hcg

a pregnancy hormone with real fertility labels and a major off-label TRT-adjunct story.

tier S · libido · legacy Pregnyl + Novarel · pre-1962 NDA

verdict

an old pregnancy hormone. fertility labels in front, decades of off-label TRT-adjunct practice behind them.

on whether HCG preserves testicular function during exogenous testosterone — this is the question TRT clinics have answered with a co-prescription for decades. exogenous testosterone shuts down LH; HCG sits in the receptor LH was hitting, so the testes keep doing their job. the receptor logic is uncontroversial. the FDA has not labeled this indication. dose and protocol live in clinician territory.

if you're here for the on-label fertility use — this is the original use, and it's old, boring, and real. ovulation induction in women, plus selected male hypogonadotropic hypogonadism and prepubertal cryptorchidism. dosing is in the Pregnyl and Novarel labels. fertility clinics, not anti-aging clinics, run the protocols that have actual outcome data behind them.

if you came in via the HCG diet — no. every controlled trial since the 1970s contradicts the diet's premise. homeopathic drops contain no measurable HCG. the weight loss is the 500-calorie diet doing what 500-calorie diets do. the FDA has issued warning letters to sellers making the weight-loss claim.

based on published evidence and disclosed clinical practice. not medical advice. dose and protocol conversations belong with a clinician who knows your bloodwork.

why S-tier

FDA-approved glycoprotein hormone in clinical use for nearly 90 years. three approved indications: female fertility, male hypogonadotropic hypogonadism, pediatric cryptorchidism. binds the LH receptor with a much longer half-life than LH itself (36 hours vs 30 minutes), which is the entire reason it is therapeutically useful. massive off-label use in TRT and male-fertility clinics. S because the clinical evidence base is deep and the FDA indications are well established.

the core tension

a pregnancy hormone that also happens to be a powerful LH mimic. that property made it the standard tool for preserving testicular function on TRT, a use case the FDA never approved but the mechanism fully supports. the off-label practice has been refined over decades.

what it is

a glycoprotein hormone the placenta makes during pregnancy. the alpha subunit is identical to LH, FSH, and TSH. the unique beta subunit carries a 24-amino-acid glycosylated tail that pushes the half-life to roughly 36 hours, versus LH's 30 minutes. sold as Pregnyl (Organon), Novarel (Ferring), and recombinant Ovidrel (EMD Serono).

what it does

binds the LH/CG receptor (LHCGR). in ovaries, triggers final follicular maturation and ovulation. in testes, signals Leydig cells to make testosterone, the same job LH does naturally. the 36-hour half-life is the whole reason it is useful where recombinant LH is not. fertility use is on-label. TRT-adjunct use is off-label, even when the mechanism is obvious.

origin

first isolated from pregnancy urine in the 1920s by Aschheim and Zondek. the same work became the first modern pregnancy test. clinical fertility use began in the 1930s, predating modern FDA review. FDA approval covers female fertility induction, male hypogonadotropic hypogonadism, and prepubertal cryptorchidism. pregnant women in parts of the world still donate urine to manufacture the urinary-extracted product.

why researchers are interested

TRT clinics built a quiet co-prescription habit on one endocrine fact: testosterone shuts down LH, and HCG can replace the testicular signal downstream. the use case is off-label. the receptor logic is why it stuck.

does it work

yes, for what the evidence actually supports. on-label fertility use is old, boring, and real. the TRT-fertility bridge has mechanistic data and decades of clinical practice behind it, but it remains off-label. the HCG diet is contradicted by every controlled trial since the 1970s. the homeopathic drops contain no meaningful HCG. the 500-calorie diet is what causes the weight loss.

claims vs the data

• triggers ovulation in fertility treatment — supported — on-label use since the 1930s. standard of care in IVF protocols as the trigger shot.
• stimulates natural testosterone production in men — supported — FDA-approved for hypogonadotropic hypogonadism. widely used off-label to preserve testicular function during TRT.
• treats undescended testicles in boys — supported — FDA-approved indication. typically used in boys 4-9 years old.
• causes weight loss — contradicted — the Simeons HCG diet from the 1950s has been repeatedly debunked in controlled trials. any weight loss comes from the extreme calorie restriction, not the HCG.
• preserves fertility on TRT — partially true — off-label but common. small clinical studies support intratesticular-testosterone and semen-parameter preservation, but this is not the labeled indication and not a guarantee.
• identical to LH — partially true — alpha subunit identical. beta subunit has a 24-aa glycosylated tail that gives HCG its longer half-life. clinically behaves as long-acting LH.
• HCG diet drops burn fat specifically — contradicted — homeopathic HCG drops contain no meaningful HCG. the "diet" is just 500 calories/day, which causes weight loss on its own.
• hCG is a weight-loss hormone — contradicted — The credible evidence sits in reproductive endocrinology, not fat loss. hCG can support intratesticular testosterone and fertility pathways in specific endocrine contexts, but the weight-loss diet claim is an old marketing artifact, not the evidence center.

key facts

• molecular formula: glycoprotein, α + β subunits
• molecular weight: ~36,700 Da (237 aa total)
• amino acids: 237 (92 α + 145 β)
• half-life: ~32-33 hours
• type: glycoprotein hormone (LH analog)
• CAS: 9002-61-3
• 1930s first clinical use
• 36 hr half-life (vs 30 min LH)
• 2020 FDA reclassified as biologic
• uneven access friction since 2020

frequently asked questions

What is HCG?

Human chorionic gonadotropin is a glycoprotein hormone naturally produced during pregnancy. Recombinant and extracted forms are FDA-approved for fertility and male hypogonadism indications. HCG mimics LH at the testicular receptor, stimulating endogenous testosterone and sperm production.

What does HCG do?

HCG stimulates testicular Leydig cells to produce testosterone and supports spermatogenesis. It is labeled for selected male hypogonadotropic hypogonadism, female fertility induction, and prepubertal cryptorchidism. TRT-adjunct use is off-label, with supportive but narrower fertility-preservation evidence.

How is HCG typically administered?

HCG is FDA-approved for specific indications including female infertility, selected male hypogonadotropic hypogonadism, and prepubertal cryptorchidism, with dosing specified in the product labels of Pregnyl and Novarel for those uses. Off-label TRT-adjunct dosing is clinician-specific and not defined by FDA labeling.

What are the side effects of HCG?

Common side effects include injection-site irritation, headache, fatigue, and fluid retention. At higher doses, gynecomastia risk from aromatization of increased testosterone is notable. In fertility use, label-level serious risks include ovarian hyperstimulation syndrome, ovarian cyst rupture, multiple gestation, and thromboembolic events.

Is HCG FDA approved?

Yes. HCG has multiple FDA-approved indications including male hypogonadism, female fertility induction, and cryptorchidism. It is classified as a prescription drug. FDA does not approve HCG for weight loss; 'HCG diet' protocols are not FDA-sanctioned.

How much does HCG cost?

Branded prescription HCG retails for $80-200 per month depending on dose. Research peptide and grey-market HCG is cheaper, though pharmaceutical-grade product quality differs from research chemical product.

related peptides

• kisspeptin-10 — upstream GnRH trigger, reproductive axis sibling

reptides grades the research record and cites the literature behind every call. research reference only; not medical advice.