HCG and Fertility on TRT: What Men Need to Know

The Fertility Problem With TRT

When you start testosterone replacement therapy, exogenous testosterone shuts down your body's own testosterone production through negative feedback.

Here's the chain:

You take testosterone (injection, gel, or patch)
Your pituitary detects high testosterone and responds by reducing LH (luteinizing hormone) and FSH (follicle-stimulating hormone) secretion
LH drop: Without LH stimulation, your testes stop producing their own testosterone
FSH drop: Without FSH stimulation, sperm production (spermatogenesis) stops
Result: Azoospermia (no sperm in ejaculate) within 4–8 weeks

Additionally:

Testicular atrophy: Your testes shrink from disuse (no LH stimulation)
Infertility: You're unable to father biological children while on TRT

This is fully reversible if you stop TRT (sperm recovery takes 3–6 months, testicular recovery takes 3–12 months). But if you're on TRT long-term and want to have biological children, you need a solution.

That solution is HCG.

What Is HCG and How Does It Work?

HCG (human chorionic gonadotropin) is a hormone normally produced during pregnancy. It acts like LH (luteinizing hormone) in men.

How it works:

HCG binds to the same receptors as LH on the Leydig cells of the testes. When you take HCG:

Testicular testosterone production continues: Your testes keep producing testosterone despite exogenous testosterone being present
Spermatogenesis is maintained: FSH levels (which drive sperm production) don't drop as dramatically when LH is stimulated by HCG
Testicular size and function preserved: The testes don't atrophy because they're still receiving stimulation

On TRT + HCG:

You maintain your own testicular testosterone production
Your testes don't shrink
Sperm production is largely preserved
Fertility is maintained

Who Needs HCG on TRT?

You should consider HCG if:

You want to have biological children (future or present): Fertility preservation is the primary indication.
You want to preserve testicular size and function: Even if you're not planning kids, some men prefer to maintain normal testicular appearance and function.
You're on TRT long-term: If TRT is permanent (not trial), HCG makes sense.

You might skip HCG if:

You're older and don't want more children: No biological children planned.
You're trialling TRT short-term: 3–6 month trial to see how you feel.
Cost is prohibitive: HCG adds £40–100/month to your TRT cost.

Critical point: If you're of reproductive age and might ever want biological children, HCG should be part of your protocol from the start. Recovering fertility after years on TRT without HCG is possible but takes many months (6–12+).

HCG Dosing and Protocols

Standard Dosing

Typical starting dose: 500–1000 IU, 2–3 times per week.

Example protocols:

Option 1: 500 IU, three times weekly (Monday/Wednesday/Friday)
Option 2: 1000 IU, twice weekly (Monday/Thursday)
Option 3: 750 IU, three times weekly (for a dose in between)

All three achieve similar effects. Choice is usually based on convenience or doctor preference.

Adjusting Dose

HCG is titrated based on:

Testicular response: Testes should remain normal size (not atrophied)
Semen analysis: Sperm count should remain measurable (though may not be "normal")
Oestradiol levels: HCG can increase oestradiol (the testes produce some oestradiol under HCG stimulation), so monitoring is needed

If testicular atrophy is still occurring, the dose is too low — increase it.

If oestradiol is very high (> 60 pg/mL), dose might be too high — consider reducing it slightly or adding aromatase inhibitor.

How to Administer HCG

HCG comes as a powder that you reconstitute with saline solution provided.

Reconstitution

HCG vial: Contains 5000 IU powder (typically)
Saline vial: 1 ml preservative-free saline (or sometimes 2 ml)
Mix: Inject the saline into the HCG vial, gently swirling to dissolve (don't shake)
Calculation: If 5000 IU in 1 ml, then each 0.1 ml = 500 IU

Injection

Route: Subcutaneous (sub-Q) injection, same as HCG is almost always given sub-Q
Sites: Abdomen or thigh (rotate sites)
Needle: 27–29G, 0.5 inch (small needle, subcutaneous)
Frequency: 2–3 times weekly (Monday/Wednesday/Friday is common)

HCG is relatively painless via sub-Q injection.

Storage

Once reconstituted, HCG remains stable for 30–60 days if refrigerated. Most men reconstitute one vial and use it over 4–6 weeks before reconstituting a fresh vial.

Timeline: When HCG Works

Week 1–2

Testicular LH stimulation begins. The testes start responding to HCG and increase testosterone production.

Week 4–6

Testicular size is preserved. Spermatogenesis is being maintained. Blood tests should show testicular response (elevated LH-stimulated testosterone production if measured).

Week 8–12

Full effects are evident. Sperm production is maintained (though may be lower than pre-TRT baseline — that's normal). Testicular volume is normal.

Ongoing

Continued HCG maintains testicular function. Semen analysis (if done) should show measurable sperm, typically ranging from oligozoospermia (low sperm count) to normozoospermia (normal count), depending on individual factors.

Fertility Testing on TRT + HCG

If you want confirmation that you're maintaining fertility on TRT + HCG, semen analysis is the definitive test.

What to expect:

Pre-TRT baseline: Normal semen analysis (assuming normal fertility before)
On TRT without HCG: Azoospermia (no sperm) by week 8–12
On TRT + HCG: Oligozoospermia (reduced sperm count) to normozoospermia (normal count). Sperm count is usually lower than baseline, but typically fertile-range

A semen analysis costs £100–200 (private). If you're planning to father children, getting one at baseline, then again after 3 months on TRT + HCG, gives you reassurance.

