mybmi logoHome

Does Wegovy cause headaches?

Written by:
Thomas Kolbe-Booysen
Thomas Kolbe-Booysen,
13 Oct 2026 • 9 min read
Reviewed and fact-checked:
Niya Mansuri
Niya Mansuri, Prescribing Pharmacist, GPhC No. 2087150
Woman struggling with a headache while working on her laptop

Headache is one of the most common side effects of Wegovy, with the patient leaflet saying it may affect more than 1 in 10 people. So, if you’ve had a Wegovy headache, you’re certainly not alone.

Headaches can make it harder to focus on work or keep up with day-to-day life. They can certainly be disruptive. But they usually go away with time, and there are also certain remedies and lifestyle changes that can help you manage them.

In this guide, we’ll cover the likely causes, practical ways to find relief, and when to get medical help.

Are headaches an actual side effect of Wegovy?

Yes. Headache is listed as a very common side effect in the Wegovy patient leaflet, alongside other side effects like feeling sick (nausea), diarrhoea, constipation, and feeling weak or tired.

But not every headache you get while taking Wegovy is caused by semaglutide (the medicine in Wegovy). In fact, around 90% of people have a headache disorder at some point in their lives, according to research from an Irish teaching hospital.

Stress, bad posture, eyesight problems, and drinking too much alcohol can all cause headaches, says the HSE. So can medical conditions such as migraine, or a cold or flu. If your headaches started before Wegovy, it’s worth thinking about what else might be going on.

Why does Wegovy cause headaches?

There isn’t one single reason. While researchers have proposed several explanations, these haven’t established a single cause. Even so, Wegovy can change how much you eat and drink, which can lead to headaches.

Dehydration

Wegovy can make you feel sick, be sick, or have diarrhoea. These side effects can cause loss of fluids (or dehydration), says the leaflet.

A review of headaches and glucagon-like peptide-1 (GLP-1) medicines like Wegovy found that dehydration is the main cause of headaches during treatment. It’s one more reason why hydration matters during weight loss.

Eating less

Wegovy helps you feel fuller and less hungry, says the leaflet. And when you’re not hungry, it can be easy to skip meals. Not eating regular meals, long periods without food, and cutting back on calories can all trigger headaches. This is referred to as a “hunger headache” and is often caused by the dip in blood glucose that comes with not consuming enough food.

Changes in blood sugar levels

On the topic of blood glucose, the patient leaflet also lists headache as a warning sign of low blood sugar (hypoglycaemia), along with cold sweats, a fast heartbeat, feeling very hungry, and shaking.

Low blood sugar is uncommon when GLP-1 medicines are used on their own. But the risk is higher if you also take insulin or a sulphonylurea (a type of diabetes medication). If you do, your doctor may ask you to test your blood sugar levels and will tell you what to do if you notice warning signs.

Feeling tired

Feeling weak or tired (fatigue) is another very common side effect of Wegovy. And sleep problems can cause tension headaches, according to Migraine Ireland.If you struggle with fatigue on Wegovy and need practical advice to manage it, read our guide to whether Wegovy makes you tired.

When do you usually get headaches from Wegovy?

Usually in the first few weeks of treatment, or after a dose increase. Depending on you response to the treatment, your dose is increased gradually over 16 weeks, and the leaflet says headaches reappear during this time. They are also most often reported early in treatment.

But everyone is different, and not everybody gets side effects. Try noting when your headaches happen, and what you’d eaten, drunk, and how you’d slept. This can help you spot patterns or triggers, rather than assuming every headache is down to Wegovy.

How long do headaches from Wegovy last?

There’s no set timeframe. The leaflet says headaches usually go away over time, and the review describes them as usually short-lived. In general, a headache can last 30 minutes, several hours, or sometimes several days.

What do these headaches feel like?

Headaches linked to GLP-1 medicines are generally mild and do not stop you doing everyday things, according to the review.

A tension headache can feel like pain on both sides of your head, or like something is pressing on your head or tightening around it, says the HSE. This is different from a migraine, which is more severe and is characterised by throbbing pain on one side, with feeling sick or sensitivity to light.

Can Wegovy also cause migraines?

Migraine isn’t listed as a side effect in the Wegovy patient leaflet. But if you already get migraines, the HSE’s tips for preventing them include staying hydrated and not skipping meals, which can be harder while you’re getting used to Wegovy.

A migraine is more than a bad headache. According to the HSE, it’s usually a moderate or severe throbbing pain on one side of your head. It can come with feeling or being sick, and sensitivity to movement, light, sound, or smell.

