HCG (Human Chorionic Gonadotropin)
Used clinically to boost fertility and restart the body's own testosterone production after a suppressive cycle. It's a glycoprotein hormone that works by mimicking LH at the testicular Leydig cell.
HCG (Human Chorionic Gonadotropin): Used clinically to boost fertility and restart the body's own testosterone production after a suppressive cycle. It's a glycoprotein hormone that works by mimicking LH at the testicular Leydig cell. HCG is a hormone that tells the testicles to keep making testosterone and sperm.
HCG is a hormone that tells the testicles to keep making testosterone and sperm. Men on testosterone therapy (TRT) use a low dose so their testicles don't shrink and they stay fertile, since TRT alone switches that signal off. It's also used to restart your own testosterone after a suppressive cycle, and for fertility. Despite old diet fads, it is not a fat-loss drug.
FDA-approved drug used to mimic LH and stimulate endogenous testosterone. Universally banned in tested sport.
Approved (multiple brand names, Pregnyl, Novarel, Ovidrel) for fertility induction in men and women, and for cryptorchidism in boys.
FDA-approved drug products containing this substance are available. Compounded versions are not FDA-approved.
Listed under S2 (Peptide Hormones, Growth Factors). Banned in male athletes only, female athletes are exempt because HCG is endogenous in pregnancy.
Yes, prescribed by reproductive endocrinology, urology, and TRT-aware providers for fertility, hypogonadism adjunct, and post-cycle support.
Who it's for
- →Men running TRT who want to preserve testicular size and fertility
- →Post-cycle users restarting their HPG axis
- →Fertility patients (under physician supervision)
What to expect
- Week 1
Testicular volume restoration begins within days when running alongside TRT.
- Week 4
PCT users see meaningful endogenous testosterone reactivation if HPG axis is intact.
- Week 8
PCT pulse usually wraps. Long-term TRT users continue indefinitely.
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How it works (mechanism)
Glycoprotein hormone that mimics luteinizing hormone (LH) at the testicular Leydig cells, directly driving intratesticular testosterone production and preserving testicular size and sperm output, the exact functions exogenous testosterone suppresses. In women it triggers ovulation, which is its fertility use.
Dosing protocol
Stacks well with
Stack essentials
Side effects
When NOT to use
- ⚠Precocious puberty
- ⚠Prostate cancer or other androgen-dependent tumor (incl. male breast)
- ⚠Prior allergic reaction to HCG (anaphylaxis risk)
- ⚠Pregnancy (HCG is the pregnancy hormone, distinct context)
Bloodwork to monitor
- • Total + free testosterone
- • Estradiol (sensitive assay)
- • LH / FSH (PCT context)
- • PSA if older
Common mistakes
- • Running it solo as a 'natural' alternative to TRT, ignores estrogen and long term axis effects
- • Skipping estrogen monitoring during PCT pulses
- • Mixing pharmacy-grade HCG with research grade product without understanding the IU-vs-mg labeling difference
- • Confusing HCG with HMG (different gonadotropin, different role)
What it actually is
HCG is human chorionic gonadotropin, a hormone made by the placenta in pregnancy. It is not a research peptide — it is an approved prescription medicine with decades of clinical use in fertility treatment and in hypogonadotropic hypogonadism specifically, rather than in hypogonadism generally. In the peptide world it is used for a specific job: keeping the testicles working, or restarting them, when testosterone therapy or a suppressive cycle has switched off the body's own signal.
It closely resembles luteinising hormone, the pituitary signal that tells testicular Leydig cells to make testosterone. When you take exogenous testosterone, the brain stops sending that signal and the testes shut down and shrink. HCG substitutes for the missing signal directly at the testis, supporting local testosterone production and testicular volume. Sperm production is not guaranteed by that alone: spermatogenesis also needs FSH, which is why fertility protocols often add an FSH-containing gonadotropin rather than relying on HCG by itself. It also drives aromatase, which is why oestrogen tends to rise alongside. The magnitude is dose-related, so lower dosing moderates it — what it does not do is eliminate the effect, which is why oestrogen gets monitored rather than assumed away.
Forms, and which is which
Urinary-derived products dosed in international units, with assured potency. Ovidrel is a recombinant choriogonadotropin alfa dosed in micrograms, not IU — a different product with a different unit, and grouping them invites a dosing error.
Verdict: The reference forms, and the units are not interchangeable.
