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The GLP-1 Mistake Everyone Is Making

The GLP-1 Mistake Everyone Is Making

Get this checked first

Hunter Williams
October 02, 2025

Happy Thursday!

Every week, I get messages from readers who are excited about starting GLP-1s.

And while I love that these therapies are finally bringing mainstream attention to obesity and metabolic disease, I also see the same mistake over and over.

People jump straight into GLP-1s without ever taking a hard look at their hormones.

If your testosterone is low, your GLP-1 journey is like driving with the parking brake on.

You’ll lose some weight, sure, but you’ll also risk losing muscle, energy, and vitality in the process.

GLP-1s alone will not give you sustainable fat loss for life.

They were never designed to fix hormonal deficiencies.

They work on appetite, satiety, and blood sugar, but if the hormonal foundation is broken, the results are incomplete.

And sadly, many men and women start GLP-1s in a state of low testosterone without realizing it.

This sets them up for poor long-term outcomes.

Let’s examine why.

GLP-1s Are Powerful, but Incomplete

There’s no denying GLP-1 receptor agonists have revolutionized obesity care.

In a 48-week trial, retatrutide produced mean body-weight reductions of 22.8% and 24.2% with doses of 8 mg and 12 mg, respectively.

That’s unprecedented for a non-surgical intervention.

And beyond the scale, GLP-1s lower A1c, reduce cardiovascular risk, and improve insulin sensitivity.

However, it’s not all unicorns and rainbows.

In many of these studies, 30–40% of the total weight loss came from lean mass.

Muscle is your metabolic engine.

It drives energy expenditure, insulin sensitivity, and physical performance.

So while GLP-1s are powerful, they can also accelerate sarcopenia if we’re not careful.

You must ensure that you’re protecting your lean mass while using them.

And this is exactly where hormones come into play.

Testosterone

When most people think of testosterone, they think about sex drive, libido, or muscle building.

But testosterone is also one of the most important metabolic hormones in the body.

Low testosterone is tightly linked with obesity, insulin resistance, and type 2 diabetes.

Obese men have, on average, 30% lower testosterone than their lean peers.

In one study, obese men put on a low-calorie diet lost fat but also lost significant lean mass.

The men who received testosterone replacement, however, lost almost exclusively fat while preserving their muscle.

In fact, their ability to regain muscle during maintenance was enhanced.

That’s the difference testosterone makes.

It changes the quality of weight loss.

TRT also improves insulin sensitivity, lowers visceral fat, and reduces A1c in men and women with diabetes.

In other words, it hits many of the same targets as GLP-1s, but through a different pathway.

Synergy

Let’s talk about why GLP-1s and testosterone work better together than apart.

GLP-1s create a calorie deficit by reducing appetite and improving insulin function.

Testosterone, on the other hand, stimulates muscle protein synthesis, increases resting energy expenditure, and blocks fat accumulation.

When you combine the two, you cover both sides of the energy balance equation.

GLP-1s make you eat less and burn more glucose.

Testosterone makes sure the weight you lose comes primarily from fat while preserving lean tissue.

It’s the difference between ending a six-month GLP-1 cycle feeling lighter but weaker, versus ending it leaner, stronger, and more insulin sensitive than you’ve been in years.

A 2019 hypothesis paper in Medical Hypotheses predicted this synergy exactly, arguing that sex hormone therapy and GLP-1s together would accelerate body weight reduction.

Fast forward, and the data now back it up.

Clinical Evidence

One of the most striking examples comes from a 2024 study presented at the Endocrine Society.

Twenty men with age-related low testosterone received weekly GLP-1 injections plus biweekly HCG therapy (to stimulate testosterone production).

TRT would be my recommendation, but HCG is better than nothing.

Over 18 months, their body fat percentage dropped from 24.6% to 18.1%.

BUT their lean mass actually increased, something you almost never see in weight-loss trials.

Compare that to GLP-1 monotherapy, where muscle typically declines.

These men experienced the fat loss benefits of GLP-1s, along with the anabolic preservation of testosterone.

Their fasting glucose, fasting insulin, and HbA1c all improved as well, confirming the metabolic synergy.

Clinicians noted that the muscle loss seen with GLP-1s alone was improved by testosterone optimization.

And this isn’t an isolated observation.

Other randomized trials show TRT in obese men preserves muscle during dieting, while GLP-1s independently improve glycemia.

Why Hormones First

Don’t make the mistake of rushing into GLP-1 therapy before you’ve looked at your hormones.

If your testosterone is low, start there. Correct the deficiency first, then layer in GLP-1 therapy.

That way, you’re operating from a foundation of hormonal optimization.

Think of it like building a house. GLP-1s are a powerful remodeling tool, but testosterone is the foundation.

Without the foundation, the remodel collapses in on itself.

With it, everything you build is stable and sustainable.

In practical terms, this means:

Testing your testosterone before starting GLP-1s.
If you’re deficient, optimizing with TRT under medical supervision.
Then using GLP-1 therapy strategically to accelerate fat loss.

This sequence sets you up for sustainable fat loss because your metabolism, muscle mass, and hormones are aligned.

The Bigger Picture

What excites me most about the GLP-1 + testosterone synergy is that it goes beyond just dropping weight.

It improves sexual health, energy, motivation, and even cardiovascular markers.

GLP-1s reduce heart attack risk. Testosterone improves endothelial function and insulin sensitivity. Together, they represent a comprehensive metabolic upgrade.

And the beauty is, we already have the tools. They just need to be applied intelligently.

Final Thoughts

If you’ve been considering GLP-1 therapy, or if you’ve already started and felt the benefits but also some drawbacks, stop and ask if you have evaluated your hormones first?

If the answer is no, you’re leaving results on the table.

That’s why Jay Campbell and I built Quantum Testosterone.

Quantum Testosterone | Jay Campbell

You think low T is the enemy?

jaycampbell.com/quantumt

Our new course shows you exactly how to optimize testosterone therapy and, yes, how to integrate GLP-1s (specfically retatrutide) properly for sustainable fat loss that lasts for life.

We have an entire module dedicated to this synergy, breaking down the science, the protocols, and the mistakes to avoid.

Because at the end of the day, we all do this to reclaim our vitality, our energy, and our lives.

And when GLP-1s are combined with optimized testosterone, that vision becomes reality.

Best,

Hunter Williams