Obesity has also been linked to long-term headache conditions, including migraine. And in a small study of people with raised pressure inside the skull (idiopathic intracranial hypertension), those taking GLP-1 medicines had a bigger drop in monthly headache days after six months than those who weren’t.

If you think you’re having migraines, see your GP for a proper diagnosis.

How to manage and prevent headaches on Wegovy

A few small changes to how you eat, drink, sleep, and move may help ease headaches or stop them starting.

Lifestyle adjustments

  • Stay hydrated. The leaflet says it’s important to drink enough fluids. The HSE advises drinking enough so your pee is pale yellow.
  • Avoid skipping meals. Don't skip meals when you have a headache, even if you don’t feel like eating. If you’re struggling to get in enough food while on Wegovy, read our guide to eating well when your appetite is small.
  • Stick to a sleep routine. Both too little and too much sleep can cause headaches. it's important to establish a pattern that works for you. The HSE recommends 7-9 hours a night for adults.
  • Keep active. A review of six studies found aerobic exercise (activity that raises your heart rate) may slightly reduce the number of migraine days.
  • Cut back on caffeine and alcohol. Limiting both to help prevent headaches and migraines
  • Find ways to relax. Stress can also make headaches worse.

Over-the-counter treatments

You can buy these from pharmacies in Ireland:

  • Ibuprofen. The HSE says it can treat headaches. Take it with a meal, snack, or a drink of milk or water. Ask a pharmacist or a doctor first if, for example, you take other medicines, have asthma, or have had stomach ulcers.
  • Oral rehydration sachets. If you’ve been sick or had diarrhoea, your pharmacist can recommend these powders, which you mix with water, says the HSE.
  • Paracetamol. The HSE says adults can usually take up to four doses (eight tablets of 500 milligrams) in 24 hours, at least four hours apart.

While you can take both paracetamol and ibuprofen at the same time, we recommend trying each separately first to assess which works best for you. Ask a pharmacist or doctor if you are unsure which painkiller is appropriate

The HSE also advises not using the maximum dose of painkillers more than two days a week, as this could make headaches harder to treat over time.

Other remedies

  • Cold or heat packs: Theses can help during migraines or tension headaches.
  • A dark room: Lying down in a dark room may help during a migraine attack

“Headaches can happen when you start Wegovy, but they’ll often ease as your body gets used to treatment. Keep drinking plenty of fluids, try smaller regular meals if your appetite is low, and give yourself time to rest. Gentle exercise may help, too, and your cliniciancan advise on suitable pain relief if you need it.”

Niya Mansuri
Niya MansuriPrescribing Pharmacist

When to get medical help

Speak to our clinicians or your GP if your headaches aren't getting better, are getting worse, or keep coming back.

Call 112 or 999 if you have a sudden, very painful headache unlike anything you’ve had before. The HSE also says to call if you have weakness in one or both arms or one side of your face, slurred speech, or a headache with symptoms such as a high temperature (fever), a stiff neck, confusion, or a rash.

Get support with your Wegovy side effects

Headaches on Wegovy can be frustrating. But they usually go away over time, and there’s plenty you can do in the meanwhile. For more information on other side effects, check out our guide to Wegovy side effects.

And if you’re a myBMI patient, you don’t have to manage side effects alone. Every myBMI treatment plan includes clinical support from our IMC-registered doctors, plus free medication for certain side effects if deemed appropriate.

Find out more

Sources

Wegovy headaches

Frequently Asked Questions

More like this

View All
Woman sleeping on sofa during daytime
WegovyWegovy tablets

Does Wegovy make you tired?

In this guide, we’ll look at why Wegovy may make you tired, what you can do to manage fatigue, and when it’s worth speaking to a healthcare professional.

Alexandra Smith
Alexandra Smith

13 Oct 2026

6 min read

A group of friends drinking cocktails on a sunny day
WegovyWegovy tablets

Can you drink alcohol while taking Wegovy?

If you’re taking Wegovy, you may be wondering whether you can still enjoy an alcoholic drink from time to time. Here’s how to do so safely.

Morgan Pennington
Morgan Pennington

13 Oct 2026

7 min read

Woman feeling poorly, sipping water from a glass while sitting in an armchair, covered in a blanket.
WegovyWegovy tablets

How do you stop feeling sick on Wegovy?

A smaller appetite can be a welcome part of weight loss. But feeling too nauseous to enjoy your food is a different matter. Here’s what to do if you’re feeling sick on Wegovy.

Morgan Pennington
Morgan Pennington

13 Oct 2026

8 min read