Used in men's health clinics. Compounded preparations are not FDA-approved and quality depends on the pharmacy.
Verdict: Not an approved product; identity and potency rest on the compounder.
The labelling trap matters here: pharmacy HCG is dosed in IU and research vials are often labelled in mg, and the two are not interchangeable. Getting that conversion wrong is a large dosing error.
Verdict: Unverified, and with a specific unit-conversion hazard.
Contains FSH activity as well as LH activity. Used in fertility protocols where sperm production needs more than the LH signal. Frequently confused with HCG and not a substitute.
Verdict: A different gonadotropin for a different purpose.
What it is claimed to do, graded
Standard clinical practice with supporting human data, though the trial base for this specific adjunct use is far smaller than the overall gonadotropin literature implies.
An approved indication with a substantial evidence base. Non-obstructive azoospermia is a different population with its own separate and weaker literature, and the two should not be read together.
Standard clinical practice and widely used, though the specific post-cycle protocols circulating in this space are not what the trials tested.
The HCG diet is the origin of this claim. FDA has explicitly stated HCG is not effective for weight loss and requires that labelling, and controlled trials found the effect was entirely the 500-calorie diet it was paired with.
It can raise testosterone in men with an intact testicular response, but it does so while raising oestrogen and it does not suit everyone. Framing it as a 'natural' alternative understates what it does to the axis.
Grades describe how much human evidence exists for that specific claim, not whether it will work for you or whether it is safe.
Pros and cons
- • An approved medicine with an enormous clinical evidence base, over 400 indexed randomised-trial records
- • Solves a specific real problem — testicular shutdown on testosterone therapy — that nothing else solves as directly
- • Preserves fertility, which matters more to people than they expect it to
- • Prescribing information, monitoring and interactions are genuinely known
- • Raises oestrogen through aromatase, and that has to be monitored rather than assumed away
- • The IU versus mg labelling difference between pharmacy and research supply is a real dosing hazard
- • The weight-loss use is discredited and FDA-flagged, and still widely sold
- • Frequently confused with HMG, which does a different job
- • Anaphylaxis has been reported, so a prior reaction is an absolute contraindication
When to stop
- • Signs of high oestrogen: breast tenderness or tissue changes, water retention, mood swings
- • Any allergic reaction — HCG anaphylaxis is documented
- • In women using it in fertility treatment: abdominal pain or bloating, rapid weight gain, breathlessness or reduced urination — ovarian hyperstimulation syndrome is a medical emergency
- • Leg swelling or pain, chest pain or breathlessness — gonadotropins carry an arterial and venous thromboembolism risk
- • Testicular pain or swelling
- • A new prostate cancer diagnosis or a rising PSA that has not been explained
- • Vision changes or severe headache
Interactions
The intended pairing. It preserves the testicular function testosterone suppresses, and oestrogen needs watching on both.
Commonly added because HCG raises oestrogen. Over-suppressing oestrogen causes its own problems, so this needs bloodwork rather than guesswork.
Prostate cancer and male breast cancer are absolute contraindications — you would be raising the hormone that feeds them.
Combined in clinical practice at different points of the axis — HCG at the testis, the SERM on the pituitary signal. Not an approved combination protocol, and a prescriber's decision.
Used together deliberately in fertility protocols, under supervision.
Is this for you?
- • Men on testosterone therapy who want to preserve testicular function and fertility, with a prescriber
- • Men restarting the axis after a suppressive cycle, with bloodwork
- • You have prostate cancer or any androgen-dependent tumour
- • You have had an allergic reaction to HCG
- • You are taking it for weight loss — that use is not supported and FDA says so on the label
- • You will not monitor oestrogen
The one number
Sources for the claims above
- Clinical treatments for infertile men with non-obstructive azoospermia
- Drug monograph and clinical profile
- Immune roles in implantation and pregnancy
The Pepdex take
Pepdex take: HCG is the most-used peptide nobody calls a peptide. On TRT, low-dose HCG (250 IU 3x/week) preserves testicular function and fertility without meaningfully changing your TRT dose-response, the cost is acne and slightly higher estrogen. For PCT, it's one tool of three (HCG + SERM + time); HCG alone restarts the testes but not the brain, which is why solo-HCG PCTs leave people feeling flat. The IU-vs-mg confusion is real: research grade product sold as '5,000 IU' or '10,000 IU' refers to total vial activity, not dose, reconstitute carefully.
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