Peptide profile · Hormone Support
Human Chorionic Gonadotropin (HCG)
A powerful hormone that mimics luteinizing hormone (LH) to stimulate your body's natural testosterone production while keeping your fertility intact—like having your cake and eating it too for men on hormone therapy.
Written by Michael Carroll — Owner, Director of Research · Reviewed by the Peptide Initiative Research Team
Typical dose
500-1,500 IU
Half-life
24-36 hours
Bioavailability
High when injected subcutaneously or intramuscularly
Molecular weight
36,700 g/mol (approximately)
Evidence level
Strong human trials
01 · Compound profile
Scientific & efficacy data
Molecular formula
C1105H1770N318O336S26 (approximate)
Primary benefits
Gold standard for maintaining sperm production during TRT—research shows ~80% success rate in preserving or restoring spermatogenesis
Highly effective at preventing and reversing testicular atrophy caused by external testosterone or steroid use
Supports natural testosterone production and helps maintain healthy intratesticular hormone levels alongside TRT
Charité University Hospital, Berlin
Amino acid sequence
Heterodimeric glycoprotein: alpha subunit (92 amino acids) common to LH, FSH, TSH; beta subunit (145 amino acids) unique to HCG02 · Dosing
How much do I take?
500-1,500 IU · 2-3 times per week
Subcutaneous: A small injection into the fatty layer just under the skin — the same way insulin is given.
Bioavailability High — most of the dose reaches your bloodstream, just more gradually than an IV.
Best time to take
Most men inject HCG on set days—for example, Monday and Thursday, or Sunday and Wednesday. Time of day doesn't matter much, but consistency helps you remember. Some prefer morning injections.
With food?
HCG can be taken regardless of food timing. Absorption is not affected by meals since it's injected, not taken orally.
If stacking
When using with testosterone, inject HCG on the same days or alternate days—both approaches work. If using an aromatase inhibitor, take it as prescribed to manage any estrogen increase from HCG.
＋ Increase if
- +Testicular volume continues to decrease despite current dose
- +Sperm count remains suppressed when fertility is the goal
- +Your doctor determines testosterone response is inadequate
- +You're transitioning to a fertility-focused protocol
－ Decrease if
- −Estrogen levels rise too high (confirmed by blood work)
- −You experience significant water retention or bloating
- −Gynecomastia symptoms develop (tender or swelling breast tissue)
- −Mood swings or irritability become problematic
✓ Signs of right dose
- ✓Testicles maintain normal size and firmness
- ✓Hormone levels (testosterone, estrogen, LH) are in healthy ranges
- ✓Sperm production maintained or improved (if monitored)
- ✓No significant side effects like gynecomastia or water retention
Dosing Calculator
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03 · Suitability
Is this right for me?
Best for fertility preservation during trt & maintaining testicular size and function
Best for
Fertility Preservation During TRT
If you're on testosterone therapy but want to keep your swimmers swimming, HCG is your best friend. It keeps your testes active and producing sperm even when external testosterone would normally shut that down. Research shows it can maintain or restore spermatogenesis in about 80% of men.
Preventing Testicular Atrophy
Nobody wants their boys to shrink. When you take external testosterone, your brain stops signaling your testes to work—and they get smaller from disuse. HCG mimics the signal (LH) that keeps them active, maintaining their size and function.
Hypogonadotropic Hypogonadism
If your pituitary gland isn't sending the right signals to your testes (low LH), HCG can step in and do the job. It's been used for decades to treat this condition, helping men achieve normal testosterone levels and fertility.
Post-Cycle Therapy (PCT)
After using anabolic steroids, your natural hormone production is suppressed. HCG can help jumpstart your testes back into action, speeding up the recovery of your natural testosterone production. It's often used as part of a comprehensive PCT protocol.
Consider alternatives if
Do not use if
Use with caution if
Not sure?
Compare Human Chorionic Gonadotropin (HCG) with similar peptides to find the best fit for your goals.
04 · Administration
How do I use it?
Subcutaneous injection · Intramuscular injection
Reconstitution — what you need
Example
If you have a 5,000 IU vial and add 2.5mL of BAC water, you get a concentration of 2,000 IU/mL. So every 0.25mL (25 units on an insulin syringe) equals 500 IU of HCG.
