly dosing is enough.
Long-term Leydig cell response to years of HCG stimulation.
Whether HCG offers anything over clomiphene/enclomiphene for men wanting to raise testosterone while preserving fertility.
Standardised "post-cycle" protocols — none have been tested in trials.

9References

1Coviello AD et al. (2005). Low-dose human chorionic gonadotropin maintains intratesticular testosterone in normal men with testosterone-induced gonadotropin suppression. J Clin Endocrinol Metab. PubMed · DOI
2Hsieh TC et al. (2013). Concomitant intramuscular human chorionic gonadotropin preserves spermatogenesis in men undergoing testosterone replacement therapy. J Urol. PubMed · DOI
3Lijesen GK et al. (1995). 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. PubMed · DOI
4Youssef MA et al. (2016). Recombinant versus urinary human chorionic gonadotrophin for final oocyte maturation triggering in IVF and ICSI cycles. Cochrane Database Syst Rev. PubMed · DOI
5Büchter D et al. (1998). 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. PubMed · DOI
6Pyörälä S, Huttunen NP, Uhari M (1995). A review and meta-analysis of hormonal treatment of cryptorchidism. J Clin Endocrinol Metab. PubMed · DOI
7Wenker EP et al. (2015). The use of HCG-based combination therapy for recovery of spermatogenesis after testosterone use. J Sex Med. PubMed · DOI
8Pregnyl / Novarel / Ovidrel US prescribing information (current labels). PubMed
9FDA (2020). Statement on transition of biological products, including chorionic gonadotropin, to BLA regulation. PubMed

References are being resolved to PubMed/DOI identifiers; links search PubMed for the citation until then.

† Being confirmed by our reviewers against current sources.

10Community

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Self-reported side effects Phase 2

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11Page history

25 Oct 2026Profile published — awaiting medical review

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