If you're on TRT, you've heard about hCG. It comes up in almost every forum thread, every clinic consultation, every "what else should I be taking?" conversation. And unlike a lot of the stuff that gets thrown around in those discussions, hCG actually has solid reasons behind it.
What hCG does
hCG (human chorionic gonadotropin) mimics luteinizing hormone (LH) — the hormone that tells your testes to produce testosterone and sperm. Once you start TRT, your body detects the external testosterone and stops producing its own LH. Your pituitary basically goes quiet. This is hypothalamic-pituitary-gonadal (HPG) axis suppression, and it's the reason TRT affects fertility and causes testicular shrinkage.
hCG picks up where your LH left off. It binds to the same receptors and keeps your testes working, even though your natural signalling has shut down (Cleveland Clinic).
Why bother?
Fertility. This is the main reason. TRT can tank sperm production — sometimes all the way to zero. If kids are on the horizon, or even a vague possibility, hCG keeps spermatogenesis going so you're not trying to restart everything from scratch later (Cleveland Clinic - Male Infertility). It's much easier to maintain than to recover.
Testicular size. Without LH stimulation, your testes shrink. Some men don't care. Others really do. hCG prevents it or reverses it (Mayo Clinic). We covered this in our side effects guide as well.
Intratesticular hormones. There's a reasonable argument that keeping some local testosterone production going supports other hormonal pathways — pregnenolone, DHEA — that exogenous testosterone alone doesn't cover. The evidence here is less clear-cut than the fertility angle, but plenty of men report feeling better with hCG in the mix.
Estrogen balance. A bit of a double-edged sword, honestly. hCG can improve the overall hormone profile for some men, but it also increases aromatisation. More on that in a minute.
Do you need it?
Maybe not. If you're not planning on having kids, testicular shrinkage doesn't bother you, and you feel good on TRT alone — there's no rule that says you have to add hCG. It's another medication, another cost, and more needles.
Where it becomes worth the conversation:
- You might want children at some point (even if it feels distant right now)
- Fertility has been a concern for you or your partner
- Testicular changes are getting to you, physically or mentally
- Your prescribing doctor has recommended it
If you're new to TRT altogether, our beginner's guide covers the fundamentals. For those already on therapy and sorting out the finer points, our protocol optimisation guide covers adjunct therapies more broadly.
Dosing
hCG is injected subcutaneously or intramuscularly, same as testosterone. The dose depends on what you're trying to achieve:
| Goal | Dose | Frequency |
|---|---|---|
| Maintenance / fertility | 250–500 IU | 2–3x per week |
| Standard protocol | 500–1,000 IU | 2–3x per week |
| Higher dose (doctor-supervised) | 1,000–2,000 IU | 2–3x per week |
Most clinics start at 500 IU twice a week and adjust from there. Higher isn't automatically better — pushing the dose up mostly just raises your estrogen without much additional benefit.
When to inject
Two schools of thought:
Same day as testosterone. Simpler. Fewer injection days. Some men prefer getting it all done at once.
Opposite days. Inject hCG on your off days from testosterone. The idea is more consistent receptor stimulation across the week. A lot of clinics lean this way.
Honestly, either works. Consistency matters more than which days you pick. Go with whatever you'll actually stick to.
Monitoring
hCG changes a few things in your blood work, so you'll want to pay attention to these during your regular labs:
Estradiol (E2) is the big one. hCG stimulates intratesticular aromatase, so your estrogen can climb higher than it would on TRT alone. Watch for water retention, breast tenderness, or mood shifts (PubMed).
Total and free testosterone may shift upward since hCG adds some endogenous production on top of your TRT dose. You might need to lower your testosterone dose slightly.
Semen analysis — if fertility is why you're on hCG, this is the only way to actually confirm it's working. Numbers on paper, not just a feeling.
Hematocrit — same as with TRT generally. Keep tabs on red blood cell counts.
Log your hCG doses alongside your TRT injections in TRT Monitor to spot how changes affect your labs and symptoms over time.
What can go wrong
Estrogen creep. The most common issue by far. hCG pushes estradiol up, and if you're already running on the higher side, it can tip you into symptomatic territory. Before reaching for an aromatase inhibitor, try adjusting your injection frequency or lowering your testosterone dose first. As we noted in our protocol guide, AIs should be a last resort (PubMed).
LH receptor desensitisation. At very high doses over long periods, there's a theoretical risk of burning out the LH receptors. At typical TRT-support doses (500–1,000 IU a few times a week), this isn't really a practical concern. It's more relevant to the aggressive fertility protocols that run well above those ranges.
Availability. Regulatory changes have made hCG harder to get from compounding pharmacies in some regions. Depending on where you are, sourcing might take some extra legwork. Worth checking with your clinic before assuming you can get it easily.
Storage is a pain. Reconstituted hCG needs to stay refrigerated and only lasts about 30–60 days once mixed. If you travel a lot or don't have a consistent routine, this can be annoying.
Cost. Another medication on top of your TRT. It adds up, especially if your insurance doesn't cover it.
Talking to your doctor
hCG needs a prescription. When you bring it up, have a clear idea of:
- What you're hoping it'll do (fertility? size? general wellbeing?)
- Your current TRT protocol and any side effects you're dealing with
- Whether your estradiol is already running high
- How you plan to source it
Your doctor should run baseline labs before adding hCG and schedule follow-ups to check your response (AAFP). If you're not sure what blood work to ask for, our blood work schedule covers it.
Wrapping up
hCG is worth considering if fertility matters to you — even as a future possibility — or if testicular atrophy is something you'd rather not deal with. It's not for everyone, and it does add complexity to your protocol. But for the men who need it, it solves problems that TRT alone can't.
Start with a conversation with your doctor. Track what happens in TRT Monitor so you've got actual data to work with, not just a vague sense of how things are going.