HCG side effects on the approved label come to nine items, and the label prints no rate for any of them. The nine are headache, irritability, restlessness, depression, fatigue, edema, precocious puberty, gynecomastia and pain at the site of injection, from the NOVAREL prescribing information in DailyMed dated September 25, 2025. The same label states in capitals that HCG has no known effect on fat mobilization, appetite, sense of hunger or body fat distribution.
Three labels cover this hormone: two made from urine, NOVAREL and PREGNYL, and one recombinant product, OVIDREL. We pulled all three from DailyMed and read the adverse reaction, warning and precaution sections in full. The distance between those sections and what a diet clinic promises is what this page sets out.
HCG side effects on the Novarel label: nine items, no frequencies
The adverse reaction section of the NOVAREL label runs one sentence. It reads: “Headache, irritability, restlessness, depression, fatigue, edema, precocious puberty, gynecomastia, pain at the site of injection.” No percentages, no severity grades, no split between common and rare.
The label is specific about allergic reactions. “Hypersensitivity reactions both localized and systemic in nature, including erythema, urticaria, rash, angioedema, dyspnea and shortness of breath, have been reported,” it says, then adds that the relationship of those allergic-like events to the polypeptide hormone or to the benzyl alcohol diluent is not clear. Anaphylaxis appears in the warnings section: “Anaphylaxis has been reported with urinary-derived HCG products.”
The approved uses of the drug number three, and weight loss sits outside all of them: prepubertal cryptorchidism not due to anatomical obstruction, selected cases of hypogonadotropic hypogonadism in males, and induction of ovulation and pregnancy in anovulatory infertile women pretreated with human menotropins. The contraindications list precocious puberty, prostatic carcinoma or another androgen-dependent neoplasm, and a prior allergic reaction to HCG. A pregnancy warning sits alongside them: “HCG may cause fetal harm when administered to a pregnant woman.”
The male list: water retention at high dosages, gynecomastia called sporadic
PREGNYL (Organon, DailyMed, December 4, 2025) sorts its adverse reactions by body system, which makes the male section short and readable. Under metabolism it states that water and sodium retention appears occasionally after high dosages and is “regarded as a result of excessive androgen production.” Under reproductive system and breast disorders it states: “HCG treatment may sporadically cause gynecomastia.” One further entry follows: precocious puberty.
Sporadically is the label’s word, and it arrives without a rate. Clinic pages that sell HCG to men on testosterone put breast growth near the top of their side effect lists, while the label gives it a single sentence.
The NOVAREL precautions add a line that matters for anyone with a cardiac history. Androgens can cause fluid retention, so the label calls for caution in patients with cardiac or renal disease, epilepsy, migraine or asthma, and directs that therapy stop if signs of precocious puberty appear. A man with heart failure reading a clinic page about HCG support will not find that caution there.
One more paragraph deserves quoting in full, because it is easy to oversell in either direction: “There have been sporadic reports of testicular tumors in otherwise healthy young men receiving HCG for secondary infertility. A causative relationship between HCG and tumor development in these men has not been established.”
The one label with percentages is Ovidrel, and they are local reactions
OVIDREL (EMD Serono, DailyMed, December 28, 2023) is the recombinant product and the only one of the three with incidence tables. Its safety section covers four clinical studies that treated 752 patients, 335 of whom received the recombinant product after follicular recruitment with gonadotropins. Application site disorders appeared in 14.6 percent of that group (49 of 335) against 28 percent (92 of 328) in the urinary-derived hCG group.
The three assisted reproduction studies, covering 236 patients, tabulate the following: at least one adverse event 33.1 percent (78 patients), injection site pain 7.6 percent (18), injection site bruising 4.7 percent (11), abdominal pain 4.2 percent (10), nausea 3.4 percent (8) and vomiting 2.5 percent (6).
Allergic reactions get a different treatment in this label. Cases including anaphylaxis have been reported since market introduction, and “the causal relationship is unknown.”
