If you are on a GLP-1 drug and have surgery booked, the thing to do is tell the anaesthetic team, as early as you can.
What they do with that has changed. The 2023 advice was to stop the drug before the procedure. The 2024 guidance says most patients can carry on taking it.
That reversal happened because stopping does not reliably fix the problem, not because the risk turned out to be imaginary.
Why GLP-1 drugs matter under anaesthesia
GLP-1 drugs slow how quickly the stomach empties. That is part of how they work, and our guide on fertility and pregnancy covers the other consequence of the same mechanism.
Under general anaesthesia, your airway reflexes are suppressed. If there is food or fluid still in your stomach, it can come up and go into the lungs. That is pulmonary aspiration, and it is the specific event all of this is about.
Standard fasting rules exist to prevent it: six hours without solids, two hours without clear liquids. Those rules assume a stomach that empties at a normal rate.
Does this apply to endoscopy or dental sedation?
Most people will meet this at a scope or a dentist rather than in an operating theatre, and will not think the question applies to them.
Endoscopy and colonoscopy
This is where most of the evidence actually comes from, because a camera in the stomach shows directly what is in it. Upper endoscopy under sedation raises the same question as general anaesthesia does. A colonoscopy complicates it further. The bowel preparation involves drinking a large volume of liquid, and one documented case involved a patient who had completed one and still had a full stomach.
Dental sedation
It counts too. Intravenous sedation for dental work suppresses airway reflexes in the same way, and a dental practice is less likely to ask about a weight-loss medication than a pre-operative clinic is. That makes it the setting where you are most likely to have to raise it yourself.
Local anaesthetic is different
Nothing about your airway is affected. A filling, a mole removal or a skin biopsy under local is a different situation.
The rule that covers all of it: if you will be sedated or anaesthetised to the point of being unable to protect your own airway, this applies.
Do you need to stop Ozempic before surgery?
In June 2023 the American Society of Anesthesiologists issued consensus guidance. Hold daily GLP-1 drugs on the day of the procedure. Hold weekly formulations for a week beforehand.1
That became the standard instruction, and a great many people were told it.
In 2024, multisociety clinical practice guidance revised the position. Most patients can continue GLP-1 drugs before elective procedures. For higher-risk situations, the options are a 24-hour liquid diet beforehand, gastric ultrasound where available, treating the patient as a full stomach, or deferring the procedure.2
So the advice moved from stop to assess.
Why holding the drug does not reliably work
Three pieces of evidence point the same way.
The arithmetic
Semaglutide has a half-life of roughly a week. Holding it for seven days removes about half the drug from your system. Dulaglutide is similar. A one-week pause gives you one half-life, some way short of a washout.
The data
One analysis found that interrupting semaglutide for 10 to 14 days before upper endoscopy did not predict lower residual gastric contents.3
The case
A 14-year-old who had held semaglutide for 12 days, completed a bowel preparation, fasted 32 hours from solids and 10 hours from liquids, still showed a distended stomach on ultrasound. Endoscopy confirmed more than 200 mL of residual contents.4
Twelve days, a bowel prep and a 32-hour fast, and the stomach was not empty. No clearer demonstration exists that holding the drug does not do what people take it to do.
What anaesthetic teams do now
Gastric ultrasound is the tool that changed the picture. A point-of-care scan of the stomach takes minutes, requires no preparation, and answers the question directly instead of by inference from a dosing schedule.5
Where it is available and somebody is trained to use it, the sequence is straightforward. Scan the stomach. If it is empty, proceed normally. If it is not, either delay or treat it as a full stomach and manage the airway accordingly.
Not every hospital has it or somebody proficient with it. Where it is unavailable, the alternatives are a liquid diet for 24 hours beforehand, full-stomach precautions, or postponing.
None of that is your decision to make. It is useful to know, so that a cancelled procedure reads as a reasonable precaution and not an overreaction.
