Does Mounjaro cause headaches? What you need to know

No, headaches are not listed as a side effect of Mounjaro. However, they can commonly be caused by another side effect of Mounjaro, which is low blood sugar (hypoglycaemia). Low blood sugar is more likely if you take Mounjaro as a type 2 diabetes treatment with other diabetes medications.

For example, low blood sugar on Mounjaro is:

• very common when used alongside sulphonylurea and/or insulin
• common when used alongside both metformin and a sodium-glucose co-transporter 2 (SGLT2) inhibitor, either in 2 separate tablets or in a combined tablet such as Xigduo or Vokanamet
• uncommon when used alongside metformin

While low blood sugar is one of the most common reasons for Mounjaro headaches, other things can cause them. Most often, headaches are linked to how your body responds to weight loss, the medication, and appetite changes, rather than the medication itself.

Potential causes for headaches on Mounjaro include:

• low blood sugar – this is more likely if you have diabetes, especially if you take other medications to lower your blood sugar levels
• dehydration – getting very common side effects like feeling or being sick (nausea or vomiting) and diarrhoea can reduce your fluid intake, which can trigger headaches if you do not drink enough
• not eating enough – a reduced appetite may lead to skipped meals or eating too little, which can result in hunger-related headaches and cause your body to go into stress, which could also trigger headaches
• tiredness – feeling tired is a common side effect of Mounjaro and can make headaches more likely
• stress – changing your diet, exercise, and lifestyle habits can put physical and emotional stress on your body, which may cause stress-related headaches
• other Mounjaro side effects – Mounjaro causes several side effects that might cause headaches or make them worse, such as nausea, vomiting, dizziness, and low blood pressure

Although Mounjaro headaches are usually nothing to be concerned about on their own, you must be aware of the signs of low blood sugar, as this can be dangerous if not treated.

You should speak to a doctor straight away if you get a headache alongside symptoms such as:

• sweating
• shakiness
• confusion
• a fast heartbeat
• feeling very hungry

If you have diabetes, your doctor may have already told you what to do if you are taking Mounjaro and get low blood sugar, so you should follow this plan, but still let them know as soon as you can. In an emergency, such as if someone becomes unresponsive, call 999.

Mounjaro headaches can feel different for everyone, and may depend on what’s causing the headache. A Mounjaro headache might feel like:

• a dull, pressure-like sensation or ache
• a feeling of tension or tightness across the forehead and temples
• mild to moderate discomfort

Mounjaro headaches are not typically described as migraines. However, lifestyle triggers such as dehydration, diet and exercise changes, or poor sleep can still bring one on, especially if you’re already prone to getting them.

You might get Mounjaro headaches:

• when you first start treatment
• after a dose increase
• if you get other side effects, such as vomiting, especially if you’re dehydrated

Headaches might also be more likely at the start of treatment as you adjust to new eating habits and an exercise routine.

Headaches from Mounjaro may last for a few hours or a few days, depending on the cause. Some people might experience Mounjaro headaches for a few weeks during the early stages of their treatment or after a dose increase.

Mounjaro headaches are usually temporary and will improve as your body adjusts to the medication or you treat the cause, such as increasing your water intake if you’re dehydrated. If your headaches continue beyond a few weeks, you have other symptoms (especially low blood sugar symptoms), or your headaches become more severe, you should speak to a doctor straight away.

Do Mounjaro headaches go away over time?

Yes, Mounjaro headaches go away over time for most people. They can also be managed and treated with lifestyle changes and over-the-counter medications, which can shorten the length of time you have them.

You should speak to a doctor if you’re taking Mounjaro and your headaches:

• are severe or persistent
• worsen over time
• interfere with your daily life
• happen alongside other symptoms, especially low blood sugar symptoms

If your headaches continue after making lifestyle changes, your doctor may consider adjusting your dose or discussing alternative weight loss treatment options with you.

Can I take painkillers with Mounjaro?

Yes, painkillers like paracetamol are usually suitable to take with Mounjaro. Ibuprofen may also be used, but you should check with a doctor or pharmacist first if you have stomach-related side effects such as nausea, vomiting, or stomach pain. Ibuprofen can also cause stomach irritation and should be taken with food. If you’re not eating much due to Mounjaro side effects, you should avoid ibuprofen and just use paracetamol.

Why do my headaches get worse when I increase my Mounjaro dose?

Your headaches may get worse when you increase your dose of Mounjaro because your body needs to get used to the higher dose. Headaches may also be triggered by other side effects. As your dose of Mounjaro increases, you may notice its effects are stronger, such as appetite reduction. Make sure you’re still eating and drinking enough, or this could cause headaches.

Will the headaches go away if I switch to Wegovy?

It depends on the cause. If your headaches are caused by other side effects, blood sugar reduction, or dehydration, then Wegovy can also cause these, as it works in a very similar way and belongs to the same medication group. Most of the time, headaches on Mounjaro will go away with lifestyle changes, such as making sure you’re drinking enough and managing your blood sugar levels.

Wegovy also causes headaches and is listed as a very common side effect, although some people who switch medications react better to a different active ingredient.

Does the time of day I inject affect headaches?

There is no evidence that the time of day you inject Mounjaro affects whether or not you get a headache. However, it’s recommended that you take your dose at the same time each week to maintain consistent levels of the medication in your body. If you notice you get a headache shortly after your injection, you may prefer to inject in the evening so you can sleep it off.

Should I stop Mounjaro if my headache won't go away?

It might not be necessary to stop Mounjaro if your headache does not go away. As headaches are not a listed side effect of Mounjaro, it’s more likely that they’re caused by something else. You should first focus on your hydration, nutrition, and sleep. If your headaches are persistent or severe, you should speak to a doctor who may consider adjusting your dose or exploring alternative treatment options with you.

Why do I get a headache after injecting Mounjaro?

Getting a headache after injecting Mounjaro might happen because of changes in your appetite, hydration, and blood sugar levels, or as your body adjusts to the medication. While this does not necessarily mean the treatment is unsafe, you should continue to monitor your symptoms and let your doctor know.

Can Mounjaro cause migraines?

No, migraines are not listed as a side effect of Mounjaro. However, they can be triggered by other factors such as dehydration, nausea, or poor sleep, especially if you are already prone to them. If you develop new or worsening migraines on Mounjaro, you should speak to a doctor.

Do you get a headache if you stop taking Mounjaro?

Headaches are not typically reported as a side effect of stopping Mounjaro. However, stopping the medication can lead to changes in your appetite, eating patterns, and blood sugar levels, which may trigger headaches in some people. If you continue to get headaches or other symptoms after you stop treatment, you should speak to a doctor.