How common
On Wegovy 2.4 mg, 14% reported headache against 10% on placebo; on the 7.2 mg dose it was 9% against 8% on 2.4 mg and 7% on placebo in that trial.[1] Headache is not in Zepbound's table of reactions seen in at least 5% of patients.[2] So about 1 extra person in 25 gets a headache because of semaglutide.
Possible reasons
No study has examined why. Reasonable contributors are dehydration from vomiting, diarrhea or drinking less; eating much less; changes in caffeine habits when appetite changes; and, in people with diabetes on insulin or sulfonylureas, low blood sugar.[1][2] These are inferences, not findings.
When a headache is urgent
- Sudden, severe headache, the worst of your life
- Headache with sudden vision loss or change: see the vision page
- Headache with weakness, confusion, trouble speaking, fever or a stiff neck
These need emergency care regardless of any medicine.
The short version
Short on the way. A 35-second captioned version of this page is in production for the Fewer Bites channel. It will be embedded here when it is live.
Questions to bring to your prescriber
Print these or screenshot them. They are conversation starters, not a checklist of things to do.
- Could my headaches be related to fluids, food or blood sugar, and how do we check?
- Which pain relievers are safe for me with my kidneys and other medicines?
Education, not advice. This page explains what trials, labels and guidelines report. It does not tell anyone to start, change or stop a medicine. Your prescriber knows your history; this page does not.
Sources
- Novo Nordisk / FDA. Wegovy (semaglutide) injection and tablets, prescribing information, revised 06/2026. label
- Eli Lilly / FDA. Zepbound (tirzepatide) prescribing information, revised 08/2026. label