What to tell the anaesthetic team
Tell them at the pre-operative assessment
Not on the day. That appointment exists to find things like this, and there is time to plan around it.
Say which drug and when you last took it
Weekly and daily formulations are handled differently, and the last dose date is the number they need.
Mention any GI symptoms
Nausea, feeling full early, reflux, or vomiting all matter here, because symptoms are part of how risk gets assessed.
Ask whether they use gastric ultrasound
Not to challenge anybody, but because the answer tells you whether they can check directly or will be working from your dosing schedule.
Do not stop on your own initiative
The advice moved away from that, and if you are taking a GLP-1 for diabetes, stopping has its own consequences.
What if your GLP-1 is not prescribed?
A lot of readers here are in this position, and it is rarely addressed.
If you are taking a GLP-1 compound bought as research material, the physiology is identical. Delayed gastric emptying does not care what was printed on the vial, and the anaesthetist needs to know regardless of where it came from.
Our guide on telling your doctor covers how to have that conversation, including the part about confidentiality. Here the calculation is simpler than usual. The alternative to speaking up is a general anaesthetic given on the assumption that your stomach is empty.
Retatrutide is worth naming separately. It is investigational and approved nowhere, so an anaesthetic team may not have encountered it. Tell them it acts like semaglutide and tirzepatide on gastric emptying, because that is the information they need to act on.
Peptides after surgery, and when to restart
The question people ask second, and it gets less attention than it deserves.
Eating enough is the recovery problem
Healing needs protein and calories, and a drug whose whole purpose is suppressing appetite works against that at exactly the wrong time. If you are back on a GLP-1 within days of surgery and eating very little, that is worth raising with whoever is managing your recovery.
BPC-157 is marketed for this directly
Post-surgical healing is one of its main selling propositions and there is no completed human trial of it for anything, which our guide to the healing pair covers. The appeal is obvious and the evidence is absent. A fresh surgical wound is a poor place to find out which matters more.
Restarting is a decision, not a default
If you held the drug for a procedure, you are in an unusual position: off it, with a clear reason, and a natural moment to decide whether to go back on. Most people restart without noticing that a choice was available. Our guide on running more than one peptide covers why open-ended protocols drift.
Whatever you decide, restart timing is a prescriber question, particularly if the drug is for diabetes.
Emergency surgery
None of the above applies in an emergency, where there is no time to assess and no option to defer.
What matters then is that somebody knows. If you are able to say what you take, say it. If you might not be able to, a note in your wallet or on your phone lock screen naming the drug does the same job.
Emergency teams manage full stomachs routinely, with a technique designed for exactly that situation. They manage it better when they know to use it.
Surgery after major weight loss
Of all the situations on this page, this one will catch the most readers, and it deserves naming rather than inference.
Large numbers of people lose 20% or more of their body weight on a GLP-1 and then have surgery for the loose skin that follows. Abdominoplasty, arm and thigh lifts, breast surgery. Elective, under general anaesthesia, often lengthy, and usually while still taking the drug.
The procedures are long, which matters because time under anaesthesia is time with a suppressed airway.
Many are done in day surgery or ambulatory settings, which are less likely to have gastric ultrasound available than a hospital theatre is.
And the drug is often still in use, because stopping it was never part of the plan. Somebody who has lost thirty kilograms is not usually looking to come off the thing that helped.
None of that argues against the surgery. It argues for the conversation happening at the consultation rather than on the morning, and for asking what the anaesthetic provider can actually do if the question arises.
What about BPC-157 and the other peptides?
Nothing comparable is established for the compounds outside the GLP-1 class.
BPC-157, the growth hormone secretagogues and the rest have no documented perioperative interactions, which reflects an absence of study and not an absence of risk. Our guide on why most peptides have no human evidence covers why that gap exists.
Anything affecting blood sugar is worth mentioning before an anaesthetic. And anything at all that you take belongs on the list you give them, because the list is how they anticipate instead of react.
