What is HCG?

What sources report

hCG is a hormone made by the human placenta and found in the urine of pregnant women.² Its alpha subunit is essentially identical to those of LH, FSH and thyroid-stimulating hormone (TSH), while the beta subunit is distinct and gives hCG its receptor and biological specificity.¹¹⁷ Pregnyl, Novarel and a Fresenius Kabi product are purified from pregnancy urine, and Ovidrel (choriogonadotropin alfa) is made by genetically modified Chinese hamster ovary cells.¹⁸¹⁸⁵ Novarel is injected into a muscle after mixing, and Ovidrel is injected under the skin from a prefilled syringe.⁸⁵

How it works

In a normal pregnancy, hCG from the placenta keeps the corpus luteum working after LH secretion falls, so estrogen and progesterone secretion continue and menstruation does not start.¹ As a medicine, its action is virtually identical to pituitary LH, with a small degree of FSH activity.¹ It stimulates the Leydig cells of the testes to make androgens and the corpus luteum of the ovary to make progesterone.¹ It can also stand in for the mid-cycle LH surge that triggers ovulation.¹ In fertility treatment, FSH-type drugs usually recruit and grow the follicles, and hCG is given when monitoring shows enough follicle development.¹

For the recombinant form, a 250 mcg injection under the skin reaches peak blood levels after about 12 to 24 hours, with a mean terminal half-life of about 29 hours.⁵

What the trials found

Weight loss

The hCG labels state that it has not been shown to be effective added therapy for obesity and has no known effect on fat mobilization, appetite or body fat distribution.¹⁸ FDA advises consumers to avoid HCG weight-loss products.⁴ The Peptides and weight loss page maps searches on this goal.

Testosterone and post-cycle use

The approved use in adult men is narrow: selected cases of hypogonadotropic hypogonadism, where a pituitary deficiency is the cause of low testicular function.¹ Wider interest comes from testosterone therapy, which lowers LH, FSH and the testosterone level inside the testes.¹⁵ In the 2005 study of 29 healthy men on weekly testosterone, adding one of three low hCG doses left testicular testosterone 25% below baseline in the lowest-dose group, 7% below in the middle group and 26% above in the highest-dose group.¹⁹

Post-cycle therapy, the attempt to restart natural testosterone after anabolic steroid use, has little evidence behind it: a 2014 review planned as a meta-analysis found no quality studies that met its criteria, and a 2026 review says no standardized treatment exists and that hCG is often used without medical supervision.²²²³ Related pages: Peptides and testosterone and Peptides and men's health.

Fertility in women

Both forms of hCG serve as the ovulation trigger in fertility care, after other drugs have grown the follicles.¹⁵ The Pregnyl label says safe ovulation induction needs regular serum estradiol tests and transvaginal ultrasound.¹ HMG is one of the drugs used to grow the follicles before the hCG trigger.²⁴ More on this goal: Peptides and women's health.

Undescended testes in boys

For prepubertal cryptorchidism not caused by an obstruction, hCG is thought to bring the testes down where descent would have happened at puberty.¹ Therapy usually starts between ages 4 and 9, and the descent is permanent in some boys but temporary in most.¹

How it compares

Recombinant and urinary hCG performed alike as an IVF trigger in the Cochrane review, but in Ovidrel's trials, application-site problems affected 14.6% of patients versus 28% with urinary hCG.²¹⁵ WADA's 2026 list puts hCG in one class with LH, gonadorelin and other GnRH analogues, and kisspeptin: testosterone-stimulating peptides, banned in males.⁷ Profiles: Gonadorelin and Kisspeptin-10. The HCG research vial is listed at HCG for sale; it is not one of the licensed hCG products.

Side effects

The Novarel label lists these reactions without rates: headache, irritability, restlessness, depression, fatigue, edema, early puberty, breast enlargement in males (gynecomastia) and pain at the injection site.⁸ Allergic reactions range from redness, hives and rash to angioedema and shortness of breath, and anaphylaxis has been reported with urinary-derived hCG.⁸

Rates come from the trials of recombinant hCG at 250 mcg:

Warnings on the labels:

