Where headache does and does not appear
Zepbound® has two US indications: lasting weight reduction for adults who have obesity, or excess weight together with a related health problem, and treatment of moderate or severe obstructive sleep apnea (OSA) when obesity is also present. [1] Its side-effect data come mainly from two 72-week placebo-controlled trials, which the label calls Study 1 and Study 2 and which are published as SURMOUNT-1 and SURMOUNT-2. Table 1 lists a reaction only if at least 2% of people on Zepbound® reported it and it was more frequent than on placebo. [1]
Headache is not in that table, and the label does not mention it anywhere in section 6.1. For the two OSA trials, the label says reactions were similar to the weight-reduction pool. [1] The table below shows what each official document says about headache and which nearby rows have numbers.
| Document and population | Headache | Closest rows with rates (Zepbound® 5 / 10 / 15 mg vs placebo) |
|---|---|---|
| US label, Table 1, SURMOUNT-1 and -2 (≥2% and above placebo) [1] | Not listed | Fatigue 5 / 6 / 7% vs 3%; dizziness 4 / 5 / 4% vs 2%; low blood pressure 1 / 1 / 2% vs 0% |
| US label, OSA trials (SURMOUNT-OSA, 10 or 15 mg) [1] | Not mentioned | Reactions described as similar to the weight-reduction pool |
| Canadian monograph, Table 2 (≥1% and above placebo) [3] | Not listed | Dizziness 4.1 / 5.5 / 3.6% vs 2.1%; fatigue 4.6 / 5.7 / 6.8% vs 3.1% |
| EU: tirzepatide product information, sold as Mounjaro® [4] | Not listed | Dizziness and low blood pressure “common” (1 in 100 to 1 in 10), mainly in people with overweight or obesity |
| US Medication Guide [2] | Named as a sign of low blood sugar | Low blood sugar risk higher with insulin or a sulfonylurea |
Why there is no Zepbound® page in the EU
The European Medicines Agency has no product called Zepbound®. In the EU, tirzepatide for weight management is authorised under the Mounjaro® name, so the row above comes from Mounjaro® product information and describes the molecule, not a separate Zepbound® document. [4] Its adverse reaction table covers weight-management and sleep apnea trials together with diabetes trials, and headache is not in it.
What research adds
Trial pooling across conditions points the same way. A 2025 meta-analysis of 12 randomised trials of tirzepatide in type 2 diabetes found no difference in headache (risk ratio 1.00), while dizziness was more frequent (risk ratio 1.64). [6] Those were diabetes trials, mostly at Mounjaro® doses, so they describe the molecule rather than Zepbound® users with obesity.
Spontaneous reports tell a different kind of story. An analysis of the EU pharmacovigilance database EudraVigilance found that headache made up 2.51% of tirzepatide reports and flagged it as a reaction not described in the product information. [5] Reports like these come from patients and clinicians who suspect a link; they cannot show that the drug caused the headache or how often it happens.
For people who already have migraine, evidence is thin in both directions. A 2026 case series described two patients whose migraine attacks became less frequent after starting tirzepatide; both also lost weight, and the authors call the cases preliminary. [7]
Three label-backed routes to a headache
If headache is not a listed reaction, why do so many people on Zepbound® report one? The label does not answer that directly, but it describes three situations in which headaches are expected for other reasons.
- Fluid loss. Zepbound®’s commonest reactions are stomach and bowel symptoms, and most nausea, vomiting and diarrhea happened while the dose was being raised. [1] The label warns that such losses can lead to dehydration and kidney injury, [1] and MedlinePlus lists headache among the early signs of mild to moderate dehydration. [11]
- Low blood sugar. In SURMOUNT-2, the trial in adults with type 2 diabetes, readings under 54 mg/dL occurred in 4.2% on Zepbound® versus 1.3% on placebo, and in 10.3% of those also taking a sulfonylurea. [1] The Medication Guide includes headache among the warning signs. [2]
- Untreated or undertreated sleep apnea. The National Heart, Lung, and Blood Institute lists headache among symptoms people with sleep apnea may notice, and MedlinePlus describes headaches that are worse in the morning. [8][9] Zepbound® improved apnea measures in its OSA trials, [1] but the Canadian monograph stresses that it does not replace positive airway pressure for people who need it. [3]
Everyday causes worth ruling out
Most headaches have nothing to do with a new medicine. MedlinePlus names tension headache, linked to tight muscles and stress, as the commonest type, and lists colds, flu, fever and the premenstrual phase among other triggers. [10] For migraine it mentions caffeine withdrawal, lack of sleep and alcohol. [10] Eating less on Zepbound® often changes routines, including how much coffee you drink and when, so it is worth noting those changes too.
Rebound headaches are another possibility: taking pain relievers more than three days a week can keep headaches coming back. [10] And if you take other medicines by mouth, mention them to your pharmacist, because Zepbound® slows stomach emptying and the label says this may affect how some oral medicines are absorbed. [1]
What general guidance suggests
The Zepbound® Medication Guide gives no headache-specific advice. It does say to drink fluids to lower the chance of dehydration, and to contact your prescriber without delay when nausea, vomiting or diarrhea persists. [2] For anyone on insulin or a sulfonylurea, it asks for a conversation about recognising and treating low blood sugar before treatment begins. [2]
For the headache itself, MedlinePlus suggests rest in a quiet, dark room, a cool cloth and relaxation techniques, and keeping a headache diary: when it began, what you ate and drank in the past 24 hours, how long you slept and what ended it. [10] It names over-the-counter pain relievers for tension headaches; [10] ask a pharmacist which suits you, since some interact with other conditions and medicines. If you use a PAP device for sleep apnea, do not stop or change it on your own; the Canadian patient information says that decision belongs to your clinician. [3]
Zepbound® and Mounjaro® are registered trademarks of Eli Lilly and Company. PepLabo is not affiliated with or endorsed by Eli Lilly and Company.
When to get help
| Sign | Who to contact | How fast | Source |
|---|---|---|---|
| A sudden, explosive headache, or the worst headache you have ever had | Emergency services (911 or local number) | Emergency | MedlinePlus [10] |
| Headache with slurred speech, vision change, weakness in an arm or leg, loss of balance or confusion | Emergency care right away | Emergency | MedlinePlus [10] |
| Headache with fever, stiff neck, nausea and vomiting | Medical help right away | Emergency | MedlinePlus [10] |
| Nausea, vomiting or diarrhea that does not go away, with headache or thirst | Your prescriber, promptly (dehydration and kidney risk) | Today | Medication Guide [2] |
| Headache with shakiness, sweating, hunger or confusion, especially on insulin or a sulfonylurea | Treat as possible low blood sugar; tell your prescriber | Today | Medication Guide [2] |
| Morning headaches, loud snoring or daytime sleepiness that continue on treatment | Raise at your next visit | At your next appointment | NHLBI [8]; MedlinePlus [9] |
| Needing pain relievers three or more days a week | Discuss with your prescriber | At your next appointment | MedlinePlus [10] |
