GLP-1 Before a Colonoscopy: Stop It or Not?

If you take Ozempic, Wegovy, Mounjaro, Zepbound or any other GLP-1 and you have a colonoscopy or upper endoscopy coming up, the question you're searching is simple: do I stop it first, and for how long? The honest answer is that the experts disagreed, and the safest move is to not decide this on your own. GLP-1 drugs slow gastric emptying, so your stomach can still hold food and fluid after standard fasting — which raised concern about regurgitation and aspiration under sedation. In a pooled analysis of 23 studies and 262,018 patients, GLP-1 users were about 4.5× more likely to have retained gastric contents at endoscopy and more likely to have the procedure stopped early — but the rate of aspiration pneumonia was not significantly increased (Baig 2025 ^[1]). In June 2023 the American Society of Anesthesiologists (ASA) told patients to hold the drug; gastroenterology and bariatric groups pushed back that blanket holding may be unnecessary and an individualized plan is reasonable (Hashash 2024 ^[2]). This article walks through that disagreement and what it means for your prep. For the general surgery/anesthesia version, see holding a GLP-1 before surgery.

The honest summary

• The concern is real but specific. Slowed gastric emptying means retained food/fluid in the stomach. At upper endoscopy, GLP-1 users had roughly 4.5× the odds of retained gastric contents and of needing the procedure aborted — but pooled data did not show more aspiration pneumonia (Baig 2025^[1]).
• ASA said hold it (June 2023). The anesthesiologists' consensus advised stopping daily-dosed GLP-1s on the day of the procedure and weekly-dosed ones (Ozempic, Wegovy, Mounjaro, Zepbound) about a week before (Hashash 2024^[2]).
• GI societies pushed back. The AGA's rapid update argued for an individualized approach — based on why you take it, whether you have symptoms, how long you'll fast, and how urgent the test is — rather than reflexively cancelling procedures (Hashash 2024^[2]).
• The 2024 multisociety consensus split the difference. It favored shared decision-making plus a clear-liquid diet for at least 24 hours before — the same kind of prep colonoscopy already uses — and saving a strict hold for higher-risk situations (Kindel 2024^[3]).
• A one-week hold may not even empty the stomach. In one study, holding semaglutide for under 8 days still left a 10-fold higher chance of retained contents; only stopping >14 days (no symptoms) reliably normalized it (Santos 2024^[4]).
• Bottom line: don't stop on your own. Protocols differ by center. Coordinate with the prescriber and the endoscopy unit, and follow your facility's instructions.

Why a colonoscopy or endoscopy raises the question

GLP-1 receptor agonists slow how fast the stomach empties — that delayed emptying is part of how they curb appetite. The downside is that your stomach can still contain solids or fluid even after you've followed the usual “nothing to eat” fasting window. Colonoscopies and upper endoscopies are almost always done under sedation or anesthesia, and a stomach that isn't empty creates a theoretical risk of regurgitating and aspirating contents into the lungs. The first hard signal came from Silveira 2023^[5], a retrospective study of 404 patients having upper endoscopy: those who'd taken semaglutide within 30 days had retained gastric contents 24.2% of the time versus 5.1% of non-users, an adjusted odds ratio of about 5.2 — even though most had stopped the drug roughly 10 days before. A prospective gastric-ultrasound study in volunteers found the same direction of effect (Sherwin 2023^[6]).

Those single-center findings have since been pooled. Baig 2025^[1] combined 23 studies and 262,018 patients and found GLP-1 users had about 4.5× the odds of retained gastric contents (OR 4.54) and 4.5× the odds of having the endoscopy terminated early — but, importantly, no significant increase in aspiration pneumonia (OR 0.96). In other words, the “food in the stomach” finding is robust; the leap from that to actual lung injury is not well supported by the outcome data so far. That gap is exactly why the specialties disagreed about how aggressively to hold the drug.

What the ASA said vs. what the GI societies said

In June 2023 the American Society of Anesthesiologists issued consensus-based guidance recommending that patients hold their GLP-1 before elective procedures: skip the dose on the day of the procedure for daily-dosed agents, and stop weekly-dosed agents (semaglutide as Ozempic/Wegovy, tirzepatide as Mounjaro/Zepbound) about a week beforehand. In practice this led some anesthesia teams to cancel or postpone endoscopies when patients hadn't held the drug (Hashash 2024^[2]).