Cost and Availability of HCG in the UK

NHS

HCG is available on NHS prescription but typically only for fertility-related indications. Obtaining it on NHS for TRT-related fertility preservation can be difficult and requires documentation of fertility intent.

Private

Private clinics often include HCG in their standard TRT protocol or offer it as add-on. Cost typically £40–100/month depending on dose.

Self-sourcing

Some men source HCG through online pharmacies (not recommended for quality/safety reasons).

Practical: Most men's health clinics in the UK now routinely include HCG as part of TRT protocols. It's becoming standard rather than optional. If your clinic isn't offering it, ask why.

Alternatives: Restarting Testosterone After TRT

If you come off TRT and want to restart your own testosterone production and fertility, clomiphene (and enclomiphene) are alternatives.

Clomiphene (Clomid)

Clomiphene is a selective oestrogen receptor modulator (SERM) that blocks oestrogen feedback at the pituitary, allowing LH and FSH to recover.

Protocol: 25–50 mg daily.

Effects:

LH rises
FSH rises
Endogenous testosterone production restarts
Spermatogenesis recovers over weeks to months

Advantages:

Oral (no injections)
Relatively inexpensive
Restarts your own testosterone production

Disadvantages:

Doesn't work as monotherapy while on TRT (can't take clomiphene while taking TRT — the exogenous testosterone overrides clomiphene's effects)
Less reliable than HCG at maintaining fertility during TRT
Can increase oestradiol (some men get mood symptoms, gynecomastia)

When to use: Clomiphene is useful if you're planning to come off TRT and want to restart your own testosterone quickly (particularly relevant if you're trialling TRT and want to stop).

Enclomiphene

Enclomiphene (the active isomer of clomiphene) is newer and more potent. It's available in some clinics but less common in the UK than clomiphene.

Protocol: 12.5–25 mg daily.

Advantages over clomiphene:

Shorter half-life (less accumulation)
Less oestradiol elevation

Disadvantages:

Less available
More expensive
Still doesn't work during TRT

HCG + TRT: Key Monitoring

If you're on TRT + HCG, monitoring should include:

Baseline:

Semen analysis (if fertility is a priority)
Testicular size (clinical exam or ultrasound)
Testosterone, LH, FSH

At 4–6 weeks:

Testicular response (clinical exam — should not be atrophied)
Oestradiol (HCG can increase it)

Ongoing (every 3–6 months):

Testicular size and volume
Oestradiol
Semen analysis if fertility is a priority

Practical Approach: The Standard Protocol

If you want to preserve fertility on TRT, here's the evidence-based approach:

Start TRT (injection, gel, or patch) at standard doses (100–200 mg testosterone weekly, or equivalent)
Start HCG immediately (500–1000 IU, 2–3 times weekly) — don't wait to see if you need it
At 4–6 weeks: Get blood work (testosterone, LH, FSH, oestradiol) and clinical assessment (testicular size)
Adjust HCG based on response:
- Testes not atrophied? Continue dose.
- Testes atrophying? Increase HCG.
- Oestradiol very elevated (> 70 pg/mL)? Reduce HCG slightly or add aromatase inhibitor.
Optional: semen analysis at 8–12 weeks (to confirm sperm production is maintained)
Continue indefinitely if you're on long-term TRT and want to preserve fertility

Special Considerations

HCG-Induced Gynecomastia

Some men experience gynecomastia (breast tissue growth) on HCG due to HCG-stimulated oestradiol production in the testes.

Management:

Monitor oestradiol: Keep it < 60 pg/mL
Reduce HCG dose: Lower HCG → lower oestradiol
Add aromatase inhibitor: If oestradiol is elevated (though monitor closely to avoid over-suppression)

Typically, moderate HCG dosing with proper oestradiol management avoids this issue.

HCG Resistance or Poor Response

Rare, but some men respond poorly to HCG (testes don't respond well, or require very high doses). This may indicate underlying testicular dysfunction.

In these cases, HCG-priming (a short course of high-dose HCG before starting TRT) or alternative approaches might be discussed with your doctor.

Combining HCG With Aromatase Inhibitors

HCG raises oestradiol (because the stimulated testes produce some oestradiol). If you're also on an AI to manage aromatisation from exogenous testosterone, you now have two sources of oestradiol and need careful balancing.

Management: Work with a doctor who understands the interplay. Usually, modest HCG dosing avoids the need for strong AI therapy.

Cost-Benefit: Is HCG Worth It?

Cost: £40–100/month (additional to TRT cost).

Benefit: Preserved fertility, preserved testicular function and appearance.

For younger men or men wanting children: Absolutely worth it. It's insurance against needing years to recover fertility if you stop TRT.

For older men not wanting more children: Cheaper to skip it. But some men prefer to maintain normal testicular function regardless.

For men trialling TRT short-term: Probably unnecessary (but discuss with your doctor).

Bottom Line

HCG is essential if you want to maintain fertility on long-term TRT. Taken alongside TRT, HCG preserves testicular function and spermatogenesis, meaning you can remain fertile while replacing testosterone.

Standard dosing is 500–1000 IU, 2–3 times weekly via subcutaneous injection. It's inexpensive (added cost to TRT), straightforward to administer, and well-tolerated.

If you're on TRT and ever think you might want biological children, ask your clinic about HCG. It's far easier to maintain fertility throughout TRT than to recover it after years of TRT-induced azoospermia.

Most modern TRT clinics now include HCG as standard. If yours doesn't offer it, ask why, and consider switching to one that does.