Can headaches and diarrhea be side effects of Ozempic (semaglutide) after 3 weeks of treatment?

Yes, Headache and Diarrhea Are Common Side Effects of Ozempic (Semaglutide)

Both headache and diarrhea are well-documented side effects of Ozempic (semaglutide), and experiencing them during your third week of treatment is entirely consistent with the expected adverse effect profile of this medication. 1, 2

Gastrointestinal Side Effects Are the Most Common

• Diarrhea is one of the most frequently reported side effects of semaglutide, occurring in 16-32% of patients depending on the dose, compared to 7-16% with placebo. 3, 1
• Nausea, vomiting, diarrhea, abdominal pain, and constipation occur in the majority of patients taking Ozempic, though these symptoms are typically dose-dependent and transient. 1, 2
• Most gastrointestinal adverse effects, including diarrhea, are most pronounced during initial treatment or dose escalation and typically occur within the first few weeks. 1
• These gastrointestinal symptoms usually improve with continued use or dose adjustment and are considered functional rather than indicating mucosal injury. 1

Headache Is Also a Common Side Effect

• Headache is reported in 8-22% of patients taking semaglutide across various clinical trials. 3, 1
• Headache is listed among the most common adverse effects in the FDA drug label for Ozempic. 2
• Like gastrointestinal symptoms, headaches are often more common during the initial weeks of treatment. 1

Timeline and Your Third Week of Treatment

• Your timing at 3 weeks is precisely when these side effects are most likely to occur, as 70-80% of gastrointestinal adverse effects happen within the first 2 weeks, and many persist into weeks 3-4. 3
• The good news is that 60-65% of gastrointestinal side effects resolve within the first month of treatment. 3
• Most adverse events occur during the first week and typically resolve within a few days to weeks. 4, 1

When to Be Concerned

While headache and diarrhea are common and usually manageable, you should contact your healthcare provider if:

• Diarrhea is severe or persistent, as it can lead to dehydration and potentially cause kidney problems. 2
• You experience signs of dehydration including decreased urination, dizziness, or dry mouth. 2
• Headache is severe or accompanied by vision changes, as semaglutide can rarely affect vision. 2
• You develop severe abdominal pain that doesn't go away, which could indicate pancreatitis. 2
• Symptoms worsen rather than improve over the next 1-2 weeks. 1

Management Strategies

• Ensure adequate fluid intake to prevent dehydration from diarrhea, which is crucial to avoid kidney complications. 1, 2
• Take the medication with food and reduce meal sizes to help minimize nausea and gastrointestinal symptoms. 1
• Avoid high-fat foods, alcohol, and carbonated drinks, which can worsen gastrointestinal side effects. 1
• If symptoms are intolerable, discuss with your provider whether staying at your current dose longer before escalating might be appropriate, as slow titration minimizes side effects. 1

Important Safety Note

Do not stop Ozempic abruptly without consulting your healthcare provider, especially if you're taking it for diabetes management, as this could affect your blood sugar control. 2