Gastroenterologists pushed back. The American Gastroenterological Association's rapid clinical practice update (Hashash 2024^[2], Clinical Gastroenterology & Hepatology) argued for an individualized approach rather than blanket discontinuation — weighing why you take the drug, whether you have ongoing GI symptoms, how long you'll have fasted, and whether the procedure is urgent. Their reasoning: stopping a GLP-1 in someone with diabetes can worsen blood-sugar control (which itself harms outcomes), holding a single weekly dose may not reliably restore normal stomach emptying anyway, and cancelling needed cancer-screening or diagnostic procedures carries its own risk. The disagreement wasn't about whether the stomach can be fuller — it was about whether reflexively holding the drug actually fixes the problem and is worth the trade-offs.

The 2024 multisociety guidance — written jointly by anesthesiology, gastroenterology, and bariatric-surgery groups — tried to reconcile the two camps (Kindel 2024^[3]). It recommended that perioperative GLP-1 decisions be based on shared decision-making balancing the need for the drug against individual aspiration risk, and offered a middle path: for patients where delayed emptying is a concern, a clear-liquid diet for at least 24 hours before the procedure — “as performed in patients undergoing colonoscopy and bariatric surgery” — instead of, or in addition to, holding the drug. For higher-risk cases it suggested options like point-of-care gastric ultrasound on the day, treating the patient as “full stomach” with a rapid-sequence anesthesia technique, or, rarely, rescheduling. It still acknowledged the original ASA hold timing as a reasonable option when a hold is chosen.

What this means for your prep — the practical upshot

• Don't stop your GLP-1 on your own. The right plan depends on the drug, your dose schedule, why you take it, and your facility's protocol — which vary between centers. Self-discontinuing can also worsen diabetes control.
• Tell BOTH your anesthesiologist/endoscopy unit AND your prescriber, well ahead. Mention the exact drug (Ozempic, Wegovy, Mounjaro, Zepbound, Rybelsus, etc.), your dose, and when you last took it. Ask specifically: should I hold a dose, and should I extend my clear-liquid diet?
• Expect a possible extended clear-liquid diet. Many centers now ask GLP-1 users to do at least 24 hours of clear liquids before the procedure (Kindel 2024^[3]) — and for colonoscopy that's already part of bowel prep.
• Flag any ongoing GI symptoms. Nausea, vomiting, bloating, or feeling full are the strongest predictors of retained stomach contents (Silveira 2023^[5]; Santos 2024^[4]). If you have them near your procedure date, say so — it may change the plan.
• Follow YOUR facility's written instructions. Protocols genuinely differ; the consensus documents leave room for local judgment. Your endoscopy unit's sheet is the one that counts.

Bowel prep + a GLP-1: a dehydration warning

There's a second, often-overlooked concern that's specific to colonoscopy. Bowel prep itself causes large fluid losses, and GLP-1 drugs can cause nausea and vomiting. If a GLP-1's GI side effects make it hard to keep the prep solution and clear liquids down, the combination can compound dehydration — and GLP-1 medications have been associated with acute kidney injury in the setting of severe vomiting and volume depletion. The takeaway isn't to panic; it's to take hydration seriously during prep, and to tell your team promptly if vomiting is keeping you from finishing the prep or staying hydrated. For more on this side-effect profile, see common GLP-1 side-effect questions answered.

Bottom line

GLP-1 drugs do leave more food in the stomach at endoscopy — about 4.5× the odds in pooled data — but that has not translated into more aspiration pneumonia in the evidence so far (Baig 2025^[1]). The ASA initially said hold the drug; gastroenterology and bariatric societies argued for individualized assessment and a clear-liquid prep instead of reflexive cancellation (Hashash 2024^[2]; Kindel 2024^[3]), and a strict one-week hold may not even empty the stomach reliably (Santos 2024^[4]). Because the protocols genuinely differ by center, the single safest thing you can do is not decide alone: tell both your prescriber and the endoscopy unit which GLP-1 you take and when you last took it, ask about holding a dose and extending clear liquids, and follow your facility's written instructions.

This article is educational and is not medical advice. Every claim above is sourced to a peer-reviewed study, society clinical practice update, or multisociety consensus indexed in PubMed, verified against the live PubMed database (and, for the consensus wording, the open-access fulltext) before publication. Coordinate your own pre-procedure plan with your prescriber and endoscopy team.