Dr. Johnston reviews a 2024 study of 1.65 million people with type 2 diabetes in which GLP-1 use was associated with lower risk of 10 of 13 obesity-related cancers compared with insulin, a 2025 comparison with bariatric surgery, and a laboratory finding involving natural killer cells. The studies are observational and cannot prove GLP-1 drugs prevent cancer.
Missed the first video? Watch Part 1. Read Dr. Johnston's full article: GLP-1 Medications and Cancer.
Weight loss. It's drama, as one episode of The Biggest Loser demonstrates. It's big money. It boosts self-esteem. It prevents heart attacks and strokes. And as research increasingly demonstrates, it reduces the risk of cancer.
In part one, we mentioned an 86,000 patient study showing that weight loss was associated with a significant reduction in 13 types of cancers. But the sheer size of the study I'm going to focus on today really got my attention. 1.65 million people.
In 2024, researchers published a study in the Journal of American Medical Association involving 1.65 million people with type 2 diabetes. They examined 13 cancers and tumors associated with obesity and compared people prescribed GLP-1 medications with patients prescribed insulin. GLP-1 use was associated with significantly lower risks of 10 of those 13 cancers.
Listen to these numbers. Gallbladder cancer 65% lower. Pancreatic cancer 59%. Liver cancer 53%. Ovarian cancer 48%. Colorectal cancer 46%, multiple myeloma 41%, esophageal cancer 26%, kidney cancer 24%, and meningioma was 63% lower in patients taking GLP-1 compared to those on insulin for their diabetes.
These are remarkable associations. This was an observational study and not a randomized cancer prevention trial. So we cannot say these medicines prevent cancer.
A separate 2025 study followed 6,350 people with obesity and diabetes for about 7 and 1/2 years. Now surgery produced greater weight loss. But when they accounted for weight loss, researchers estimated a 41% lower relative risk of obesity related cancers with medications compared to surgery. That suggests these drugs might offer protection beyond simply shedding pounds.
And there's a possible clue as to why. In laboratory experiments, exposing natural killer cells directly to GLP-1s increased their cancer fighting signals. These immune cells help recognize and destroy cancer cells. That offers a possible biological explanation for what researchers are seeing.
Large human studies are showing strong associations between the GLP-1s and the reduction in cancer risk beyond the weight loss alone. In a separate study, researchers estimated that a GLP-1 associated 10% weight reduction across eligible Americans could potentially avert approximately 1.22 million obesity related cancer cases by 2050.
From diabetes treatment to obesity treatment and now a possible role in cancer prevention. Here's the research. You decide.
Educational research summary, not medical advice. Talk with your oncologist and pharmacist before starting, stopping or changing any treatment or supplement.