HCG is a natural hormone made during pregnancy that signals the body to keep producing testosterone and to support reproduction. Used medically, it can stimulate testosterone in men, trigger ovulation in women undergoing fertility treatment, and help undescended testes in young boys - all FDA-approved uses backed by decades of clinical evidence. Importantly, the FDA label states HCG has no effect on fat mobilization or body-fat distribution and is not effective for weight loss.
Human chorionic gonadotropin is an FDA-approved glycoprotein gonadotropin that acts as a potent LH mimetic by binding the LHCGR on Leydig cells and granulosa/luteal cells. Its three approved indications - hypogonadotropic hypogonadism in males, prepubertal cryptorchidism, and ovulation induction in anovulatory women - are FDA-labeled. Off-label TRT fertility preservation (500 IU SC EOD) rests on Grade B retrospective data; PCT use is Grade D. Its prolonged elimination half-life (~32-33 h vs ~20 min for endogenous LH) makes it pharmacologically distinct from recombinant LH.
HCG is a ~237-amino-acid, extensively O- and N-glycosylated heterodimer (~37.9 kDa; ~31% carbohydrate) binding LHCGR with higher Gs/Gq coupling efficacy than human LH. It is preferentially routed into Rab5-positive early endosomes after beta-arrestin-2 recruitment, sustaining cAMP and intracellular Ca2+ for prolonged steroidogenesis. Structural homology with TSH confers weak thyrotropic cross-reactivity, clinically significant mainly above ~200 IU/mL serum HCG. The beta-CTP of the beta-subunit extends half-life and reduces thyrotropic potency roughly tenfold versus LH.
HCG is one of the few molecules in this atlas that is a fully FDA-approved prescription drug with decades of randomized human data. The engine therefore treats its approved reproductive/endocrine indications as high-grade, while flagging the popular off-label uses (TRT fertility preservation, PCT, and especially "weight loss") at their true, much lower, evidence tiers.
HCG works mainly by copying luteinizing hormone (LH). It plugs into the same receptor on the cells that make testosterone (in men) and progesterone (in women), switching on hormone production - but it lasts far longer in the body than natural LH.
HCG's effects converge on one receptor - the LHCGR - but it differs from native LH in important ways: a much longer half-life, a stronger and longer steroidogenic signal via endosomal trafficking, minor FSH-like activity, weak thyrotropic cross-talk at high levels, corpus-luteum maintenance, and androgen-driven testicular descent in pediatric use. The page grades the receptor pharmacology (Grade A) separately from the more speculative downstream applications.
Mechanistically, HCG is a higher-efficacy LHCGR agonist than hLH, with preferential Rab5/early-endosome routing after beta-arrestin-2 recruitment that sustains cAMP and Ca2+. Its beta-CTP extends circulatory half-life and modulates thyrotropic potency. Receptor pharmacology is established in humans; several downstream nodes are mechanistically inferred from in-vitro and pregnancy/trophoblastic data.
This is the core HCG engine layer. HCG is a prescription medication requiring physician supervision; nothing here is a prescription or medical advice. The architecture separates FDA-label and high-evidence reproductive/endocrine dosing (Grade A/B) from off-label community practice (TRT fertility support, PCT; Grade B/D), and adds explicit titration, monitoring, and hard-stop rules. Working unit: International Units (IU) throughout, with reconstitution math in IU/mL.
500-1,000 IU IM 3x/week for hypogonadism, or 5,000-10,000 IU single IM dose for ovulation trigger.2,000-4,000 IU 3x/week for hypogonadism monotherapy; titrate to measured testosterone.1,000 IU/mL (standard). Other options: 5 mL = 2,000 IU/mL; 1 mL = 10,000 IU/mL. Use the calculator below.250-500 IU SC every other day alongside testosterone therapy to maintain intratesticular testosterone and spermatogenesis.500 IU SC every other day is the most-validated co-administration dose; in one cohort it prevented azoospermia in all TRT patients.Wk 1-2: 3,000 IU EOD → Wk 3-4: 2,000 IU EOD → Wk 5-6: 1,000 IU EOD, then transition to a SERM (tamoxifen/clomiphene).500 IU intrauterine within 15 minutes before embryo transfer.| Band | Dose range | Frequency | Indication context | Grade |
|---|---|---|---|---|
| Low | 125-250 IU | EOD (SC) | TRT support; minimal fertility maintenance | D |
| Standard (TRT support) | 500 IU | EOD (SC) | TRT + fertility preservation (most validated) | B/D |
| Standard (hypogonadism) | 500-1,000 IU | 3x/wk (IM/SC) | Hypogonadotropic hypogonadism - initial | A |
| Mid (hypogonadism) | 2,000-3,000 IU | 3x/wk | Moderate; fertility restoration post-TRT | A/B |
| High (hypogonadism) | 4,000 IU | 3x/wk | Severe hypogonadotropic hypogonadism monotherapy | A |
| Ovulation trigger | 5,000-10,000 IU | Single IM | Female ART / ovulation induction | A |
| PCT (speculative) | 1,000-3,000 IU | EOD | Post-AAS HPG-axis recovery | D |
Conversion note: recombinant Ovidrel 250 mcg ~= 6,500 IU biologically and is not interchangeable unit-for-unit with urinary HCG.
