Wegovy side effects: what’s common, what’s normal, and when to get help
Most Wegovy side effects are gastrointestinal and tend to be most noticeable when you start or increase the dose. Many settle as your body adjusts, but it’s important to know what’s normal and what needs medical advice.
Common Wegovy side effects (many people get one or more)
- Nausea
- Diarrhoea
- Constipation
- Vomiting
- Stomach pain or cramps
- Indigestion/heartburn (acid reflux)
- Feeling bloated or gassy / burping
- Reduced appetite
- Headache
- Tiredness or fatigue
Less common side effects
- Dizziness
- Injection-site reactions (redness, tenderness, itching)
- Changes in taste or feeling “off food”
- Mild low mood or irritability (often linked to reduced intake/feeling unwell)
Good to know: Side effects are often worse if you eat large, fatty or very rich meals, eat quickly, or don’t drink enough fluids.
When to contact a doctor urgently
Seek urgent medical advice the same day if you have any of the following:
- Severe or persistent stomach/upper abdominal pain, especially if it spreads to your back or is accompanied by vomiting
- Signs of dehydration (very dark urine, dizziness, fainting, not peeing much)
- Repeated vomiting that you can’t keep fluids down
- Severe allergic reaction (swelling of face/lips/tongue, breathing difficulty, widespread rash)
- Yellowing of the skin/eyes, fever, or severe right-sided upper abdominal pain (possible gallbladder issue)
If symptoms are worrying but not an emergency, contact your GP/pharmacist for advice.
Quick overview: side effects by dose stage
| Dose stage | What you might notice | Practical tips that often help |
|---|---|---|
| Weeks 1–4 (starting dose) | Nausea, reduced appetite, mild heartburn, constipation or diarrhoea | Smaller meals, eat slowly, avoid greasy/spicy foods, sip fluids through the day |
| After a dose increase | A short “bump” in nausea/reflux/burping, or looser stools/constipation | Keep meals plain, prioritise protein, add fibre gradually, consider smaller portions for a few days |
| Higher doses (later weeks) | Some people feel fine; others get intermittent nausea/constipation | Don’t skip meals then overeat; keep hydration consistent; manage constipation early |
Tip: If side effects flare after increasing your dose, keep your routine simple for a few days (bland foods, smaller portions, steady fluids).
How to get prescribed Wegovy with an online doctor
Step 1: complete a short medical questionnaire with an online doctor in Ireland, such as Zava.
Step 2: if a weight loss medicine is appropriate, a prescription is issued and sent to your chosen pharmacy via Healthmail. If you choose Healthwave, the prescription can be addressed to healthwave.dundrum@healthmail.ie.
Step 3: the pharmacy confirms availability, explains pen use and storage. If you choose Healthwave, we pack discreetly and deliver typically within 1–2 working days, or arrange convenient collection.
Prefer to speak directly with a doctor?
Easily book a video consultation with a registered doctor via Eirdoc.
Prefer to see a doctor in person?
First 4 weeks on Wegovy 0.25 mg: settling in and nausea management
The starting dose is usually 0.25 mg once weekly. Nausea, fullness, burping, mild diarrhoea or constipation can occur as your body adapts. Eat slowly, stop before you feel very full and keep water intake steady. Many people find smaller, simple meals more comfortable.
If symptoms are uncomfortable, speak to a pharmacist about over-the-counter options for reflux or constipation. If vomiting or dehydration occurs, contact a doctor for advice.
To ensure you are storing your Wegovy pens correctly, read our guide on storing GLP-1 weight loss drugs.
Weeks 5 to 8 on 0.5 mg: reflux, constipation and practical food choices
As the dose rises, reflux or constipation may appear. Choose gentle meals such as soup, yoghurt, eggs, beans, fish or chicken with vegetables. Limit fried foods and high fat meals, avoid large portions of red meat and pace meals through the day.
Keep activity gentle, for example short walks. If you take medicines that can irritate the stomach, take them with food if allowed and ask a pharmacist if spacing them from your injection helps.
Weeks 9 to 12 on 1.0 mg: listening to appetite and dose pacing
Appetite often reduces further. Focus on protein, fibre and fluids rather than chasing very low calories. If nausea returns with each increase, ask your doctor whether to pause at the current dose for longer before moving up.
If you experience persistent tummy pain, black stools or repeated vomiting, stop the medicine and seek urgent care.
Weeks 13 to 20 on 1.7 mg to 2.4 mg: maintenance and reducing flare ups
Many people move to 1.7 mg then 2.4 mg as a maintenance dose if tolerated. Side effects often settle once the dose is stable. Keep meals light, avoid heavy late evening meals and limit alcohol while you adjust.
Plan reviews with your doctor to check comfort, weight trend, blood tests if needed and any other medicines that may need dose changes due to appetite or absorption changes.
Practical tips that reduce side effects on Wegovy
- Eat slowly and stop early if you feel very full.
- Favour lean protein, vegetables, beans and whole grains, and keep water intake steady.
- Keep a symptom note so you can share patterns at reviews.
- Rest and choose light foods if you feel unwell. Seek medical advice if symptoms are severe or persistent.
When to contact a doctor during treatment
Seek urgent medical advice if you have severe tummy pain that does not settle, repeated vomiting, signs of dehydration or black stools. Discuss any planned surgery or deep sedation with your doctor due to delayed stomach emptying on GLP-1 treatment.
Supports available in Ireland
FAQs
How long do Wegovy side effects last?
Most effects settle within a few days to weeks at each dose. If symptoms are severe or continue, contact a doctor to review dose pacing or supportive treatment.
Can I drink alcohol while taking Wegovy?
Alcohol can worsen reflux and nausea. If you choose to drink, keep amounts small and avoid drinking near your injection day while you adjust.
What foods are easiest when I feel nauseous?
Try light choices such as soup, yoghurt, porridge, crackers, bananas or eggs. Avoid very rich or spicy meals until you are comfortable again.
Do I need blood tests while on Wegovy?
Your doctor will advise based on your health background. Reviews focus on comfort, weight trend and any other medicines that might need adjustment.
What are the most common Wegovy side effects?
The most common side effects are stomach-related: nausea, diarrhoea, constipation, vomiting, indigestion/heartburn, bloating and stomach pain. Headache and tiredness can also happen, especially early on.
Wegovy 0.25mg side effects: what’s normal in the first month?
The 0.25mg starting dose is mainly to help your body adjust. It’s common to notice reduced appetite and mild nausea or digestive changes (constipation or looser stools). For many people, symptoms improve as the weeks go on.
Do Wegovy side effects get worse when you increase the dose?
They can. A dose increase often causes a short-term flare of nausea, reflux/burping, constipation or diarrhoea. For many people, this settles within days to a couple of weeks as they adjust to the new dose.
When do Wegovy side effects usually start?
Some people notice symptoms after the first injection; others only notice changes after the first dose increase. Side effects are usually most noticeable in the first few weeks of a new dose.
What helps with nausea on Wegovy?
Many people find it helps to eat smaller meals, avoid fatty/greasy foods, eat slowly, and keep hydrated by sipping fluids regularly. Plain foods can be easier during “nausea days”.
When should I stop Wegovy and seek urgent help?
Get urgent medical advice if you have severe/persistent abdominal pain, repeated vomiting with inability to keep fluids down, signs of dehydration, an allergic reaction, or symptoms that feel severe or unusual for you.
If you would like to explore whether treatment is suitable, you can fill in a quick questionaire with our online doctor partner Zava.
For more information and to view our prices see Wegovy. Need pharmacist advice today? Ask a Pharmacist.
