Popular Weight-Loss Drugs Like Wegovy Fail To Lower Obesity-Related Cancer Risks, Study Finds

Researchers analysed 48 previously-conducted trials which examined the safety and efficacy of GLP-1 drugs on people with type 2 diabetes, overweight, or obesity. These studies involved a total of more than 94,000 participants.

16 Dec 2025, 09:31 · www.ndtv.com

A recent study found that popular glucagon-like peptide-1 (GLP-1) receptor agonist drugs like Wegovy and Zepbound, have little to no impact on an individual's risk of obesity-related cancer. The study was published in the journal Annals of Internal Medicine. According to the World Health Organization (WHO), in 2022, about 2.5 billion adults were overweight, of which 890 million were living with obesity. Previous studies have shown how obesity increases an individual's risk of different types of cancers. However, the new study reveals that GLP-1 medications don't lower an individual's cancer risk. Obesity increases the risk of different types of cancers, including thyroid, pancreatic, breast, kidney, colorectal, esophageal, liver, gallbladder, ovarian, gastric, and endometrial cancer, among others.

Researchers analysed 48 previously-conducted trials which examined the safety and efficacy of GLP-1 drugs on people with type 2 diabetes, overweight, or obesity. These studies involved a total of more than 94,000 participants. Cho-Han Chiang, MD, MMSc, clinician investigator in the Department of Medicine in Mount Auburn Hospital at Harvard Medical School in Massachusetts, and corresponding author of this study told Medical News Today, "GLP-1 receptor agonists are now being used by millions of people worldwide for diabetes and obesity, yet their long-term cancer safety has remained uncertain."

Chiang added, "Early observational studies and case reports raised concerns about potential links with certain cancers (e.g. thyroid, pancreatic cancers)."

"At the same time, other observational studies have suggested a lower risk of certain cancers, particularly obesity-related cancers, with GLP-1RA use," he said. "This mixture of signals has contributed to uncertainty in the field and the need to investigate further."

The researchers chose to study obesity-related cancers because these cancers are strongly influenced by excess adiposity, chronic inflammation, and metabolic dysregulation. Chiang further said that obesity increases the risk of these malignancies, there are 13 types of cancer recognised as associated with obesity, and GLP-1 receptor agonists produce meaningful and sustained weight loss.

"This raises the question of whether GLP-1RAs could reduce the risk of obesity-related cancers. Recent observational studies have suggested possible protective associations - patients using GLP-1RAs appeared to have lower rates of certain obesity-related cancers. However, these are data from non-randomised studies with [the] possibility of confounding factors at play," Chiang noted.

"Our study pulls together cancer events across large randomised clinical trials to provide a more rigorous and comprehensive assessment of cancer risk with GLP-1RAs," he said. "It helps fill a critical gap for clinicians, regulators, and patients who must balance substantial metabolic and cardiovascular benefits against theoretical long-term cancer risks."

No Cancer Risk Reduction from GLP-1 Drugs

The researchers concluded that GLP-1 drugs probably had little to no impact on the risk for thyroid, pancreatic, breast, or kidney cancers. Chiang said, "Our results suggest that current GLP-1RA use does not appear to meaningfully increase short- to intermediate-term risk, but they do not rule out the possibility of effects, harmful or beneficial, over longer durations. Continued long-term surveillance will be essential."

Researchers also found that the evidence for colorectal, oesophageal and liver cancers was of low certainty and that the impact of GLP-1 drugs on gastric cancer risk was very uncertain. Chiang explained, "The significance of these findings is that they highlight areas where current evidence is simply too limited to draw firm conclusions, even across large randomised trials. For colorectal, oesophageal, liver, and gastric cancer, the number of events in trials was very small, and follow-up durations were relatively short."

Obesity's Cancer Link: What the Study Found

Chiang also speaks on whether GLP-1s offer any protection against obesity-related cancers. He said, "Based on our analysis of randomised trials, GLP-1 medications probably have little or no effect on obesity-related cancer risk within the follow-up periods studied. However, this does not rule out the possibility of a protective effect over longer durations. In fact, there are several reasons why a protective effect has been hypothesised."

"First, obesity is a major driver of several cancers through chronic inflammation, insulin resistance, and hormonal and metabolic pathways," Chiang detailed.

He further explained that GLP-1 receptor agonists produce substantial weight loss and improve metabolic health, which could theoretically reduce the incidence of obesity-related cancers over time. "Second, several recent observational studies have reported lower rates of certain cancers among GLP-1RA users."

"Because randomised trials to date have relatively short follow-up and few cancer events, they may not yet capture long-term or delayed protective effects," Chiang continued.

"From the perspective of current evidence, our study suggests that a clear protective effect has not yet been demonstrated in randomised data, but the possibility remains biologically plausible and supported by some real-world signals," said Chiang.

Disclaimer: This content including advice provides generic information only. It is in no way a substitute for a qualified medical opinion. Always consult a specialist or your own doctor for more information. NDTV does not claim responsibility for this information.

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