Gonadorelin vs Kisspeptin vs HCG: Are They Necessary on TRT?

[Disclaimer: This article is for educational purposes only. Always consult with a qualified healthcare provider before starting any peptide protocol.]

Long-time followers of the Jay Campbell ecosystem KNOW that testosterone replacement therapy (TRT) alone is not a complete protocol.

The question I hear most from men has to do with all the other things to use as ancillary add-ons:

“Jay, do I actually have to add hCG, gonadorelin, or kisspeptin to my protocol… and if so, which one?”

Here’s everything you actually have to know the ongoing “Gonadorelin vs Kisspeptin vs HCG” debate.

Itdepends on WHERE in your hormonal cascade the problem actually lives, and what you want to preserve.

Most clinicians default to hCG because it’s familiar, FDA-approved, and easy to prescribe.

But this is the lazy approach to hormonal optimization.

Kisspeptin, gonadorelin, and hCG work at completely different levels of your reproductive axis.

Use the wrong tool at the wrong level, and you’ll end up creating downstream problems that never had to exist in the first place. 

I’ve used all three across decades of personal experimentation and hormone optimization work — and coached thousands of men through using them inside the Fully Optimized Health community.

And now, I AM distilling my experiences into this short article.

Quick Takeaways

• Kisspeptin acts at the hypothalamus, gonadorelin acts at the pituitary, and hCG acts directly at the gonads
• Men on TRT who want to preserve testicular function and fertility should trial Kisspeptin or gonadorelin BEFORE defaulting to hCG, i.e. always start upstream and work down
• Kisspeptin triggers natural GnRH release and may reduce ovarian hyperstimulation risk in IVF compared to hCG
• Gonadorelin restores pulsatile signaling without bypassing your axis
• hCG mimics LH and works even when your hypothalamus or pituitary is suppressed, but chronic use can desensitize receptors
• The key is matching the tool to YOUR physiology and current axis status, rather than defaulting to what is most accessible. 

The Mechanistic Reality Few Understand

Your reproductive axis runs top to bottom, and all 3 compounds intervene at completely different levels.

Kisspeptin binds to KISS1R receptors in the hypothalamus to stimulate endogenous GnRH release.

It’s the most upstream intervention available, working WITH your physiology rather than around it.

Gonadorelin is synthetic GnRH that GnRH receptors on pituitary gonadotrophs, triggering LH and FSH secretion.

It replaces or supplements natural GnRH pulsatility, making it one step downstream from Kisspeptin.

hCG bypasses the entire hypothalamic-pituitary axis and binds directly to LH receptors on Leydig cells (in men) or theca cells (in women), mimicking LH to drive steroidogenesis and gametogenesis.

If your hypothalamus and pituitary are functional, kisspeptin or gonadorelin can preserve physiological signaling.

But if they’re suppressed, as is the case with prolonged TRT or anabolic steroid use, hCG may be the only viable option to maintain testicular function.

Kisspeptin: The Upstream Controller

I’ve been talking about kisspeptin’s role in hormone optimization since before most clinicians had even heard of it.

It regulates puberty and fertility at the highest level of the axis.

Here’s some of the evidence we’ve accumulated thus far:

• A single injection of kisspeptin-10 induces a rapid LH surge that matches the body’s natural pulsatile pattern, peaking approximately 5 hours post-injection and returning to baseline within 12-14 hours.
• When infused over 20+ hours, kisspeptin elevates LH pulses and testosterone while preserving natural circadian rhythms (something flat-dose hCG cannot do).
• In IVF protocols, kisspeptin-54 triggered oocyte maturation in 95% of women at high risk of OHSS, with live birth rates of 45% per transfer and ZERO cases of moderate, severe, or critical ovarian hyperstimulation syndrome (Abbara et al., 2015, Journal of Clinical Endocrinology & Metabolism).
• Kisspeptin reduces OHSS risk because it creates a more physiological LH surge rather than the supraphysiological stimulation associated with hCG, and a 2022 review confirmed the odds of developing OHSS were 33.6 times higher following hCG compared to kisspeptin.

The big limitation with kisspeptin is the fact its effectiveness depends entirely on a responsive HPG axis.

If your hypothalamus or pituitary is suppressed, the results you achieve will be limited.

For men on TRT who still have a functional axis, or for men who want to maintain fertility while optimizing hormones, kisspeptin is one of the most intelligent tools available.

I recommend 125 mcg daily taken 1 hour before bed, cycled 30 days on and 30 days off.

Gonadorelin: The Pulsatile Solution

Gonadorelin is FDA-approved synthetic GnRH.

And it’s massively underutilized due to logistical complexity, rather than a lack of efficacy.

However, continuous exposure desensitizes pituitary receptors.

This is the same mechanism that makes GnRH agonists like leuprolide effective for prostate cancer suppression, whereby you “flood” the receptors until they shut down.