• OHSS: ovarian hyperstimulation syndrome can develop rapidly after treatment and peaks about 7 to 10 days later.¹ It is more common, severe and prolonged if pregnancy occurs, women are assessed for at least two weeks after hCG, and severe OHSS may be life-threatening.¹
• Lungs and blood clots: serious lung conditions and blood clots, with or without OHSS, have been reported after gonadotropins, and in rare cases they were fatal.¹
• Multiple births: reported with all gonadotropin therapy, including hCG.¹
• Other fertility risks: ovarian torsion; more ectopic pregnancies in assisted reproduction; a higher miscarriage risk, with causality not established; and infrequent ovarian tumors after multiple stimulation drugs, with no established causal link.¹
• Men: high doses occasionally cause water and sodium retention from excess androgen production, and gynecomastia occurs sporadically.¹ Sporadic testicular tumors have been reported in otherwise healthy young men treated for secondary infertility, without an established causal link.⁸
• Fluid-sensitive conditions: because of fluid retention, hCG is used with caution in heart or kidney disease, high blood pressure, epilepsy, migraine or asthma.¹
• Boys: androgen release can cause early puberty in boys treated for undescended testes, and therapy stops if signs appear.¹
• Who should not use it: Novarel lists early puberty, prostate cancer or other androgen-dependent tumors, and prior allergy to hCG.⁸ Pregnyl's list adds primary gonadal failure in women, uncontrolled thyroid, adrenal or pituitary disease, tumors of the hypothalamus, pituitary, ovary, breast, uterus or prostate, and unexplained vaginal bleeding, among others.¹
• Pregnancy: hCG may cause fetal harm, and Pregnyl, which may be used for luteal phase support, is stopped once pregnancy is confirmed.⁸¹

Dosage information

A prescriber sets every hCG regimen: the label says it depends on the indication, the patient's age and weight, and the physician's preference.¹ The labeled schedules are written in USP units:

Novarel's reconstitution table writes the same amounts in IU.⁸ No dose is established for weight loss or for post-cycle therapy, and none of these schedules applies to a research-labeled vial or is guidance for any person.¹²² Terms such as units and concentration are explained in Peptide dosage basics.

Reconstitution and storage

Mixing and storage rules come from the licensed products' labels:

• Before mixing: Pregnyl powder is kept at controlled room temperature, 15 to 30 °C (59 to 86 °F), and Novarel at 20 to 25 °C (68 to 77 °F), with excursions allowed from 15 to 30 °C.¹⁸
• Diluent: Novarel's recommended diluent is bacteriostatic water preserved with 0.9% benzyl alcohol, a preservative linked to a fatal "gasping syndrome" in premature infants.⁸ Pregnyl comes with a 10 mL vial of water for injection containing 0.56% sodium chloride and 0.9% benzyl alcohol, labeled not for use in newborns.¹
• Mixing: Pregnyl's directions say to add 1 to 10 mL of solvent and agitate gently, without shaking, until the powder is dissolved, and not to use a discolored solution or one with particles.¹
• Concentration: in Novarel's table, 1 mL of diluent gives 10,000 IU per mL in the 10,000 unit vial or 5,000 IU per mL in the 5,000 unit vial, for a single dose; 10 mL gives 1,000 or 500 IU per mL for several doses, refrigerated in between.⁸ The Reconstitution calculator does the same arithmetic for any volume.
• After mixing: Novarel is refrigerated at 2 to 8 °C (36 to 46 °F) and used within 30 days.⁸ Mixed Pregnyl not used at once is refrigerated, and the mixed Fresenius Kabi product may be refrigerated; both are discarded after 60 days, and both labels say not to freeze or shake them.¹¹⁸
• Prefilled syringes: a patient may keep an Ovidrel syringe at room temperature, up to 25 °C (77 °F), for no more than 30 days, protected from light.⁵

These limits belong to licensed products, and no stability study of research-labeled hCG vials was found. Lab steps are in How to reconstitute a peptide vial, and storage is covered in How to store peptides.

Regulatory status

United States

FDA-licensed hCG products sold by prescription are Novarel (5,000 or 10,000 USP unit vials), Pregnyl (10,000 USP unit vials), a Fresenius Kabi product (10,000 USP unit vials) and Ovidrel (250 mcg prefilled syringes).⁸¹¹⁸⁵ Pregnyl was approved as a new drug on October 20, 1976.⁹ On March 23, 2020, these approvals were deemed biologics licenses, and FDA said such products are not eligible for the 503A and 503B compounding exemptions; it named hCG as one of four affected bulk substances.³ FDA states that hCG is not approved for use without a prescription for any purpose, and that it is not approved for weight loss.⁴

Over-the-counter "homeopathic" HCG drops, pellets and sprays sold for weight loss have not been evaluated by FDA, which says all such products are illegally marketed; FDA and FTC sent seven joint warning letters to firms selling them.² A 2011 letter adds that HCG cannot be a dietary supplement, because FDA knows of no evidence it was marketed as one before Pregnyl's approval.⁹

In an August 24, 2026 warning letter to a different online peptide seller, which did not name hCG, FDA wrote that evidence from the seller's website showed its "research use only" products were intended as drugs for human use.²⁵ Among the states, New York lists chorionic gonadotropin in Schedule III of its controlled substances law.²⁶

Sport and other countries

The WADA Prohibited List in force from January 1, 2026 bans chorionic gonadotrophin in males under S2.2.1, testosterone-stimulating peptides, at all times and as a non-Specified Substance.⁷ In the European Union, the recombinant hCG Ovitrelle has held an EU-wide marketing authorization since February 2, 2001.²⁷