Key takeaways:
Semaglutide has been linked to two rare types of cancer.
The most up-to-date research hasn’t found a link between semaglutide and an increased risk of cancer.
It’s possible that semaglutide can help lower the risk of certain cancers that are associated with higher weight.
Every medication has the potential for unwanted effects. These might include interactions with other medications, minor side effects, or serious long-term health consequences. Semaglutide — a treatment for diabetes and weight loss — is no exception.
You may have heard that semaglutide (Wegovy, Ozempic, Rybelsus) might raise the risk of cancer. There’s even an FDA boxed warning about its possible link to a rare type of thyroid tumor. But how big is this risk? And does semaglutide increase the risk of any other types of cancer? Here’s what you need to know.
Which cancers are semaglutide associated with?
Two types of cancer have been studied in connection with semaglutide: a specific type of thyroid cancer and pancreatic cancer. So far, the data doesn’t show a cause-and-effect relationship. In other words, semaglutide doesn’t cause thyroid or pancreatic cancer based on available studies.
Search and compare options
But these cancer types are very rare. So, it may be too soon to find a relationship. Ongoing research may provide more answers in the future.
Thyroid cancer
Semaglutide has a black box warning about a possible link to a rare thyroid cancer called medullary thyroid cancer (MTC). You may also see this called a C-cell tumor. This warning isn’t specific to semaglutide. Other medications in this same class, called glucagon-like peptide-1 receptor agonists (GLP-1 RAs), have the same warning.
The thyroid gland, located in your neck, makes and releases certain hormones that are important to many functions in your body. There are four types of thyroid cancer, and medullary thyroid cancer is the rarest. It happens when the hormone-producing C cells grow out of control. This is the type linked to GLP-1 RAs.
This link between semaglutide and C-cell tumors was discovered during safety studies in rodents that were given semaglutide. But researchers haven’t seen the same effect in humans. Follow-up studies suggest that MCT happens in fewer than 1% of people, meaning the risk seems to be very low.
The largest review of semaglutide, which included tens of thousands of people, found no increased risk of any type of cancer. Researchers rated the evidence for this conclusion as high quality.
Pancreatic cancer
Medications like semaglutide affect different parts of your digestive system. This includes your pancreas, the organ near your stomach that releases insulin.
Some older GLP-1 medications — like exenatide (Byetta) and sitagliptin (Januvia) — were once thought to increase the risk of pancreatitis and pancreatic cancer. Because of this, researchers looked into whether semaglutide carried the same risk.
But so far, large studies haven’t been able to find a link to pancreatitis or pancreatic cancer. One study found no increased cancer risk in people taking GLP-1 medications for diabetes. Another review found similar results when looking at people taking semaglutide for all indications, including weight loss. Both the FDA and the European Medicines Agency have also come to the same conclusion.
How does semaglutide affect potential cancer risk?
Many cells in your body have GLP-1 receptors, so medications like semaglutide can affect many different organs. Rodents, in particular, have more GLP-1 receptors in their thyroid cells. When activated, these receptors kick off a cascade that leads to C-cell overgrowth. This might explain the increased cancer rates seen in rodents given semaglutide.
How does weight impact your cancer risk? Research shows that certain types of cancer are more common in people with a higher weight.
Does Ozempic cause gallbladder issues? It might increase your risk of gallstones and gallbladder infections — but this risk is still relatively small.
How long do you need to take Wegovy? Most people need to take Wegovy for the long term to maintain weight loss.
As for your pancreas, semaglutide increases the number of beta cells in your pancreas. These cells secrete insulin, which helps control blood sugar levels. This effect is one reason this medication helps people with diabetes.
But even though semaglutide can increase growth of certain cells, researchers are still trying to understand semaglutide and its effects better. For now, there’s not enough information to know if or how it affects cancer risk in humans.
Can semaglutide help prevent any types of cancer?
It’s possible. Some types of cancer are more likely in people with excess body weight. Experts aren’t exactly sure why. They’re testing different theories, including whether losing extra body weight could also lower cancer risk.
A recent study supports this theory. Researchers found that people with body mass index of 35 or higher who took GLP-1 RAs had a 39% lower risk of weight-related cancers than those who didn’t take them. Interestingly, people who had bariatric surgery had only a 22% lower risk, even though they lost more weight. This could suggest that GLP-1 RA treatment might lower cancer risk in ways beyond just weight loss.
