Wegovy side effects: week-by-week

Most side effects occur during dose escalation (the first 16 weeks) and improve as your body adjusts. Here's what to expect at each stage.

Phase	Dose	Common side effects	What to do
Weeks 1–4	0.25mg	Mild nausea, reduced appetite	Eat smaller meals. Stay hydrated. Take it slow.
Weeks 5–8	0.5mg	Nausea may increase temporarily, fatigue	Avoid fatty/heavy meals. Ginger tea can help nausea.
Weeks 9–12	1.0mg	Nausea, constipation or diarrhoea, headache	If nausea is severe, your doctor may extend this dose before increasing.
Weeks 13–16	1.7mg	GI symptoms may peak then start improving	This is typically the hardest phase. It does get better.
Week 17+	2.4mg	Most GI side effects have settled. Possible constipation.	Maintain hydration, fibre intake. Report any new symptoms.

Most common side effects

In clinical trials, the most frequently reported side effects of Wegovy were:

Nausea — affects up to 44% of users, mostly during escalation. Usually mild-to-moderate.
Diarrhoea — affects around 30%. Typically resolves within a few weeks.
Vomiting — affects around 24%. More common at higher doses.
Constipation — affects around 24%. Can persist at maintenance dose.
Abdominal pain — affects around 20%. Usually related to eating speed or portion size.
Headache — affects around 14%. Typically resolves early.

Tips for managing side effects

Eat smaller, more frequent meals instead of large portions
Avoid high-fat and very rich foods, especially during escalation
Stay well hydrated — sip water throughout the day
Eat slowly and stop when you start to feel full
If nausea is persistent, ask your doctor about anti-nausea medication
For constipation: increase fibre, water, and gentle movement

When to call your doctor

Contact your doctor if you experience severe or persistent vomiting, sudden severe abdominal pain (possible pancreatitis), signs of gallbladder problems (pain in upper right abdomen), or any symptoms that concern you.

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