Wegovy Side Effects & Management UK 2026

Wegovy is a once-weekly injection containing semaglutide (a GLP-1 medicine). Side effects are most commonly gastrointestinal (nausea, diarrhoea, vomiting, constipation) and are usually strongest during the dose-escalation phase. The good news: for most people, symptoms reduce as the body adapts—especially with the right strategy.

🛠️ Side Effects Counter Toolkit (Do This Before You Feel Rough)

Most Wegovy discomfort is predictable and preventable. Use this “toolkit” from week 1, and re-use it for 3–7 days after each dose increase.

1) The 48-Hour Food Plan (works for nausea, reflux, bloating)

• Portion halve: Eat ~50% of your normal portion size for 48 hours after injecting.
• Low-fat, low-spice: Avoid greasy foods, creamy sauces, fried foods, and chilli.
• Protein first: Aim for a protein anchor at each meal (e.g., eggs, chicken, fish, Greek yoghurt, tofu).
• Gentle carbs: Oats, rice, toast, bananas, potatoes help settle the stomach.
• Stop at “comfortable”, not “full”: Overfilling is the fastest route to nausea/vomiting.

2) Hydration & Electrolytes (prevents headaches, dizziness, kidney issues)

• Small sips all day: instead of big glasses (which can trigger nausea).
• Electrolytes if needed: if diarrhoea/vomiting hits, use oral rehydration salts or an electrolyte drink.
• Urine check: if urine is dark and you’re dizzy, treat as dehydration and escalate care if it persists.

3) Constipation Prevention (start this on day 1)

• Daily fibre “baseline”: one fibre habit per day (oats, chia, berries, veg soup).
• Water + movement: a 10–20 min walk after meals helps bowel motility.
• Add soluble fibre: psyllium husk can help (start low and increase gradually).
• If no bowel movement for 3+ days: speak to a pharmacist/GP about an appropriate laxative plan.

4) Reflux / Heartburn Fixes

• Don’t lie down after eating: stay upright for 2–3 hours.
• Earlier last meal: finish dinner 3+ hours before bed.
• Trigger audit: common triggers include fatty food, chocolate, peppermint, alcohol, fizzy drinks.
• OTC options: alginates/antacids may help—ask a pharmacist what’s suitable for you.

5) The “Dose Increase Buffer” (how to reduce side effects massively)

• Expect a temporary flare: symptoms often reappear for a few days after each step up.
• It’s normal to go slower: your prescriber can keep you on a dose longer if you need more time to adapt.
• Don’t jump doses: follow the prescribed schedule (commonly 0.25 → 0.5 → 1.0 → 1.7 → 2.4 mg).

🔵 Common Wegovy Side Effects

In trials, the most frequent side effects were gastrointestinal—especially during dose escalation. Reported rates included nausea (~44%), diarrhoea (~31%), vomiting (~24%) and constipation (~24%). These were usually mild–moderate.

1) Nausea

• Most likely: first weeks and 1–3 days after dose increases.
• Best fixes: smaller meals, lower fat, slow eating, ginger/peppermint, cool foods, hydration in small sips.
• Ask for help if: nausea stops you eating/drinking for 24+ hours.

2) Diarrhoea

• Best fixes: hydration + electrolytes, bland foods short-term, reduce high-fat foods and alcohol.
• Seek advice if: severe diarrhoea lasts 24+ hours, or you show dehydration signs.

3) Constipation

• Best fixes: soluble fibre, daily walking, water, prunes/kiwi, pharmacist plan if persistent.
• Seek advice if: no bowel movement for 3+ days with pain/bloating.

4) Vomiting

• Best fixes: pause solid foods, clear fluids, reintroduce bland foods slowly.
• Urgent if: you can’t keep fluids down for 12+ hours.

5) Abdominal discomfort / bloating

• Best fixes: smaller portions, avoid fizzy drinks and heavy/fatty meals, walk after eating.
• Urgent if: severe persistent pain, especially radiating to the back.

🟡 Less Common (But Still Seen)

• Fatigue: often from low intake—prioritise protein, fluids, and steady sleep.
• Headache/dizziness: frequently dehydration-related—use the hydration protocol above.
• Injection-site reactions: mild redness/itching—rotate sites and inject at room temperature.
• Hair shedding: usually rapid weight loss (telogen effluvium)—adequate protein helps.
• Gallstones: risk rises with faster weight loss—know the warning signs below.

🔴 Rare But Serious: Know These Red Flags

Possible pancreatitis

• Severe, persistent upper abdominal pain (may radiate to the back), often with vomiting and feeling very unwell.

Severe dehydration / kidney strain

• Very little urine, dark urine, dizziness/fainting, rapid heartbeat—especially after vomiting/diarrhoea.

Gallbladder problems

• Upper right abdominal pain (often after fatty meals), fever, yellowing skin/eyes—needs same-day assessment.

Serious allergic reaction

• Swelling of face/throat, breathing difficulty, widespread hives—call emergency services.

Sudden vision changes

• Sudden vision loss or significant vision change needs urgent assessment.

⏰ Side Effect Timeline (What Most People Experience)

❌ Missed Dose: What To Do

• If you missed a dose and it’s within 5 days: take it as soon as possible, then continue on your usual injection day.
• If more than 5 days have passed: skip the missed dose and take the next one on your regular day.
• Never take two doses close together to “catch up”.

🎯 Key Takeaways

• GI effects are common: nausea/diarrhoea/vomiting/constipation are the main ones.
• Most improve over time: especially after dose escalation ends.
• The toolkit matters: smaller, lower-fat meals + hydration + constipation prevention solves most problems.
• Go slower if needed: ask your prescriber about staying at a dose longer if symptoms are disruptive.
• Know red flags: severe abdominal pain, dehydration signs, allergic reaction, sudden vision change.