For a 500 IU dose at 2,000 IU/mL concentration: draw 0.25mL (25 units on a standard insulin syringe). For 1,000 IU: draw 0.5mL (50 units).
Route
Subcutaneous injection (just under the skin) or intramuscular injection—subcutaneous is easier for self-administration and equally effective
Best sites
Technique
- 01Wash your hands thoroughly with soap and water
- 02Clean the injection site with an alcohol swab and let it air dry
- 03For subcutaneous: pinch about an inch of skin to create a fold
- 04Insert the needle at a 45-90 degree angle (45 if you're lean, 90 if you have more tissue)
- 05Push the plunger slowly and steadily over 5-10 seconds
- 06Wait a few seconds before removing the needle
- 07Apply light pressure with a clean swab if needed—don't rub
Storage · before reconstitution
Keep your HCG powder in the refrigerator (36-46°F / 2-8°C). While some products claim room temperature stability, refrigeration extends shelf life. Store in the original sealed vial away from light. Properly stored powder remains stable for 1-2 years.
Storage · after reconstitution
Once mixed with bacteriostatic water, refrigerate at 36-46°F (2-8°C). Never freeze the reconstituted solution—freezing damages the protein structure and destroys the hormone. Keep away from light. Use within 30-60 days depending on your provider's guidance.
Signs of degradation
Sample daily schedule
05 · Safety
Is it safe?
3 common side effects · 3 serious
HCG has been used medically for over 80 years with a well-established safety profile. When used appropriately for male hypogonadism or fertility preservation, side effects are generally mild and manageable. The most common issues relate to elevated estrogen from increased testosterone aromatization, which can be managed with aromatase inhibitors if needed. Serious side effects are rare when HCG is used under medical supervision.
HCG is FDA-approved for specific indications including hypogonadotropic hypogonadism in males. There's substantial clinical evidence from decades of use in fertility medicine and more recent research on its role in TRT protocols. Large real-world studies have confirmed its safety and effectiveness when properly monitored.
Common side effects · experienced by some users
Less common
These typically resolve with continued use or dose adjustment.
Stop and seek help if
- ×Signs of allergic reaction—rash, hives, swelling, difficulty breathing (stop immediately, seek emergency care)
- ×Significant gynecomastia development that doesn't respond to estrogen management
- ×Blood clot symptoms—sudden leg pain/swelling, chest pain, shortness of breath (stop immediately, seek emergency care)
- ×Your fertility or TRT goals have been achieved and your doctor recommends discontinuation
- ×Unacceptable side effects that don't improve with dose adjustments
- ×Development of hormone-sensitive conditions
HCG is a prescription medication and should only be used under medical supervision. Never start, stop, or adjust your dosing without consulting your healthcare provider. This information is for educational purposes only—not medical advice.
With other peptides
- ✓Gonadorelin — Both stimulate the reproductive axis through different mechanisms. Can be used together in some protocols but monitor hormone levels carefully.
- ✓Kisspeptin — Experimental combination—both affect gonadotropin release. Limited data on concurrent use.
- ✓BPC-157 — No known interaction. Different mechanisms of action.
With medications
- ✓Testosterone (TRT) — Commonly used together. HCG helps maintain testicular function during TRT. This is a standard protocol.
- ✓Clomiphene citrate — Often combined for fertility protocols or PCT. Both stimulate testosterone through different pathways.
- ✓Aromatase inhibitors (Anastrozole) — May be needed to control estrogen that rises with HCG use. Monitor levels and dose appropriately.
- ✓Blood thinners (Warfarin, etc.) — May increase bruising at injection sites. Monitor INR closely as hormone changes can affect clotting.
- ✓Thyroid medications — HCG has weak TSH-like activity. Monitor thyroid function if on thyroid medication.
With supplements
- ✓DHEA — Both affect hormone levels. Use together cautiously and monitor hormone panels.
- ✓Zinc supports testosterone production and is safe to take with HCG.
- ✓Vitamin D — Important for hormone health. Safe and potentially complementary.
- ✓DIM (Diindolylmethane) — May help with estrogen metabolism. Can be used alongside HCG.
06 · Effectiveness
How do I know it's working?