Therefore, gonadorelin MUST be administered in pulses to mimic natural physiology.

When used correctly, pulsatile GnRH therapy achieves fertility outcomes comparable to hCG + FSH in congenital hypogonadotropic hypogonadism, while restoring natural axis signaling.

It also produces a more balanced LH/FSH ratio compared to kisspeptin, which tends to preferentially drive LH… making it particularly important when spermatogenesis is the goal.

For men on TRT who aren’t responding well to hCG, or who want to preserve testicular function without adding another downstream compound, gonadorelin deserves serious consideration.

Pulsaltile delivery may be harder to implement than a simple injection schedule, but that doesn’t make it the wrong or inferior approach. 

hCG: The Downstream Workhorse

hCG is the compound every TRT clinic is intimately familiar with.

It works as it’s supposed to, even when the upstream axis is completely suppressed.

hCG directly stimulates Leydig cells for testosterone production and supports spermatogenesis, making it the go-to for men on TRT seeking fertility preservation.

In women, it remains the gold standard for ovulation triggering in IVF, although kisspeptin may be changing that equation for high-risk patients.

I’ve written extensively about hCG and its role in testosterone optimization, and the compound has earned its place in the toolbox.

But it comes with its own share of limitations:

• Desensitizes LH receptors with chronic use of high doses, i.e. the very receptors you’re trying to stimulate.
• Can elevate estrogen levels in men through increased aromatization.
• Significantly increases OHSS risk compared to kisspeptin-based triggering in women
• Does NOT restore pulsatility or feedback regulation (since hCG bypasses natural signaling entirely)

hCG can be useful in cases where you have to “force” the system instead of working with it.

But it’s a when you use it by default because you don’t understand the alternatives.

Gonadorelin vs Kisspeptin vs hCG: When to Use Each on TRT

Most articles will steer you the wrong way by giving you a list without context.

Here’s how I think about deploying these three compounds for TRT users specifically:

Use Kisspeptin If:

• Your HPG axis is still responsive and you want to preserve upstream signaling while on TRT
• You’re looking to boost testosterone production and retain fertility without bypassing the axis
• You’re a woman pursuing IVF and want to reduce OHSS risk
• You want to enhance sexual function and arousal through physiological pathways

Use Gonadorelin If:

• You need pulsatile GnRH replacement while on TRT
• You want balanced LH/FSH stimulation (important for spermatogenesis)
• You want to preserve axis integrity without a downstream compound
• hCG isn’t giving you the testicular response you want

Use hCG If:

• Your axis is suppressed from long-term TRT or steroid use and needs direct gonadal stimulation
• You need reliable, proven fertility preservation while on testosterone
• You’re in a standard IVF protocol where hCG triggering is appropriate

Stacking (Context-Dependent):

• TRT patients often combine low-dose hCG with periodic gonadorelin to maintain both testicular function and axis responsiveness
• High-responder IVF patients may substitute kisspeptin for hCG to eliminate OHSS risk
• Men with intact axes should trial kisspeptin or gonadorelin BEFORE escalating to hCG — always start upstream and work down

The Evidence Gaps Worth Acknowledging

We lack large head-to-head trials directly comparing all three compounds in the same population.

hCG has the longest safety track record, but also carries known desensitization risks with chronic use.

Kisspeptin data is extremely promising, particularly for IVF safety, but we still need larger and longer-term studies.

Gonadorelin is proven but logistically demanding to use, which limits its adoption.

But as I said before, convenience should not necessarily dictate the protocol and mechanisms should be better prioritized.

Monitoring and Practical Considerations

All three compounds require bloodwork monitoring.

Kisspeptin: Track LH, FSH, and testosterone response.

My current dosing recommendation can be found in the Peptide Cheat Sheet.

Gonadorelin: Must be dosed in a pulsatile fashion, as continuous dosing will suppress rather than stimulate.

Monitor LH and FSH to confirm pituitary response.

hCG: Monitor estrogen levels in men (OHSS risk markers for women), as hCG drives intratesticular testosterone and this can increase aromatization.

If you’re new to peptide protocols, start with my Peptide Reconstitution Course to make sure you’re handling these compounds correctly.

The Bottom Line

Gonadorelin, kisspeptin, and hCG are NOT interchangeable, and none of them should be added to a TRT protocol without understanding WHERE in your axis the problem lies:

• Kisspeptin = upstream controller (hypothalamus)
• Gonadorelin = pulsatile pituitary stimulator
• hCG = downstream gonadal activator

Most clinicians default to hCG because it’s simple and they never learned the mechanistic differences that exist with the other two compounds.

But after reading this article, now you understand what they don’t.

Use the most upstream tool your physiology will respond to, preserve natural signaling whenever possible, and ONLY bypass the axis when you have to.

This is how you graduate from hormone management to hormone optimization.

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