| Body weight | Calculated (7.1 IU/kg) | Nearest practical dose | Notes |
|---|---|---|---|
| 55 kg | 391 IU | 375-400 IU EOD | Round to practical syringe unit |
| 65 kg | 462 IU | 450-500 IU EOD | Standard 500 IU acceptable |
| 70 kg | 497 IU | 500 IU EOD | Reference dose |
| 75 kg | 533 IU | 500-550 IU EOD | 500 IU adequate |
| 85 kg | 604 IU | 600 IU EOD | May titrate up |
| 95 kg | 675 IU | 700 IU EOD | Monitor E2 |
| 105 kg | 746 IU | 750-1,000 IU EOD | Reduced bioavailability in obesity |
Basis: 7.1 IU/kg per dose (500 IU EOD at a 70 kg reference). FDA-label hypogonadism doses are fixed, not weight-adjusted; this band is informational for SC self-administration and is Grade D. Obese patients have reduced HCG bioavailability and may need IM over SC or a higher dose.
| Trigger | Action | Rationale |
|---|---|---|
| Total T <300 ng/dL after 4 wk at starting dose | Escalate by 500 IU increment; reassess at 4 wk | Insufficient Leydig-cell stimulation |
| Total T 450-600 ng/dL; symptoms resolved | Maintain current dose | Target therapeutic range achieved |
| Total T >800-1,000 ng/dL | De-escalate by 250-500 IU; recheck 4 wk | Excess androgenization; E2 / gynecomastia risk |
| E2 >50 pg/mL with gynecomastia / mood symptoms | De-escalate; consider AI if persistent | HCG drives T → aromatization at high doses |
| Azoospermia at 3 months despite HCG | Add FSH (75 IU 2-3x/wk) | HCG alone may be insufficient for full spermatogenesis |
| OHSS signs (female): pain, bloating, weight gain >5 lb/wk | HARD STOP - discontinue; contact prescriber; hospitalize if severe | Life-threatening OHSS can progress rapidly |
| Precocious-puberty signs (pediatric) | HARD STOP - discontinue | Androgen-induced premature development |
| Confirmed hormone-sensitive malignancy | ABSOLUTE CONTRAINDICATION | HCG stimulates androgen/estrogen production |
| Marker | Role | Validated for HCG? |
|---|---|---|
| Total testosterone (male) | Primary efficacy marker in hypogonadism | Yes - FDA label |
| LH & FSH | Confirm hypogonadotropic pattern; track axis | Yes - FDA label |
| Semen analysis | Fertility efficacy | Yes - clinical cohort |
| Progesterone (female) | Confirm corpus-luteum function / ovulation | Yes - FDA label |
| Estradiol + follicle count (female) | Follicular development / OHSS risk | Yes - FDA label |
| Estradiol (male) | Monitor aromatization excess | No - not validated for HCG |
| TSH / free T4 | Thyroid stimulation at very high HCG | No - relevant only at >200 IU/mL |
| PSA (males >40) | Prostate safety | No - not validated for HCG |
| Hematocrit | Androgen-driven polycythemia | No - not validated for HCG |
For research/education only. HCG is a prescription drug; use under medical supervision. All math in International Units (IU). Verify product, sterility, and source.
Males: total testosterone, LH, FSH, estradiol, hematocrit, PSA (>40 y), testicular exam, semen analysis if fertility goal. Females: estradiol, progesterone, transvaginal ultrasound (follicle count/size), pregnancy status. Confirm no hormone-sensitive malignancy.
Repeat total testosterone (target 450-600 ng/dL TRT support; 500-1,000 hypogonadism). Check estradiol if symptoms. Apply titration logic - escalate, maintain, or de-escalate.
Estradiol + follicle count every 1-2 days. Withhold the HCG trigger if >20 follicles >12 mm or rapidly rising / very high estradiol - OHSS prevention.
