Ozempic and Cancer Risk: What 2025–2026 Evidence Really Shows

TL;DR: In a 2025 meta-analysis of 50 studies, GLP-1 receptor agonists were not associated with increased overall cancer risk.

The 2025–2026 evidence on Ozempic (semaglutide) and cancer risk is reassuring overall: large-scale reviews of randomized controlled trials (RCTs) show no meaningful increase in risk for thyroid, pancreatic, or other obesity-related cancers. Human data from tens of thousands of participants do not support the rodent-based concerns that prompted early FDA warnings. Some observational studies even hint at possible protective effects against certain cancers (likely tied to weight loss and metabolic improvements), but high-quality RCT evidence points to a neutral effect. Longer-term studies (≥5 years) are still needed for full certainty, as most trial follow-up has been under 2 years.

Thyroid Cancer: The Main Historical Concern, Now Largely Addressed

Rodent studies showed dose- and duration-dependent thyroid C-cell tumors (including medullary thyroid carcinoma, or MTC) at clinically relevant exposures, leading to the FDA’s boxed warning and contraindication in people with personal/family history of MTC or multiple endocrine neoplasia syndrome type 2 (MEN2). Human C-cells have far lower GLP-1 receptor density and different signaling, so the risk does not translate well.

2025–2026 human evidence shows no significant increase:

- A December 2025 systematic review and meta-analysis in *Annals of Internal Medicine* (48 placebo-controlled RCTs, 94,245 participants, median 70-week follow-up; semaglutide in 42% of trials) found little or no effect on thyroid cancer risk (moderate certainty). Absolute risk was very low (~0.14% in GLP-1 users vs. 0.07% in placebo).

- The February 2026 Clayman Thyroid Center white paper reviewed multinational RCTs, real-world cohorts, and post-marketing data: no convincing evidence that GLP-1 receptor agonists (including semaglutide) cause common thyroid cancers (papillary, follicular, or oncocytic/Hürthle cell). Early signals often reflect detection bias from increased monitoring, not causation. MTC remains rare with no established human causal link.

- Additional 2025–2026 analyses (including large trial pools and real-world databases) reported thyroid cancer incidence <1% in semaglutide users, with hazard ratios near 1.0 and no sustained elevation.

Bottom line for thyroid: The rodent-based warning remains on labels, but current human data do not indicate a real-world risk for most patients. No extra routine thyroid monitoring beyond standard care is generally needed.

References for thyroid section:

- Ko et al. (2025/2026). Risk for Cancer With Glucagon-Like Peptide-1 Receptor Agonists... *Annals of Internal Medicine*. https://www.acpjournals.org/doi/10.7326/ANNALS-25-02237

- Clayman Thyroid Center White Paper (Feb 2026): https://www.thyroidcancer.com/blog/do-glp-1-weight-loss-shots-like-ozempic-and-mounjaro-really-raise-thyroid-cancer-risk (full PDF: https://www.thyroidcancer.com/files/GLP1s-Thyroid-Cancer.pdf)

- Vilsbøll et al. assessment of thyroid cancer risk with liraglutide/semaglutide: https://dom-pubs.onlinelibrary.wiley.com/doi/full/10.1111/dom.70291.

Related: 

• Do GLP-1 Drugs Reduce Cancer Risk? A 2026 Evidence-Based Metabolic Oncology Review
• GLP-1 Receptor Agonists May Modestly Reduce Risk of Fourteen Obesity-Related Cancers for People with Diabetes (2025 American Society of Clinical Oncology)
• GLP-1 receptor agonists and the risk for cancer: A meta-analysis of randomized controlled trials (PubMed 2025)
• Assessment of Thyroid Carcinogenic Risk and Safety Profile of GLP1-RA Semaglutide (Ozempic) Therapy for Diabetes Mellitusand Obesity: A Systematic Literature Review (2024)

Pancreatic and Other Obesity-Related Cancers: Neutral or Potentially Protective

- Pancreatic cancer: The 2025 *Annals* meta-analysis found little or no effect (moderate certainty). Some real-world data (e.g., in chronic pancreatitis patients) suggest potential reduction.

- Breast, kidney, colorectal, liver, esophageal, gallbladder, ovarian, endometrial, and others: No difference in odds vs. placebo in the 48-trial meta-analysis (low-to-moderate certainty). Subgroups (by drug, dose, population, follow-up) were consistent.

- Observational/ASCO 2026 data: Lower colon cancer risk with GLP-1 drugs (up to 36–42% relative reduction vs. aspirin in some cohorts), plus possible benefits against multiple obesity-related cancers. These likely tie to weight loss/anti-inflammatory effects rather than direct causation.

Key caveats (2025–2026 reviews):

- Most trials were not powered for cancer endpoints; median follow-up ~1–2 years is short for many cancers.

- Certainty is moderate for well-studied types and lower for rarer ones.

- No new major FDA/EMA safety signals for increased cancer risk in 2025–2026; labels retain the thyroid warning but incorporate accumulating human data.

References for pancreatic/other cancers:

- Ko et al. *Annals of Internal Medicine* meta-analysis (2025): https://www.acpjournals.org/doi/10.7326/ANNALS-25-02237 (also summarized at https://www.healio.com/news/endocrinology/20251209/glp1s-not-tied-to-increased-risk-for-obesityrelated-cancers)

- ASCO GI 2026 abstracts on GLP-1 and colorectal/pancreatic cancer risk reduction: https://ascopubs.org/doi/10.1200/JCO.2026.44.2_suppl.733 (pancreatic in chronic pancreatitis) and related CRC prevention data.

Practical Takeaways (April 2026)

The 2025–2026 evidence indicates that Ozempic/semaglutide **does not appear to raise cancer risk** in humans based on the strongest available RCT and real-world data. Earlier concerns (mostly animal or early signals) have not materialized into confirmed human risks. Potential benefits for some obesity-linked cancers warrant further study.

Recommendations:

- Contraindicated if you have personal/family history of MTC or MEN2.

- For others, cardiometabolic and weight-loss benefits generally outweigh theoretical concerns per current data.

- Discuss with your doctor, especially if you have thyroid nodules or strong family cancer history.

Ongoing long-term studies will provide more clarity. This is not medical advice—consult your healthcare provider for personalized decisions.

Additional supporting reference:

- Real-world cohort on GLP-1 and lower liver/pancreatic cancer vs. insulin: https://link.springer.com/article/10.1007/s11606-026-10300-1