GLP-1s vs. Cancer

Happy Friday!

I hope you were able to enjoy a great Thanksgiving Holiday with your family.

This morning, I just dropped a brand-new podcast episode on Spotify about the connection between GLP-1 drugs and cancer risk.

The video is based on data from a massive study published in JAMA Oncology in August 2025.

This new paper looked at more than 86,000 adults with obesity over about a decade and asked a simple question.

What happens to cancer risk when people are on GLP-1s versus when they are not?

Today’s email is the written companion to the episode.

I will walk you through the numbers, what they actually mean, and how I think about GLP-1s as a preventative tool alongside everything else we do for longevity and health optimization.

Obesity and Cancer

We cannot talk about GLP-1s and cancer without calling out the elephant in the room.

Being overweight or having obesity is associated with at least 13 different cancers, and those cancers make up about 40% of all cancers diagnosed each year in the United States.

Sit with that for a second.

Out of 100 people who get cancer, about 40 have a cancer that is strongly linked to excess body fat and metabolic dysfunction.

That list includes endometrial, breast (post-menopause), ovarian, colorectal, liver, kidney, pancreas, esophageal adenocarcinoma, thyroid, meningioma, and multiple myeloma.

If heart disease is the number one killer and cancer is number two, obesity is sitting in the background feeding both fires.

Most people still think of cancer as a random lightning strike from the sky.

Genetics. Bad luck. Maybe environmental toxins.

The data says something much more brutal.

In a huge percentage of cases, cancer is an expression of long-standing metabolic disease.

GLP-1s Beyond Weight Loss

GLP-1 receptor agonists started as diabetes drugs.

They mimic a gut hormone that tells your pancreas to release insulin, your stomach to slow down emptying, and your brain that you are full.

Semaglutide at obesity doses averages around 15% body-weight reduction. The newer dual and triple agonists like tirzepatide and retatrutide are pushing 20–24% in some studies.

That kind of weight loss used to be bariatric-surgery territory. And we know from bariatric data that when people with severe obesity lose more than 20% of their total weight, their risk of developing cancer drops by about 50% compared to those who do not lose that much.

Now, stack on top of that what GLP-1s do metabolically. Lower fasting insulin and glucose. Better A1c. Less visceral fat.

Blood pressure and triglycerides come down. Inflammation markers like CRP, IL-6, and TNF-α go down as well.

The Big Study

In this new study, they took 43,317 adults on GLP-1s and matched them 1:1 with 43,315 similar adults who never used GLP-1s.

All were overweight or obese, the average age was about 52, about 68% were women, and none had a prior history of cancer.

Then they followed them and tracked 14 cancers.

Thirteen were classic obesity-related cancers plus lung cancer.

Over the follow-up period, the incidence of cancer was 13.6 per 1,000 persons in the GLP-1 group and 16.4 per 1,000 persons in the non-GLP group. That works out to a 17% lower overall cancer risk for GLP-1 users.

Roughly one fewer cancer case per 1,250 people per year on GLP-1s, which is massive when you zoom out to millions of people who qualify for these drugs.

Granular Data

Overall risk is cool. But the really mind-blowing part is what happened when they broke it down by cancer type.

In women on GLP-1s, endometrial (uterine) cancer dropped by about 25% compared to nonusers.

Ovarian cancer was where my jaw hit the floor. GLP-1 users had a 47% lower risk of ovarian cancer.

That is almost cutting risk in half in a cancer that is notoriously hard to detect early and closely tied to metabolic dysfunction and inflammation.

Then you have meningioma, a type of brain tumor.

In GLP-1 users, risk was 31% lower.

Read those numbers again.

25% lower uterine cancer. 47% lower ovarian cancer. 31% lower brain tumors.

We are still in correlation, not causation territory, but when the effect size is that big, and it lines up perfectly with what we know about obesity and hormone-sensitive cancers, the signal is hard to ignore.

Mechanisms

Once you understand how obesity drives cancer, the study stops being surprising.

Chronic high insulin creates a constant growth signal that tells cells to divide and not die.

That is literally the environment tumors love.

Elevated fasting insulin is a ticking time bomb. It will not cause cancer in everyone, but it sets the stage.

Layer on chronic inflammation. Fat tissue leaks pro-inflammatory cytokines, such as IL-6 and TNF-α, that cause DNA damage and blunt immune surveillance.

GLP-1 RAs have been shown in meta-analysis to lower CRP, IL-6, and TNF-α in people with type 2 diabetes.

Now plug GLP-1s into that picture.

You lose 10–15% of your body weight.

You shrink inflammatory fat depots.

You drop fasting insulin and improve glucose control.

You cool down systemic inflammation.

It is metabolic jiu-jitsu.

You are using the same tools pharma built for diabetes and obesity to quietly cut off many of the pathways that feed cancer.

Prevention

We already know obesity drives roughly 40% of cancers.

We already know bariatric-level weight loss can cut certain cancer risks by about half.

GLP-1s give us a scalable way to get a meaningful chunk of that weight loss and metabolic improvement without surgery.

When you combine that with lifting weights, performing cardio, getting lean protein and whole food, fixing sleep, and avoiding alcohol, you are stacking the deck massively in your favor.

The future of “Medicine 3.0” is going to be metabolic.

Heart disease. Cancer. Neurodegeneration.

They are all different faces of the same underlying dysfunction.

GLP-1s, peptide therapy, and hormone optimization are tools to go upstream and keep the body from ever reaching the place where cancer becomes almost inevitable.

That is how I plan to use them for my family and me over the coming decades.

Final Thoughts

We are just at the beginning of seeing how powerful GLP-1s are as a cornerstone of prevention.

Cancer is the tip of the iceberg.

My mission is to help you use these tools intelligently so you can become the highest-realized version of yourself, not just someone who “lost a few pounds.”

Have a great weekend!

Best,

Hunter Williams

Further References

1. GLP-1 Receptor Agonists and Cancer Risk in Adults With Obesity. JAMA Oncology. 2025.

2. The effect of GLP-1 receptor agonists on circulating inflammatory markers in type 2 diabetes: a meta-analysis. Diabetes Obesity and Metabolism. 2025.