Of course, it’s still too early to say if semaglutide or similar medications can prevent cancer. But expect more to come in this area.
Frequently asked questions
It’s too early to tell. GLP-1 receptors can be found on many different cell and tumor types. Scientists are studying how these receptors affect cell growth and death in the lab. For example, GLP-1 receptors are linked to better survival rates in bladder cancer cells, but the opposite is true for stomach cancer cells.
Semaglutide shouldn’t be taken by people who have:
A personal or family history of medullary thyroid cancer
A rare genetic disorder called multiple endocrine neoplasia syndrome type 2 (MEN2)
Had an allergic reaction to semaglutide in the past
As of now, there are no other firm reasons to avoid (contraindications) semaglutide.
Semaglutide is still a relatively new medication, so researchers are continuing to study its long-term effects.
That said, every person is different and has different treatment goals. If semaglutide is working for you — whether that’s for diabetes or weight management — you might need to take it long term. Your healthcare team can help you decide what’s best for you.
It’s too early to tell. GLP-1 receptors can be found on many different cell and tumor types. Scientists are studying how these receptors affect cell growth and death in the lab. For example, GLP-1 receptors are linked to better survival rates in bladder cancer cells, but the opposite is true for stomach cancer cells.
Semaglutide shouldn’t be taken by people who have:
A personal or family history of medullary thyroid cancer
A rare genetic disorder called multiple endocrine neoplasia syndrome type 2 (MEN2)
Had an allergic reaction to semaglutide in the past
As of now, there are no other firm reasons to avoid (contraindications) semaglutide.
Semaglutide is still a relatively new medication, so researchers are continuing to study its long-term effects.
That said, every person is different and has different treatment goals. If semaglutide is working for you — whether that’s for diabetes or weight management — you might need to take it long term. Your healthcare team can help you decide what’s best for you.
The bottom line
Semaglutide is a common treatment option for Type 2 diabetes and weight management. While early concerns were raised of a potential link to thyroid and pancreatic cancers, extensive research doesn’t support these links. It’s possible that GLP-1 RAs, like semaglutide, may reduce the risk of certain weight-related cancers, but more research is needed to know for sure.
Why trust our experts?
References
ASCO Daily News. (2024). Both GLP-1 receptor agonists and bariatric surgery lower the risk of weight-related cancer in patients with obesity. American Society of Clinical Oncology.
Cao, C., et al. (2020). GLP-1 receptor agonists and pancreatic safety concerns in type 2 diabetic patients: Data from cardiovascular outcome trials. Endocrine.
Doyle, M. E., et al. (2006). Mechanisms of action of GLP-1 in the pancreas. Pharmacology & Therapeutics.
Egan, A. G., et al. (2014). Pancreatic safety of incretin-based drugs — FDA and EMA assessment. The New England Journal of Medicine.
Elashoff, M., et al. (2011). Pancreatitis, pancreatic, and thyroid cancer with glucagon-like peptide-1–based therapies. Gastroenterology.
Feier, C. V. I., et al. (2024). Assessment of thyroid carcinogenic risk and safety profile of GLP1-RA semaglutide (Ozempic) therapy for diabetes mellitus and obesity: A systematic literature review. Molecular Sciences.
Ibrahim, S. S., et al. (2024). The effect of GLP-1R agonists on the medical triad of obesity, diabetes, and cancer. Cancer and Metastasis Reviews.
Knudsen, L. B., et al. (2010). Glucagon-like peptide-1 receptor agonists activate rodent thyroid C-cells causing calcitonin release and C-cell proliferation. Endocrinology.
MyPART. (2019). Medullary thyroid cancer (MTC). National Cancer Institute.
Nagendra, L., et al. (2023). Semaglutide and cancer: A systematic review and meta-analysis. Diabetes & Metabolic Syndrome: Clinical Research & Reviews.
National Cancer Institute. (n.d.). Multiple endocrine neoplasia type 2 syndrome. National Institutes of Health.
Smits, M. M., et al. (2021). Safety of semaglutide. Frontiers in Endocrinology.
Ungvari, Z., et al. (2025). Prognostic impact of glucagon-like peptide-1 receptor (GLP1R) expression on cancer survival and its implications for GLP-1R agonist therapy: An integrative analysis across multiple tumor types. GeroScience.