Semen analysis; if azoospermia, add FSH. Continue testosterone and estradiol surveillance; reassess testicular volume.
LH/FSH, hematocrit (>50% - de-escalate), PSA (>40 y). Reassess ongoing need and goals.
OHSS signs, precocious puberty (pediatric), new/active hormone-sensitive malignancy, anaphylaxis/hypersensitivity, thromboembolic event, or pregnancy in a non-fertility context.
HCG's combinations split sharply by evidence: female ART gonadotropin protocols are Grade A and FDA-aligned, male fertility (HCG + FSH) is Grade B, TRT co-administration is Grade B retrospective, and PCT sequencing is Grade D practice-pattern. The engine keeps the strongest agent labelled as the driver and never lets a high-evidence partner inflate a low-evidence use.
Absolute contraindications to HCG use and stacking: active hormone-sensitive malignancy (prostate, breast, endometrial, ovarian); primary gonadal failure (elevated FSH - no functional target tissue); uncontrolled thyroid, adrenal, or pituitary disorders; and known hypersensitivity to gonadotropins. Do not co-administer HCG and a SERM simultaneously - sequence them. In female ART, withhold the HCG trigger when follicle count or estradiol indicate OHSS risk and consider a GnRH-agonist trigger instead. Above all, HCG is a prescription medication: every protocol here assumes physician supervision and appropriate monitoring.
As an established prescription drug, HCG has a defined adverse-event profile: injection-site reactions, and - most seriously - ovarian hyperstimulation syndrome (OHSS) in women, which can be life-threatening. In men the dominant issues are excess androgenization and aromatization (gynecomastia, mood, hematocrit). The hard boundaries are hormone-sensitive cancers, primary gonadal failure, uncontrolled endocrinopathies, and gonadotropin hypersensitivity.
| Condition | Concern | Severity |
|---|---|---|
| Hormone-sensitive malignancy (prostate, breast, uterine, ovarian) | Androgens/estrogens stimulate tumor growth | Absolute |
| Primary gonadal failure (high FSH) | No functional target tissue; ineffective and misleading | Absolute |
| Uncontrolled thyroid disorder | Weak TSH-agonist activity can worsen imbalance | Absolute |
| Uncontrolled adrenal or pituitary disorder | Confounds hormonal evaluation and management | Absolute |
| Gonadotropin hypersensitivity | Anaphylaxis risk | Absolute |
| Severe thrombophilia / prior VTE | OHSS + HCG synergistically raise thrombosis risk | Strong relative |
| Severe obesity (BMI >35) | Reduced bioavailability; modified OHSS risk - adjust dose/route | Relative |
| Renal/cardiac disease, epilepsy, migraine, asthma | Androgen-induced fluid retention may worsen - monitor | Relative |
| Pediatric treatment + precocious puberty | Discontinue if signs emerge | Conditional stop |
| Concurrent active AAS use (PCT context) | Cannot overcome supraphysiologic suppression; prolongs recovery | Relative (D) |
| Competitive athlete / WADA testing pool | Banned at all times under S2.2.1 | Absolute |
Baseline → 4-8 wk → q3 months. Target 450-600 ng/dL (TRT support) or 500-1,000 (hypogonadism Tx). Drives titration decisions.
Baseline; q6 months. Low baseline confirms hypogonadotropic pattern; track axis behavior on therapy.
Daily / alternate days during stimulation. Estradiol >3,000 pg/mL or >20 follicles → withhold the HCG trigger (OHSS prevention).
Daily during stimulation and ~2 weeks post-HCG. Gain >5 lb/week → OHSS alert and clinician contact.
q6 months. Hematocrit >50% → de-escalate; rising PSA (>40 y) → prostate evaluation. Not HCG-specific endpoints.
TSH / free T4 only if clinical hyperthyroid signs - relevant mainly at supratherapeutic HCG levels, not standard dosing.
Unlike most peptides in this atlas, HCG rests on a deep human evidence base: pharmacokinetic RCTs, ART meta-analyses, and FDA-label trials. The honest picture is split - Grade A for reproductive uses and route equivalence, Grade B for male fertility/TRT support, Grade D for PCT, and a clear, repeatedly demonstrated negative result for weight loss.
A randomized three-way crossover in pituitary-suppressed volunteers (n=18) found SC and IM HCG bioequivalent in extent of absorption (AUC), with elimination half-life ~32-33 h and Tmax ~20 h. The basis for using SC as a practical self-administration route.
Meta-analysis of 15 RCTs (n=2,763): 500 IU intrauterine HCG within 15 min before transfer improved live-birth, ongoing/clinical pregnancy, and implantation rates; 100-200 IU showed no significant benefit, only 500 IU did.
