hCG
Also known as: Human Chorionic Gonadotropin, Pregnyl, Novarel, Ovidrel
Human Chorionic Gonadotropin, a hormone that mimics LH to stimulate testosterone production. Commonly used for fertility, TRT support, and post-cycle therapy.
Half-Life
24-36 hours
Typical Dose
250-500 IU
Frequency
2-3x weekly
Routes
Subcutaneous
Overview
Human Chorionic Gonadotropin (hCG) is a naturally occurring hormone produced during pregnancy. In males, hCG mimics Luteinizing Hormone (LH), stimulating the Leydig cells in the testes to produce testosterone. This makes it invaluable for maintaining testicular function during testosterone replacement therapy (TRT) and for fertility preservation.
hCG has been FDA-approved for decades for both fertility treatment and certain hormonal conditions, making it one of the most well-established peptide hormones in clinical use.
Key Characteristics
- Origin: Natural hormone (pregnancy), also produced via recombinant technology
- Classification: Gonadotropin hormone
- FDA Status: Approved for fertility and specific hormonal conditions
- Unique Feature: Directly stimulates endogenous testosterone production
- Primary Use: TRT support, fertility, post-cycle therapy
Why hCG Matters for TRT
When on TRT, the body's natural LH production shuts down. Without LH:
- Testes shrink (testicular atrophy)
- Natural testosterone production ceases
- Fertility is impaired
- Pregnenolone/DHEA production decreases
hCG prevents these issues by acting as an LH substitute.
Mechanism
Primary Mechanisms
1. LH Receptor Activation
hCG's primary action:
- Binds to LH/hCG receptors on Leydig cells
- Activates cAMP signaling cascade
- Stimulates testosterone synthesis
- Maintains intratesticular testosterone (ITT)
2. Testicular Preservation
During TRT:
- Prevents testicular atrophy
- Maintains sperm production
- Preserves fertility potential
- Supports testicular health
3. Upstream Hormone Support
Beyond testosterone:
- Maintains pregnenolone production
- Supports DHEA synthesis
- Preserves neurosteroid production
- May improve well-being
4. Ovarian Stimulation (Women)
In females:
- Triggers ovulation
- Used in fertility treatments
- Supports corpus luteum
- Maintains early pregnancy
Research
Research Note: hCG has extensive clinical research and decades of FDA-approved use. It is one of the most well-studied hormones in medicine.
TRT Combination Studies
Testicular Function Preservation
Research demonstrates:
- Maintains testicular volume during TRT
- Preserves sperm production in most men
- Intratesticular testosterone remains adequate
- Prevents the "shutdown" associated with TRT alone
Fertility Research
Male Fertility
Studies show:
- Can restore spermatogenesis during/after TRT
- Effective for hypogonadotropic hypogonadism
- Works synergistically with FSH (hMG)
- Higher success rates when started early
Female Fertility
Well-established for:
- Ovulation induction
- IVF trigger shots
- Luteal phase support
- Polycystic ovary syndrome
Post-Cycle Therapy
Steroid Discontinuation
Research indicates:
- Accelerates testosterone recovery
- Reduces hypogonadal symptoms
- May shorten recovery time
- Best combined with SERMs
Dosing
Disclaimer: hCG is a prescription medication. Dosing should be determined by a healthcare provider based on individual needs and lab work.
