Can You Get Dizzy From Mounjaro? (October 2026)

01 · Your next step

What to do if Mounjaro makes you feel dizzy

Treat dizziness as information to pass to your prescriber, not something to push through alone. Mounjaro is a prescription medicine, and a symptom that is new since you started or since a dose change is exactly what your monthly review exists to catch.

Before you contact your prescriber, jot down a few details. They make the conversation far more useful than "I feel a bit off".

• When it happens: after standing up, after the injection, in the morning, or after skipping a meal.
• How long it lasts: seconds, hours or most of the day.
• What else is going on: nausea, being sick, diarrhoea, or eating and drinking noticeably less than usual.
• Your dose history: which pen you are on, and when you last moved up a strength.
• Your other medicines: especially insulin or a sulfonylurea if you have type 2 diabetes.

If you are an EverydayMeds customer, our prescribing team offers side-effect support and ongoing monthly reviews, and you can reach support Monday to Friday, 9am to 5pm, by email at support@everydaymeds.co.uk, through the account portal chat, or on 0333 207 0413. If you are not yet a customer, our free online consultation lets a GPhC-registered prescriber review your health history first.

02 · Safety first

When dizziness needs urgent help

Get medical help straight away if you faint, if the dizziness comes on suddenly and severely, or if you feel suddenly very unwell. Call 999 in an emergency, or use NHS 111 if you are unsure how urgent it is. Do not wait for your next scheduled review.

For milder, on-and-off lightheadedness, contact your prescriber. Until you have spoken to someone, avoid driving or operating machinery if you feel unsteady, and sit or lie down when it comes on. That is ordinary common-sense safety, not a treatment.

03 · Why you might feel dizzy

Why you might feel dizzy on Mounjaro

The honest answer is that dizziness has several possible causes, and only a clinician who knows your history can tell which applies to you.

Mounjaro (tirzepatide) activates two gut-hormone receptors at once, GIP and GLP-1. Together these help regulate appetite, slow how quickly the stomach empties, and improve the way the body responds to insulin.¹ In practice, most people feel fuller sooner and less hungry between meals. That is how the medicine supports a reduced-calorie diet, but it also means your eating and drinking pattern can change quickly after starting or stepping up.

That is why prescribers ask about the practical picture when someone reports feeling dizzy:

• Are you eating and drinking noticeably less than before?
• Are you having nausea, sickness or diarrhoea alongside the dizziness?
• Do you take other medicines that could contribute?
• Did the dizziness start after a dose change?

None of these questions implies you did anything wrong. They help your prescriber decide whether to adjust your plan, check your other medicines, or look for a cause unrelated to Mounjaro altogether. Dizziness is common in everyday life and has many causes that have nothing to do with a medicine. Our guide to feeling sick on Mounjaro covers the digestive side effects that sometimes travel with it.

04 · Drinking, eating and fluids

What happens if you don't drink enough on Mounjaro?

Mounjaro slows how quickly the stomach empties and makes you feel fuller sooner, so some people notice they eat and drink less without trying.¹ If you also feel dizzy, you should say so at your review, because your prescriber may want to look at your overall intake and any other symptoms.

• Tell them roughly what you eat and drink in a typical day now compared with before treatment.
• Mention any days when you could barely eat or drink.
• Mention any sickness or diarrhoea, and how long it lasted.
• Say whether the dizziness is linked to meals, or to standing up.

Mounjaro is meant to be used alongside a reduced-calorie diet and increased physical activity, not as a reason to eat very little.² Reduced-calorie is not the same as barely eating. If appetite has dropped so far that regular meals feel impossible, that is a conversation to have with your prescriber rather than something to tolerate. Our guide on getting the most from Mounjaro covers building a routine that works alongside the medicine.

05 · Diabetes medicines

Dizziness if you take insulin or a sulfonylurea

If you take insulin or a sulfonylurea, tell your prescriber about any dizziness straight away. Doses of those medicines may need adjusting when Mounjaro is added, because of the risk of low blood sugar.¹³ It does not mean the medicines must never be combined. It means the combination needs monitoring and, sometimes, a dose change made by the clinician who prescribes them.

Do not adjust insulin or a sulfonylurea yourself on the basis of anything you read online. Contact your diabetes team or prescriber, describe when the dizziness happens in relation to meals and doses, and follow their instructions. If you are not sure whether a medicine you take counts as a sulfonylurea, ask your pharmacist or check the label.

When you start treatment with us, your prescriber reviews your current medicines as part of the consultation, so list everything you take, including over-the-counter products and supplements.

06 · Head feeling weird

Why does my head feel weird on Mounjaro?

The side-effect list in the patient leaflet is the place to check whether a symptom is recognised.¹³

For symptoms you cannot find in the leaflet, do not assume they are caused by Mounjaro, and do not assume they are not. If a symptom is not on the leaflet list, it is not a listed side effect, but still tell your prescriber, because other causes matter too. Sleep, stress, other medicines, illness and eating patterns can all affect how your head feels.

You can report a suspected side effect yourself through the MHRA Yellow Card scheme, whether or not it is listed.¹⁹ Reports from patients and clinicians help regulators monitor medicines after they are licensed. For related reading, see our page on Mounjaro dizzy spells.

07 · Dosing interval

Can you take Mounjaro every 10 days?