Strong human trials · first signs week 1-2
Evidence level
Strong human trials
(Phase 3 or FDA approved)
How it works
HCG is a hormone that tricks your body into thinking it's receiving the signal to make testosterone. Normally, your brain releases LH (luteinizing hormone) which tells your testes to produce testosterone and keep sperm production running. When you take external testosterone, your brain stops sending that LH signal because it thinks there's enough testosterone already. HCG steps in and mimics LH, binding to the same receptors on your testes and keeping them active—producing testosterone and maintaining sperm production even when you're on TRT.
Human chorionic gonadotropin is a heterodimeric glycoprotein composed of an alpha subunit (shared with LH, FSH, and TSH) and a unique beta subunit that confers biological specificity. HCG binds to the LH/CG receptor (LHCGR) on testicular Leydig cells with high affinity, triggering a G-protein coupled signaling cascade that activates adenylyl cyclase, increases intracellular cAMP, and stimulates steroidogenesis through upregulation of StAR (steroidogenic acute regulatory protein) and steroidogenic enzymes. This results in testosterone synthesis from cholesterol via the classic steroidogenic pathway. The longer half-life of HCG (24-36 hours) compared to LH (20 minutes) is due to its higher sialic acid content, which reduces renal clearance. Intratesticular testosterone levels maintained by HCG are essential for spermatogenesis, as Sertoli cells require paracrine testosterone signaling for proper germ cell development. HCG's beta-subunit contains the carboxy-terminal peptide (CTP) extension that increases molecular stability and receptor residence time.
What to expect
Week 1-2
What you might notice
- •Injection site reactions as your body gets used to the medication
- •Possible mild headaches or fatigue during adjustment
- •Some men notice improved mood or libido relatively quickly
- •Your body is beginning to respond to the LH-like stimulation
What's normal
- •Not feeling dramatic changes yet—HCG works gradually
- •Minor injection site redness or soreness that fades
- •Some water retention or mild bloating
What's next
- →Continue your prescribed protocol consistently
- →Track how you feel in a simple log
- →Side effects typically improve after the first couple weeks
Week 3-6
What you might notice
- •Testicles maintaining size or returning to fuller size
- •Stable testosterone levels when combined with TRT
- •Improved energy, libido, and overall well-being
- •Body adjusting to the hormonal changes
What's normal
- •Settling into the routine with fewer initial side effects
- •Noticeable testicular fullness compared to before HCG
- •Stable mood and energy levels
What's next
- →Blood work at 4-6 weeks to check testosterone, estrogen, and other markers
- →Dose adjustments may be made based on lab results
- →Continue monitoring for any gynecomastia signs
Week 8-12 and beyond
What you might notice
- •Sustained testicular size and function
- •For fertility goals: sperm count may be returning or maintained
- •Stable hormonal balance with good quality of life
- •Long-term benefits becoming apparent
What's normal
- •HCG becomes a routine part of your protocol
- •Consistent results with minimal side effects
- •Fertility preserved or improving (if that's your goal)
What's next
- →Regular monitoring every 3-6 months (blood work)
- →Semen analysis if fertility is the goal
- →Ongoing protocol adjustments as needed based on labs and symptoms
Signs it's working · Testicular Health Indicators
- ✓Testicles maintain normal size and firmness (no shrinkage)
- ✓Testicles feel full rather than soft or atrophied
- ✓No continued decrease in testicular volume while on TRT
Signs it's working · Hormonal Balance
- ✓Blood work shows maintained or improved testosterone levels
- ✓Estrogen levels are within healthy range (managed if elevated)
- ✓LH and FSH levels appropriate for your protocol
- ✓Overall hormone panel looks balanced
Signs it's working · Fertility Markers (if applicable)
- ✓Semen analysis shows sperm present and improving counts
- ✓Sperm motility and morphology within acceptable ranges
- ✓FSH levels responding appropriately (in combination protocols)
Signs it's working · Quality of Life
- ✓Maintained or improved libido and sexual function
- ✓Stable energy levels throughout the day
- ✓Good mood and mental clarity
- ✓No significant unwanted side effects
Not seeing results? Common reasons
- •Dose too low—some men need higher doses to maintain testicular function, especially if already significantly suppressed
- •Poor quality HCG from unreliable source—always use pharmaceutical-grade product from licensed pharmacies
- •Improper storage degraded the hormone—HCG is a protein and degrades if not refrigerated or if frozen after reconstitution
- •Not enough time—testicular recovery and spermatogenesis take months, not weeks
- •Estrogen rising unchecked—high estrogen can counteract some benefits; may need an aromatase inhibitor
- •Underlying primary hypogonadism—if testes are damaged, they may not respond to HCG (it requires functioning Leydig cells)
Key research
07 · Clinical trials
Tested in people
273 registered studies, 26 still enrolling.
