Key takeaways
- Nausea, constipation, diarrhoea and tiredness are the most common GLP-1 side effects, especially after starting or increasing a dose.
- For many people they ease within a few days of each dose and settle over the first weeks.
- Small, slow, protein-first meals and steady water intake often help.
- Severe or lasting symptoms need medical advice. Never change your dose without your prescriber.
Why side effects happen
GLP-1 medicines slow how quickly your stomach empties and turn down appetite signals. That’s part of how they work, and it’s also why your stomach can feel unsettled while your body adjusts, especially in the days after a dose or a step up.
The most common side effects
Side effects vary from person to person. These are the ones people mention most often, with simple ideas that many find helpful:
| Side effect | How often | What often helps |
|---|---|---|
| Nausea | Very common | Smaller meals, eat slowly, stop when you’re just full, sip water |
| Constipation | Common | Water, fibre from veg and oats, gentle daily movement |
| Diarrhoea | Common | Fluids and simple foods; avoid very fatty meals |
| Tiredness | Common | Regular meals with protein, steady sleep, light activity |
| Reflux or burping | Common | Avoid lying down after meals; smaller evening portions |
What many people find helpful
- Eat smaller meals and stop when you feel just full.
- Start meals with protein, then vegetables. Our protein calculator gives you a daily target.
- Sip water through the day rather than drinking a lot at once.
- Keep very rich, greasy or spicy meals for later in your journey.
- Note how you feel each day so you can see your pattern.
When to get urgent help
- Severe stomach pain that doesn’t go away, sometimes spreading to your back
- Vomiting that stops you keeping fluids down, or signs of dehydration
- Yellowing skin or eyes, or pain in the upper right of your tummy
- Swelling of the face or throat, or difficulty breathing
In the US, call your prescriber, or 911 in an emergency. In the UK, call NHS 111, or 999 in an emergency.
Tracking your pattern
Logging a two-second check-in after each dose builds a simple picture of when symptoms peak and ease. Bringing that to your appointment makes it easier to decide on next steps together with your prescriber.
Panda’s side-effect tracker turns these check-ins into a heat map and a PDF you can share.
Sources
- NHS: Semaglutide medicine guide (side effects)
- MedlinePlus: Semaglutide injection
- US FDA prescribing information for Ozempic®, Wegovy®, Mounjaro® and Zepbound® (via DailyMed)
- MHRA and EMA product information for Wegovy® and Mounjaro®
This guide is general information, not medical advice, and doesn’t replace a conversation with your prescriber, pharmacist or doctor. Panda never suggests, calculates or changes a dose.