No. Mounjaro is a once-weekly injection, and the weekly schedule is the licensed way to use it.¹ Do not stretch the interval, skip doses or take extra ones.

If you are tempted to space doses out because of dizziness or other side effects, that is a signal to speak to your prescriber, not to improvise. They can look at your dose, your symptoms and your other medicines, and decide on a plan that is safe for you. Changing the interval on your own can make it harder for anyone to work out what is causing your symptoms.

If you miss a dose or are unsure when to inject, follow the patient information leaflet and ask your prescriber or pharmacist.¹³

08 · Who should not take it

Who should not take Mounjaro, and what to avoid?

Whether Mounjaro is suitable depends on your health history, so a prescriber has to decide. For weight management it is licensed for adults with a BMI of 30 or above, or a BMI between 27 and 30 with at least one weight-related condition such as high blood pressure, high cholesterol, obstructive sleep apnoea, cardiovascular disease, prediabetes or type 2 diabetes. It must be used alongside a reduced-calorie diet and increased physical activity. A prescriber will assess your BMI, medical history and current medicines before deciding.¹

You should not take Mounjaro if you are allergic to tirzepatide or any of its ingredients, and it should not be used during pregnancy or while trying to conceive. Your prescriber will take extra care, or may recommend against treatment, if you have a history of pancreatitis, severe gut or digestive disease, diabetic retinopathy, or gallbladder problems. Always share your full medical history and medicine list during consultation. Mounjaro must not be used during pregnancy, and it should be stopped at least one month before trying to conceive. If you become pregnant during treatment, stop the medicine and tell your prescriber promptly. One interaction worth knowing about from MHRA guidance: the medicine can reduce absorption of oral contraceptives because stomach emptying slows, so ask your prescriber about contraception.⁷ The SmPC advises switching to a non-oral method, or adding a barrier method (such as condoms), for 4 weeks after starting Mounjaro and for 4 weeks after each dose increase.¹

Tell your prescriber about everything you take, including alcohol habits, and ask what applies to you. If you ever feel a medicine is not agreeing with you, report it through the Yellow Card scheme as well.

09 · Worst side effects

What are the worst side effects of Mounjaro?

The most serious side effects in the UK patient leaflet are an inflamed pancreas (acute pancreatitis, uncommon), with severe, persistent stomach pain, with or without being sick: stop using Mounjaro and get medical help straight away. The other is a severe allergic reaction (rare), with breathing problems, rapid swelling of the lips, tongue or throat, or a fast heartbeat: get medical help straight away. Read the patient leaflet before you start, and again if you develop symptoms.

Anything severe, sudden or alarming needs medical help straight away. Anything persistent or that worries you needs a conversation with your prescriber. Anything you suspect is a side effect can be reported to the Yellow Card scheme.¹⁹

Other worries also come up around the medicine, and we have covered them honestly elsewhere, for example in our guide on Mounjaro and cancer concerns. If you are weighing up treatment options generally, our overview of weight loss treatments sets out the licensed choices.

10 · NHS and private

NHS or private: where to get support for side effects

Mounjaro is available on the NHS, but access is being phased in over several years. NICE recommends it for adults with a BMI of at least 35 plus at least one weight-related condition, and the NHS primary-care rollout began in June 2025 with the highest-need groups first, initially BMI 40+ with four or more qualifying conditions.⁴⁶ Full rollout is expected to take years, which is why many people who meet the licensed criteria choose regulated private treatment.

Whichever route you take, make sure someone is responsible for reviewing you. If you are prescribed privately, check that follow-up is part of the service. With us, ongoing monthly reviews, dose-titration and follow-up assessments by the prescribing team are included, along with side-effect support. Repeat orders re-check suitability, and there is no auto-shipping, so every new pen follows a fresh look at how you are getting on.

If dizziness is troubling you and you cannot reach your prescriber, your GP or NHS 111 is always a valid route. You do not need to wait for a scheduled review.

11 · Evidence on results

Weighing side effects against benefit

A side effect matters more when you can see the benefit it is buying, so it helps to know what trials found. In the SURMOUNT-1 trial of 2,539 adults, people taking tirzepatide alongside diet and exercise lost on average 15% of their body weight on 5mg, 19.5% on 10mg and 20.9% on 15mg over 72 weeks, compared with 3.1% with lifestyle changes alone.² For someone starting at 100 kg, 20.9% is about 21 kg.

These are trial averages, and individual results vary. Treatment works alongside a reduced-calorie diet and increased physical activity, not instead of them. Trial averages do not predict your own result, and they do not tell you how you will tolerate any given dose.

That is the right frame for a conversation with your prescriber: your symptoms, your goals and your dose, considered together. If dizziness is making treatment hard to continue, say so. Sometimes the answer is a plan change; sometimes it is stopping. That decision belongs to you and your prescriber, not to a forum thread.

12 · Serious side effects

Serious side effects: when to get help straight away

Serious side effects are uncommon but need urgent attention. Seek immediate medical help for: severe, persistent stomach pain that may spread to your back, with or without vomiting (possible pancreatitis); pain in the upper right abdomen, fever or yellowing of skin/eyes (possible gallbladder problems); or signs of a severe allergic reaction such as swelling of the face or throat and difficulty breathing. If you take insulin or a sulfonylurea alongside Mounjaro, watch for low blood sugar (shakiness, sweating, confusion) — your prescriber may need to adjust those medicines.¹