Research Protocols
| Protocol | Dose | Frequency | Duration |
|---|---|---|---|
| TRT Support | 250-500 IU | 2-3x weekly | Ongoing with TRT |
| Fertility Preservation | 500-1000 IU | 2-3x weekly | Ongoing |
| Monotherapy | 1000-2000 IU | 2-3x weekly | As prescribed |
| PCT | 500-1000 IU | Every other day | 2-4 weeks |
Administration Notes
Timing
- Can be taken any time of day
- Consistent timing preferred
- Often administered on non-TRT injection days
- Some prefer same-day as TRT
Injection Technique
- Subcutaneous preferred (less painful)
- Intramuscular also effective
- Rotate injection sites
- Insulin syringes work well for SubQ
Reconstitution
- Use bacteriostatic water
- Typical: 5000 IU vial + 5ml water = 1000 IU/ml
- Refrigerate after reconstitution
- Use within 30-60 days
Finding the Right Dose
Signs of adequate dose:
- Maintained testicular size
- Preserved fertility (if desired)
- Good energy and libido
- Estrogen not excessively elevated
Signs dose may need adjustment:
- Testicular shrinkage
- Elevated estrogen symptoms
- Fatigue or mood changes
- Lab work indicating issues
Pharmacokinetics
Absorption
- Subcutaneous: Slow, sustained absorption
- Intramuscular: Moderate absorption
- Peak levels: 6-24 hours post-injection
Distribution
- Distributes to reproductive tissues
- Crosses into testes
- Limited CNS penetration
Metabolism
- Primarily hepatic metabolism
- Some renal clearance
- Metabolites inactive
Elimination
- Half-life: 24-36 hours
- Allows 2-3x weekly dosing
- No significant accumulation
- Steady state: ~1 week
Synergy & Stacking
Common Combinations
hCG + TRT
Standard protocol:
- TRT provides exogenous testosterone
- hCG maintains testicular function
- Prevents atrophy and fertility loss
- Most common combination
hCG + hMG (or FSH)
For fertility:
- hCG provides LH activity (testosterone)
- hMG/FSH provides FSH activity (sperm)
- Synergistic for spermatogenesis
- Used when hCG alone insufficient
hCG + AI (Aromatase Inhibitor)
If estrogen elevated:
- hCG can raise estrogen
- Low-dose AI may be needed
- Monitor estrogen levels
- Adjust based on symptoms/labs
Timing Considerations
- Can inject same day as TRT or alternate days
- Some protocols spread doses throughout week
- Consistency more important than specific timing
- Individualize based on response
Safety
Known Side Effects
Common (dose-dependent)
- Elevated estrogen (gynecomastia risk)
- Water retention
- Mood changes
- Acne
Less Common
- Headache
- Irritability
- Injection site reactions
- Fatigue
With Excessive Use
- Desensitization of Leydig cells (rare)
- Persistent estrogen elevation
- Testicular desensitization
Contraindications
Avoid if:
- Prostate cancer
- Hormone-sensitive cancers
- Precocious puberty (in boys)
- Hypersensitivity to hCG
Use with caution if:
- History of blood clots
- Heart disease
- Migraine disorders
- Asthma
Estrogen Management: hCG can significantly raise estrogen levels. Monitor for symptoms of elevated estrogen and check labs regularly. Some men may need an aromatase inhibitor.
Drug Interactions
- May interact with other hormonal therapies
- Can affect thyroid function tests
- Coordinate with prescribing physician
- Monitor when combining with other fertility drugs
Monitoring
Baseline Assessments
- Total and free testosterone
- Estradiol (E2)
- LH and FSH
- Complete blood count
- Prostate-specific antigen (if indicated)
During Treatment
- Testosterone levels (4-6 weeks after starting)
- Estradiol monitoring
- Testicular size assessment
- Semen analysis (if fertility important)
Signs of Response
- Stable testicular size
- Testosterone levels appropriate
- Estrogen not excessively elevated
- Maintained fertility markers
Regulatory
Current Status
| Region | Status | |--------|--------| | United States | FDA-approved prescription medication | | WADA | Strictly Prohibited (S2 category) | | Availability | Prescription required; brand and generic available | | Insurance | Often covered for approved indications |
Legal Considerations
- Schedule III in some jurisdictions
- Requires prescription in most countries
- Athletes: Strictly banned
- Legitimate medical uses are protected
Clinical Outlook
hCG remains the gold standard for:
- Testicular function preservation on TRT
- Male fertility preservation
- Ovulation induction in women
- Hypogonadotropic hypogonadism treatment
Its long safety record and FDA approval make it a cornerstone of hormone optimization protocols.