273
registered studies
26
recruiting now
108
phase 3 or 4
63
with published results
By phase
A trial spanning two phases is counted in both, so these can sum above the total. Observational studies carry no phase.
What kind of research
About 38,169 people took part in the studies that actually administered Human Chorionic Gonadotropin (HCG). Observational studies analyse the records of people already taking it — nobody was given anything for the study, so they are counted separately and cannot show cause and effect.
Most recent
hCG Treatment for Rehabilitation From a TBI
VA Office of Research and Development
Purpose to Evaluate the Effectiveness of the Superovulation Stimulation Protocol Using Human Chorionic Gonadotropin (hCG) by Demonstrating Its Equivalence to Standard Controlled Ovarian Stimulation Protocols in Terms of Oocytes Retrieved, Blastulation While Maintaining an Economic Advantage
LTD "EKODNIPRO", Medical centre Medical Plaza Dnipro
Gonadotropin Therapy in Idiopathic Hypogonadal Non-Obstructive
Indira IVF Hospital Pvt Ltd
Sources: ClinicalTrials.gov, the EU Clinical Trials Information System and ISRCTN, deduplicated so a study registered twice is counted once. A study is counted when Human Chorionic Gonadotropin (HCG) is named as an intervention; studies that only mention it in passing are not.
08 · Questions
Frequently asked
Why would I need HCG if I'm already taking testosterone?+
When you take external testosterone, your brain thinks you have enough and stops telling your testes to work. Over time, your testes can shrink and stop making sperm. HCG keeps your testes active and functioning, preventing shrinkage and maintaining fertility—a major advantage if you ever want to have kids or simply want to keep things working down there.
Does HCG work for weight loss?+
No. The 'HCG diet' combined very low calories (500 per day) with HCG injections, but multiple studies have shown the weight loss comes from the extreme calorie restriction, not the HCG. The FDA has called HCG weight loss products fraudulent. Don't use HCG for weight loss—it doesn't work and the severe calorie restriction is unhealthy.
How long until HCG starts working?+
You may notice some effects like testicular fullness within a few weeks. However, for fertility goals, sperm production takes about 74 days (the full spermatogenesis cycle), so meaningful improvements in sperm counts typically take 3-6 months of consistent use. For maintaining testicular size, you'll often notice benefits within the first month.
Can HCG cause gynecomastia (man boobs)?+
Yes, it can. HCG increases testosterone production in your testes, and some of that testosterone converts to estrogen through an enzyme called aromatase. If estrogen rises too high, it can cause breast tissue growth. This is manageable with proper monitoring and, if needed, an aromatase inhibitor. Regular blood work helps catch rising estrogen early.
Is HCG the same as steroids?+
No. HCG is a hormone that stimulates your own testes to produce testosterone—it's not testosterone itself. Think of it as a signal that tells your body to make its own hormones, rather than providing external hormones directly. It's often used alongside testosterone therapy to maintain natural testicular function.
Can I use HCG on its own without testosterone?+
Yes, some men use HCG monotherapy to boost their natural testosterone production without taking external testosterone. This approach maintains fertility and testicular function while increasing testosterone levels. However, the testosterone boost from HCG alone is typically more modest than from TRT, so it depends on your specific situation and goals.
How often do I need blood work while on HCG?+
Most doctors recommend blood work every 4-6 weeks when starting HCG, then every 3-6 months once you're stable. Key markers to monitor include testosterone (total and free), estrogen (estradiol), hematocrit, and PSA. If fertility is your goal, periodic semen analyses are also important.
Will my testicles go back to normal size with HCG?+
In most cases, yes. If your testicles have shrunk from TRT or steroid use, HCG can restore their size over time. How much they recover depends on how long they were suppressed and individual factors. Most men see significant improvement within a few months of consistent HCG use.
09 · Further reading