Starting a GLP-1 weight loss pen is a huge step in your journey โ congratulations! These pens can make it much easier to manage hunger, but like all medications, they can sometimes cause side effects.
๐ The good news? Not everyone experiences them, and most are temporary as your body adjusts.
๐ The most common side effects involve the stomach and digestive system.
๐ They may come back when your dose increases but usually improve again with time.
Hereโs a practical guide to the most common GLP-1 pen side effects and how to manage them like a pro.
Managing Nausea and Vomiting on GLP-1 Pens
Nausea is the most common side effect when starting Saxenda, Wegovy, or other GLP-1 medications.
How to manage nausea
- Eat smaller, more frequent meals instead of large ones.
- Slow down and eat mindfully (avoid distractions).
- Stick to low-fat, bland foods like toast, rice, eggs, or broth.
- Stay upright after eating โ avoid lying down.
- Ginger tea, ginger biscuits, or peppermint may ease nausea.
- If nausea is severe โ speak to your provider about dose changes or temporary medication (e.g., cyclizine 50mg).
How to Reduce Diarrhoea from GLP-1 Injections
Diarrhoea is another common digestive side effect.
What helps:
- Stay hydrated with water, broths, or electrolyte drinks.
- Use oral rehydration sachets (200โ400ml after each loose stool).
- Consider loperamide: 2 capsules first, then 1 after each loose stool (max 8/day).
- Avoid greasy, spicy, or high-fibre foods.
- Small, light meals are best until it settles.
GLP-1 Pen Constipation Relief Tips
Some people experience the opposite โ constipation.
How to prevent and treat constipation:
- Slowly increase fibre (fruits, vegetables, oats, psyllium husk).
- Try Fybogel sachets (1 twice daily).
- Use Laxido (1โ3 sachets daily for up to 2 weeks, then 1โ2 daily for maintenance).
- Drink 6โ8 glasses of water/day.
- Light walking (10โ15 minutes, twice daily) helps your gut move.
- Short-term aids: Senna, DulcoEase, or glycerin suppositories.
Indigestion While Using GLP-1 Injections
Some people experience heartburn or indigestion.
Relief options:
- Antacids (e.g., Gaviscon).
- H2 blockers (e.g., Zantac 75).
- Proton Pump Inhibitors (e.g., Nexium) if heartburn is also present.
How to Reduce Burping
Burping can be annoying but manageable.
Tips:
- Eat and drink more slowly.
- Avoid fizzy drinks.
- Skip chewing gum.
- A short walk after eating may help.
- Avoid fatty foods
GLP-1 Injection Site Reactions: What to Do
Up to 1 in 10 people may get soreness, redness, itching, or bruising where they inject.
What helps:
- Usually improves as your body adjusts.
- Try a non-drowsy antihistamine (loratadine, cetirizine, or fexofenadine).
- If itching affects sleep โ a sedating antihistamine like chlorphenamine may help.
GLP-1 Pen Headaches Explained
Headaches are usually mild.
What helps:
- Drink more water (dehydration is a common cause).
- Take paracetamol if needed.
Other Common GLP-1 Side Effects
Some users report:
- Changes in taste
- Dizziness
- Gallstones
- Low blood sugar (hypoglycaemia)
Low blood sugar warning signs: sweating, pale skin, headache, fast heartbeat, nausea, hunger, blurred vision, sleepiness, weakness, anxiety, confusion, shaking.
What to do:
- Eat/drink fast-acting carbs like a banana, juice, or regular (not diet) soda.
Serious Side Effect: Pancreatitis and GLP-1 Pens
Though uncommon, GLP-1 pens (like Saxenda, Mounjaro and Wegovy) may cause pancreatitis (inflammation of the pancreas).
๐จ Seek urgent medical help and stop your pen if you experience:
- Severe, persistent stomach pain (may spread to your back)
- Nausea and vomiting
This can be life-threatening if untreated.
FAQ: GLP-1 Pen Side Effects
1. Do GLP-1 pens always cause side effects?
No. Many people tolerate them well. Side effects are most common at the start or when increasing the dose.
2. How long do GLP-1 side effects last?
Most side effects improve within a few days to weeks as your body adjusts. They may return temporarily when your dose increases.
3. Can I prevent nausea on a GLP-1 pen?
Yes โ eat smaller meals, avoid high-fat foods, eat slowly, and stay upright after meals.
4. When should I call my doctor about side effects?
If nausea, diarrhoea, or constipation are severe or persistent, or if you experience severe stomach pain, vomiting, or signs of pancreatitis, seek medical advice immediately.
5. Do GLP-1 pens cause long-term side effects?
Most side effects are temporary. Rare but serious risks include pancreatitis or gallstones, which require medical attention.
Final Thoughts on GLP-1 Pen Side Effects
Although you may have experienced some side effects you've taken an important step towards better health. Yes, there might be some bumps along the way, but you're not alone in this journey. With the right knowledge and support, you can manage these side effects and focus on your goals.
Remember to be kind to yourself. Celebrate your progress, no matter how small. You're doing something great for your health, and that's worth celebrating.
Bibliography
1) UK Government. (2024, October 24). GLP-1 receptor agonists: Reminder of the potential side-effects and to be aware of the potential for misuse. Medicines and Healthcare products Regulatory Agency. https://www.gov.uk/drug-safety-update/glp-1-receptor-agonists-reminder-of-the-potential-side-effects-and-to-be-aware-of-the-potential-for-misuse GOV.UK
2) Collins, L., & Costello, R. A. (2024, February 29). Glucagon-Like Peptide-1 Receptor Agonists. In StatPearls [Internet]. StatPearls Publishing. https://www.ncbi.nlm.nih.gov/books/NBK551568/
Author: Margaret Hudson MRPharmS