GLP-1 receptor agonists—such as semaglutide (Ozempic, Wegovy), tirzepatide (Mounjaro, Zepbound), and dulaglutide (Trulicity)—have revolutionized treatment for type 2 diabetes and obesity. But as their popularity surges, so do questions about long-term safety. Among the most pressing concerns: Do GLP-1 drugs increase the risk of cancer? This article explores the current scientific evidence, regulatory warnings, and what California patients should know before starting or continuing GLP-1 therapy.
What Are GLP-1 Drugs?
GLP-1 (glucagon-like peptide-1) receptor agonists mimic a natural hormone that:
- Stimulates insulin secretion
- Suppresses glucagon release
- Slows gastric emptying
- Reduces appetite
These effects help regulate blood sugar and promote weight loss. GLP-1 drugs are FDA-approved for type 2 diabetes and, in some cases, chronic weight management. They are typically administered via weekly injections or daily oral tablets.
Cancer Concerns: Where Did They Come From?
Initial concerns about cancer risk stemmed from animal studies and early post-marketing surveillance. Researchers observed:
- Thyroid tumors in rodents exposed to GLP-1 drugs
- Reports of pancreatitis, a known risk factor for pancreatic cancer
- Gastrointestinal side effects that raised questions about long-term organ impact
These findings prompted the FDA to require a boxed warning on many GLP-1 medications, especially regarding medullary thyroid carcinoma (MTC).
Thyroid Cancer: What the Evidence Shows
Animal Studies
Rodent studies showed an increased incidence of C-cell hyperplasia and medullary thyroid tumors when exposed to GLP-1 drugs. However, these findings may not translate to humans:
- Human thyroid C-cells have fewer GLP-1 receptors than rodents
- Clinical trials have not demonstrated a significant increase in thyroid cancer among GLP-1 users
Human Data
A 2024 review by City of Hope Cancer Center concluded:
- No direct causal link between semaglutide and thyroid cancer has been established
- The risk appears limited to individuals with MEN2 syndrome or a family history of MTC
FDA Warning
Despite inconclusive human data, the FDA mandates a warning label for GLP-1 drugs, advising against use in patients with:
- Personal or family history of MTC
- Multiple Endocrine Neoplasia syndrome type 2 (MEN2)
Pancreatic Cancer: Myth or Risk?
Pancreatitis Connection
GLP-1 drugs have been associated with acute pancreatitis, which can increase the risk of pancreatic cancer over time. However:
- Large cohort studies have not found a statistically significant increase in pancreatic cancer among GLP-1 users
- A 2025 review of over 70,000 patients found no elevated incidence of pancreatic cancer after 7 years of GLP-1 therapy
Regulatory Position
The European Medicines Agency and FDA have both reviewed the data and concluded:
- No causal link between GLP-1 drugs and pancreatic cancer has been established
- Monitoring is ongoing, especially for long-term users
Esophageal Cancer: A New Concern?
A 2025 Canadian study published in the Annals of Internal Medicine found that GLP-1 users were:
- 27% more likely to develop GERD (acid reflux)
- 55% more likely to experience GERD complications, including Barrett’s esophagus, a precursor to esophageal cancer
Key findings:
- Risk was higher among long-acting GLP-1 users
- Most complications involved Barrett’s esophagus
- Smokers and individuals with obesity were at greater risk
While the link is indirect, it raises important questions about gastrointestinal side effects and cancer risk.
Can GLP-1 Drugs Reduce Cancer Risk?
Surprisingly, some studies suggest GLP-1 drugs may offer protective benefits against certain cancers:
Ovarian Cancer
A 2025 retrospective cohort study found:
- GLP-1 users had a 55% lower mortality risk from ovarian cancer
- Benefits were consistent across age groups and treatment types
Obesity-Related Cancers
GLP-1 drugs may reduce the risk of up to 10 of 13 obesity-associated cancers, including:
- Colorectal
- Liver
- Kidney
- Pancreatic
- Endometrial
- Gallbladder
- Esophageal
- Ovarian
- Multiple myeloma
- Meningioma5
Mechanisms include:
- Reduced inflammation
- Improved insulin sensitivity
- Lower body fat percentage
What California Patients Should Consider
Risk Factors
Before starting GLP-1 therapy, discuss the following with your doctor:
- Personal or family history of thyroid cancer
- History of pancreatitis or gastrointestinal disorders
- Symptoms of acid reflux or Barrett’s esophagus
- Current cancer diagnosis or treatment plan
Monitoring
Patients on GLP-1 drugs should:
- Report persistent nausea, vomiting, or abdominal pain
- Undergo routine thyroid and pancreatic screening if at risk
- Monitor for signs of GERD or esophageal irritation
Legal Considerations
If you believe GLP-1 use contributed to a cancer diagnosis, consult a California toxic tort attorney. You may have grounds for:
- Product liability claims
- Failure-to-warn lawsuits
- Compensation for medical expenses and emotional distress
Final Thoughts
GLP-1 drugs are powerful tools for managing diabetes and obesity—but like all medications, they come with risks. While current evidence does not support a direct link between GLP-1 use and cancer, certain populations may face elevated risks. At the same time, these drugs may offer protective benefits against obesity-related cancers. California patients should weigh the risks and benefits carefully, consult their healthcare providers, and stay informed as new research emerges.
References
- GLP-1 drugs increase risk of acid reflux, GERD, study finds
- Veru survey highlights muscle loss concerns among GLP-1 users
- GLP-1 Receptor Agonists Show Promise as Adjunctive Treatment for Ovarian Cancer
- Can Semaglutide Cause Cancer? Know the Potential GLP-1 Risks – City of Hope
- Cancer Benefits and Risks From Ozempic, Wegovy – Memorial Sloan Kettering
- Weight Loss Injections and Cancer – MD Anderson Cancer Center
- 10 GLP-1 Side Effects You Should Know About – GoodRx
- Do GLP-1 Drugs Increase the Risk of Cancer? – GLP1.Guide