Two limits apply to those figures. The patients were fertility patients under ultrasound and estradiol monitoring, so the numbers describe a monitored group. The tabulated events are mostly injection-site complaints and gastrointestinal upset, a narrower picture than the systemic list that clinic pages discuss.
The serious risk in women is ovarian hyperstimulation, and it peaks after the last shot
The PREGNYL warnings describe ovarian hyperstimulation syndrome, OHSS, as “a medical event distinct from uncomplicated ovarian enlargement” that “may progress rapidly to become a serious medical event.” The early warning signs it names are severe pelvic pain, nausea, vomiting and weight gain. The timing is the part readers tend to miss: “OHSS occurs after gonadotropin treatment has been discontinued and it can develop rapidly, reaching its maximum about seven to ten days following treatment.” Severe OHSS may be life-threatening, and the label advises assessment for at least two weeks after HCG administration.
The female adverse list on the same label includes thromboembolism in rare instances, usually tied to severe OHSS, hydrothorax, ascites, ovarian cysts prone to rupture, painful breasts, and weight gain as a characteristic of severe OHSS. Weight gain appears twice in that label: as a sign of severe OHSS and as a reason to report symptoms.
HCG side effects reported from diet clinics belong to the diet
The FDA consumer update “Avoid Dangerous HCG Diet Products,” updated July 13, 2020, describes the products: oral drops, pellets and sprays, sold online, at weight loss clinics and in some retail stores, and paired with a diet that limits calories to 500 a day. The FDA states that HCG is not approved for weight loss and is not approved for use without a prescription for any purpose.
The agency’s own list of what those diets do to people covers gallstone formation, an imbalance of the electrolytes that keep muscles and nerves working, and an irregular heartbeat. It calls such a diet dangerous and potentially fatal.
Carolyn Becker, director of the Office of Unapproved Drugs and Labeling Compliance in the FDA’s drug center, said in that update that the data do not support the marketing claims and that any lost weight comes from severe calorie restriction. The NOVAREL label states the same thing in regulatory language: “There is no substantial evidence that it increases weight loss beyond that resulting from caloric restriction.”
Four controlled trials and one meta-analysis cover the question, and each lands in the same place.
- Young, Fuchs and Woltjen, JAMA, November 29, 1976: 202 patients in a double-blind crossover, with “no statistically significant difference between those receiving HCG vs placebo during any phase of this study” at P greater than 0.1.
- Stein and colleagues, American Journal of Clinical Nutrition, September 1976: 51 women over 32 days, no statistically significant difference in weight loss, waist and hip circumference or hunger ratings.
- Bosch, Venter, Stewart and Bertram, South African Medical Journal, February 17, 1990: 40 obese women, all on a diet supplying 5,000 kilojoules a day, six weeks of injections six days a week of saline or HCG, and the HCG group “showed no advantages over those on placebo in respect of any of the variables recorded.”
- Lijesen, Theeuwen, Assendelft and Van Der Wal, British Journal of Clinical Pharmacology, September 1995: a meta-analysis of 8 controlled and 16 uncontrolled trials, in which 12 studies scored 50 or more points for method quality and one of those 12 reported HCG as a useful adjunct. The authors concluded there is “no scientific evidence that HCG is effective in the treatment of obesity.”
For anyone running a home pregnancy test, the OVIDREL label carries a separate caution: administration “may interfere with the interpretation of pregnancy tests.”
Anaphylaxis, older adults, and what the three labels do not cover
The two urinary-derived labels both state that anaphylaxis has been reported with urinary-derived HCG products, and a prior allergic reaction to HCG is a contraindication on both. The recombinant label reports allergic reactions including anaphylaxis since market introduction and declines to assign cause.
Age is a separate gap. PREGNYL’s geriatric note states: “Clinical studies of PREGNYL (chorionic gonadotropin) for injection did not include subjects aged 65 and over.” The OVIDREL label states that safety and effectiveness in geriatric patients has not been established. A man in his sixties reading a clinic page about HCG for testosterone support is reading about a group the trials skipped.