Where this stops being useful
What your own team will decide, which depends on your drug, your timing, your symptoms and what their hospital can do.
Whether a specific procedure is affected, since sedation, regional and general anaesthesia carry different considerations.
Anything outside the GLP-1 class, where the evidence does not exist.
Common questions
Do I need to stop Ozempic before surgery?
The 2023 guidance said to hold weekly drugs for a week. The 2024 multisociety guidance revised that, and most patients can continue before elective procedures. Do not stop on your own, and tell the anaesthetic team at your pre-operative assessment.
Why did the advice change?
Because holding the drug did not reliably empty the stomach. One analysis found a 10 to 14 day interruption did not predict lower residual contents, and a case report documented a full stomach after 12 days off the drug and a 32-hour fast.
What is the actual risk?
Pulmonary aspiration under general anaesthesia, where stomach contents enter the lungs while airway reflexes are suppressed. Standard fasting rules assume a normally emptying stomach.
How long before surgery should I stop?
That is a question for your anaesthetic team, not a number to apply yourself. Semaglutide's half-life is about a week, so even a seven-day hold leaves roughly half the drug in place.
What if my peptide is not prescribed?
Tell them anyway. The physiology is the same whatever the label said, and a general anaesthetic given on the assumption of an empty stomach is a worse outcome than an awkward conversation.
Will they cancel my surgery?
Possibly, and it would be a reasonable precaution and not a punishment. Where gastric ultrasound is available, an empty stomach means proceeding as normal.
What about BPC-157 or growth hormone peptides?
No perioperative interactions are documented, which reflects nobody having studied it. Put them on the list anyway.
Does this apply to a colonoscopy or dental sedation?
Yes. Anything that suppresses your airway reflexes raises the same question, and most of the evidence comes from endoscopy. A procedure under local anaesthetic is a different case, since your airway keeps working normally.
Can I take BPC-157 to heal faster after surgery?
That is one of its main selling propositions and no completed human trial exists for it, for healing or for anything else. Testing something unstudied on a fresh surgical wound is a poor place to start.
When should I restart after surgery?
A prescriber question, particularly for diabetes. It is also a genuine decision point, since you are already off the drug with a clear reason, and most people restart without noticing a choice was available.
I am having surgery after losing weight on a GLP-1. Anything different?
Those procedures tend to be long, are often done in day surgery settings less likely to have gastric ultrasound, and the drug is usually still in use. Raise it at the consultation rather than on the day.
What if it is an emergency?
Emergency teams manage full stomachs routinely. What helps is them knowing. If you cannot speak, a note on your phone naming what you take does the job.
Sources
- American Society of Anesthesiologists Consensus-Based Guidance on Preoperative Management of Patients on GLP-1 Receptor Agonists, June 2023. The guidance recommended withholding daily-dosed GLP-1 receptor agonists on the day of an elective procedure and weekly-dosed formulations one week beforehand. ↩
- Kindel TL, et al. Multisociety clinical practice guidance for the safe use of glucagon-like peptide-1 receptor agonists in the perioperative period. *Anesthesiology*. 2024. The guidance advises that most patients can continue GLP-1 receptor agonists before elective procedures, with risk-reduction measures for higher-risk patients. ↩
- Silveira SQ, et al. Relationship between perioperative semaglutide use and residual gastric content: A retrospective analysis of patients undergoing elective upper endoscopy. *Journal of Clinical Anesthesia*. 2023;87:111091. ↩
- Unanticipated Residual Gastric Contents in an Appropriately Fasted Pediatric Patient on Glucagon-Like Peptide-1 Receptor Agonist Therapy. Peer-reviewed case report. A single case illustrates why holding intervals can be unreliable; it does not establish how frequently this occurs. ↩
- Role of Gastric Point-of-Care Ultrasound in Perioperative Management of Semaglutide. Prospective pilot study of pre-operative gastric ultrasound in patients taking semaglutide. ↩