The FDA label defines three indications (ovulation induction, male hypogonadotropic hypogonadism, prepubertal cryptorchidism), the dosing regimens, the OHSS and contraindication warnings, and the explicit statement that HCG is not effective for weight loss.
A retrospective cohort reported that 500 IU HCG every other day maintained normal semen parameters during testosterone replacement and supported intratesticular-testosterone preservation across a dose ladder (125/250/500 IU EOD). Grade B - no RCT.
A criteria-based meta-analysis found no scientific evidence that HCG aids weight loss, fat redistribution, hunger, or well-being beyond placebo. A critical assessment of the Simeons method reached the same conclusion. A definitive, repeatedly replicated negative.
Human mechanistic work shows hCG drives higher beta-arrestin-2 recruitment and Rab5 early-endosome routing (prolonged steroidogenic signaling), whereas LH favors Rab11 recycling and a proliferative ERK profile. In mouse Leydig cells, the two ligands signal differently early but yield equal testosterone.
HCG's evidence is high for its approved reproductive/endocrine indications (Grade A for ovulation induction/ART and route equivalence; Grade B for male hypogonadism and fertility restoration) and rests on decades of randomized human data. Intrauterine HCG before embryo transfer is supported by a Grade A meta-analysis of 15 RCTs. What is weaker or absent: no RCT supports TRT fertility-preservation co-administration (Grade B retrospective at best) or PCT protocols (Grade D); long-term safety beyond reproductive endpoints is sparse; and weight-loss use is definitively unsupported - HCG is no better than placebo. This page therefore presents the off-label dosing engine as a supervised hypothesis layer, not a guideline.
| Study | Design | n | Route / dose | Outcome | Grade |
|---|---|---|---|---|---|
| Matorras 1998 | RCT crossover (PK) | 18 | SC vs IM; 5-10k IU | IM/SC bioequivalent; t½ 32-33 h | A |
| Kovacs 2003 | Controlled PK | - | SC vs IM; 10k IU | IM > SC in obese; obesity lowers both | B |
| Kyrou 2019 | Meta-analysis (15 RCTs) | 2,763 | Intrauterine 500 IU | LBR 44.89% vs 29.76% | A |
| TRT + HCG cohort | Retrospective | 26 | SC 500 IU EOD + TRT | No azoospermia; 9 pregnancies | B |
| Natural-cycle FET luteal HCG | RCT double-blind | - | SC luteal support | No improvement in ongoing pregnancy | A |
| Simeons-protocol meta | Criteria-based meta | multi | IM (weight loss) | No benefit vs placebo | A (neg) |
| FRTL-5 thyroid | Cell study | - | in vitro | hCG activates TSHR; cAMP, growth | C |
HCG is the direct, long-acting LH-receptor agonist. Its neighbors act at different nodes - upstream (kisspeptin, GnRH), at the pituitary (clomiphene/SERMs), or as a shorter-acting recombinant LH - which clarifies when HCG is the right tool and when a more physiological option fits better.
| Feature | HCG | Kisspeptin-10 | Clomiphene | rLH (Luveris) |
|---|---|---|---|---|
| Mechanism class | LHCGR direct agonist | KISS1R agonist → GnRH → LH/FSH | SERM (blocks pituitary ER) | Recombinant LH (LHCGR agonist) |
| Primary use | Testosterone / ovulation trigger / cryptorchidism | Investigational fertility (preserves pulsatility) | Ovulation induction; off-label male | Ovulation support with FSH |
| Evidence tier | Grade A (3 FDA uses, decades of RCTs) | Grade B/P (investigational) | Grade A (female); off-label male | Grade A (FDA-approved) |
| Half-life | ~32-33 h | ~28 min (IV, very short) | 5-7 days (oral) | ~10 h (SC) |
| Route | IM, SC, intrauterine | IV, SC (investigational) | Oral | SC |
| Regulatory / WADA | FDA Rx; WADA S2.2.1 banned | Investigational; not yet WADA-listed | FDA-approved; WADA S4.2 banned (males) | FDA-approved; WADA-restricted |
| Key advantage | Direct, potent, long-lasting; preserves testicular function on TRT | Physiological; preserves GnRH/LH pulse | Oral; preserves endogenous axis | Physiological LH; shorter t½ less desensitization |
| Key limitation | OHSS; LHCGR desensitization; banned in sport; injection | Short t½; expensive; not approved | Needs intact HPG axis; ineffective in primary failure | Frequent dosing; expensive; injection only |