None of the three labels describes a compounded preparation, and the FDA consumer update covers the unapproved weight loss products separately from the approved injectables.
A prescription is a question for a prescriber who has your history and your labs. Our clinic directory lists practices by city, and we do not screen licenses, so check each clinic’s license with the state medical board before you book. Our compound pages cover the peptides that come up most often in clinic visits.
Frequently asked questions
Are HCG side effects dangerous?
Most of what the labels list is manageable: headache, irritability, fatigue, edema and injection-site pain. The serious entries are anaphylaxis, which both urinary-derived labels say has been reported, and ovarian hyperstimulation syndrome in women, which the PREGNYL warning calls potentially life-threatening. A 500 calorie diet adds its own risks, including gallstones, electrolyte imbalance and an irregular heartbeat.
Does HCG cause gynecomastia?
PREGNYL states that HCG “may sporadically cause gynecomastia” and gives no rate. NOVAREL lists gynecomastia among its nine adverse reactions, also without a frequency.
Is HCG approved for weight loss?
No. The FDA consumer update of July 13, 2020 states that HCG is not approved for weight loss and is not approved for use without a prescription for any purpose. The NOVAREL label states that there is no substantial evidence it increases weight loss beyond caloric restriction.
Do the injections do anything for weight loss?
Four controlled trials and one meta-analysis compared HCG with placebo and found no difference. Young and colleagues reported no statistically significant difference across 202 patients in JAMA on November 29, 1976, and Lijesen and colleagues concluded in the British Journal of Clinical Pharmacology in September 1995 that no scientific evidence supports HCG as an obesity treatment.
What are the risks of the 500 calorie diet sold with HCG drops?
The FDA lists gallstone formation, an imbalance in the electrolytes that keep muscles and nerves working, and an irregular heartbeat, and describes such diets as dangerous and potentially fatal. The agency advises people who own these products to stop using them, throw them out and stop following the dieting instructions.
How soon does ovarian hyperstimulation appear?
The PREGNYL warning states that OHSS can develop after gonadotropin treatment stops and reaches its maximum about seven to ten days later. The label advises assessment for at least two weeks after HCG administration, and severe cases may be life-threatening.
Where do the three labels sit?
All three are in DailyMed and linked below: NOVAREL dated September 25, 2025, PREGNYL dated December 4, 2025, and OVIDREL dated December 28, 2023. We read them on November 1, 2026.
Sources:
- NOVAREL (chorionic gonadotropin) for injection, prescribing information, DailyMed, September 25, 2025.
- PREGNYL (chorionic gonadotropin) for injection, prescribing information, Organon, DailyMed, December 4, 2025.
- OVIDREL (choriogonadotropin alfa) injection, prescribing information, EMD Serono, DailyMed, December 28, 2023.
- FDA, “Avoid Dangerous HCG Diet Products,” consumer update, updated July 13, 2020.
- Young RL, Fuchs RJ, Woltjen MJ, “Chorionic gonadotropin in weight control: a double-blind crossover study,” JAMA, November 29, 1976.
- Stein MR, Julis RE, Peck CC, Hinshaw W, Sawicki JE, Deller JJ, “Ineffectiveness of human chorionic gonadotropin in weight reduction: a double-blind study,” American Journal of Clinical Nutrition, September 1976.
- Bosch B, Venter I, Stewart RI, Bertram SR, “Human chorionic gonadotrophin and weight loss: a double-blind, placebo-controlled trial,” South African Medical Journal, February 17, 1990.
- 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,” British Journal of Clinical Pharmacology, September 1995.
This article is general information for people comparing peptide clinics and weight loss programs. It is not medical advice, it is not a recommendation for or against any product, and it carries no dosing guidance. Compounded preparations are not FDA-approved drugs. Talk with a licensed prescriber about your own history before starting, stopping or changing anything.