GLP-1 receptor agonists commonly cause gastrointestinal side effects by slowing gut motility, and current management strategies for these effects lack strong evidence-based support.
1987–2025 literature spanA comprehensive review covering nearly four decades of research on GLP-1 physiology and the gastrointestinal effects of GLP-1 receptor agonists.
What the researchers found
GLP-1 receptor agonists affect gastrointestinal function primarily by slowing gastric emptying and gut transit, which directly contributes to their most common adverse events including nausea, vomiting, and gastroparesis-like symptoms.
A key safety concern highlighted is gastric food retention caused by GLP-1RAs, which increases the risk of pulmonary aspiration during procedures requiring anesthesia. This has prompted changes to pre-anesthesia guidelines for patients taking these medications.
The review also identifies associations between GLP-1RA use and extraintestinal complications including biliary tract disease and pancreatitis. Importantly, current management recommendations — including dosing adjustments, dietary modifications, and pharmacotherapy for GI symptoms — are described as empiric rather than evidence-based.
Why it matters
With millions of people now taking GLP-1 receptor agonists for weight loss and diabetes, understanding the gastrointestinal consequences is critical for both patients and clinicians. The finding that current management strategies lack evidence-based support highlights a significant gap in care, and the aspiration risk during anesthesia has direct implications for surgical safety protocols.
How the study worked
The authors conducted a comprehensive literature search of PubMed and EMBASE databases covering publications from July 1987 through August 2025. They synthesized findings on GLP-1 physiology, GLP-1RA effects on GI transit and motility, associated symptoms, and management approaches into a narrative review.
What this study cannot tell us
This is a narrative review, not a systematic review or meta-analysis, so the literature search may not be exhaustive. The review does not quantify the incidence rates of specific GI adverse events across different GLP-1RAs. Management recommendations are acknowledged by the authors themselves as lacking evidence-based support, meaning the guidance offered is largely expert opinion.
How to read the evidence
This is a narrative review synthesizing existing literature from two major databases. While comprehensive in scope and published in an expert review journal, it does not employ systematic review methodology or meta-analysis.
When this study was published
Published in 2025 with literature searched through August 2025, this is a highly current review that captures the latest evidence on GLP-1RA gastrointestinal effects during peak adoption of these drugs.
The bigger picture
As GLP-1 receptor agonists become some of the most prescribed medications globally, this review underscores that the rush of adoption has outpaced our understanding of their GI effects. The call for multicenter prospective studies to develop evidence-based management protocols reflects a broader challenge in pharmacology: managing side effects of blockbuster drugs often relies more on clinical intuition than rigorous data. New dual- and triple-agonist drugs in development may carry similar or additional GI risks.
Questions still open
- How do the GI side effect profiles differ meaningfully between specific GLP-1RA drugs like semaglutide, liraglutide, and tirzepatide?
- What pre-anesthesia fasting protocols should be standard for patients on GLP-1 receptor agonists to minimize aspiration risk?
- Will newer multi-agonist incretin drugs have better or worse GI tolerability compared to current GLP-1RAs?
Common questions
Why do GLP-1 weight loss drugs cause nausea and stomach problems?
Is it safe to have surgery while taking a GLP-1 receptor agonist?
Read the original research
Impact of GLP-1 receptor agonists on gastrointestinal function and symptoms.
Expert review of gastroenterology & hepatology, 19(11), 1181-1195
Citation
Frazier, Rosita D; Hasler, William L. (2025). Impact of GLP-1 receptor agonists on gastrointestinal function and symptoms.. Expert review of gastroenterology & hepatology, 19(11), 1181-1195. https://doi.org/10.1080/17474124.2025.2579117