GLP-1 medicines and your gut
General education about how glucagon-like peptide-1 (GLP-1) medicines — such as Ozempic, Wegovy, Mounjaro and Saxenda — interact with your gut. Not medical advice: never start, stop or change these medicines without talking to your prescriber.
Why these medicines affect your gut
Glucagon-like peptide-1 (GLP-1) medicines work partly by slowing how quickly the stomach empties and by acting on appetite signals. That's part of how they help — and it's also why the gut feels them most.
Common gut effects include nausea, reflux, burping, constipation, feeling full very quickly, and sometimes loose stools. These are usually most noticeable when starting the medicine or moving up a dose, and often settle as your body adjusts. If they don't settle, that's a conversation for your prescriber — dose pacing can often be adjusted.
Gentle habits many people find helpful
These are general comfort habits, not treatment:
- Smaller meals, eaten slowly. A slower stomach copes better with less at a time.
- Stop when comfortably satisfied rather than full — fullness arrives late when emptying is slow.
- Go easy on rich, fatty or very large meals, which sit longest in the stomach.
- Stay upright for a while after eating if reflux bothers you.
- Sip fluids through the day, and for constipation, build fibre up gradually alongside fluids and gentle movement.
- Keep your nutrition quality up. With a smaller appetite, what you do eat matters more — regular meals with protein, fibre and variety. If eating starts to feel stressful or hard, tell your doctor.
Before a procedure — tell your care team
Tell the procedure team that you use a GLP-1 medicine. Your procedure team will tell you exactly what to do with the medicine.
For Colonoscopy Brisbane, skip breakfast on the day before your procedure. Then follow the exact instructions in your bowel preparation sheet and confirmation letter, including any modified fasting plan. Never stop it without specific instruction. If it is used for diabetes, only change it with specific advice from your GP, endocrinologist or procedure team.
When to talk to your doctor
See your doctor promptly if you have severe or persistent vomiting, can't keep fluids down, show signs of dehydration, or have severe or persistent tummy pain — these need assessment rather than self-management. Ongoing reflux, constipation or nausea that isn't settling is also worth raising with your prescriber rather than pushing through.
This page is general education to support — never replace — the advice of your prescriber and care team.
One question to take with you
Does your care team know which medicine you take, and do you know whose instructions to follow before a procedure?
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General gut-health education from your care team. It doesn't replace advice from your doctor or an Accredited Practising Dietitian — please talk to them about your own situation.