Understanding Mounjaro side effects and how to reduce them

To manage the symptoms of heartburn, we recommend lifestyle changes, such as:

• avoiding certain foods and drinks like citrus or acidic foods, fatty or spicy foods, coffee and alcohol
• light physical exercise such as yoga or stretching
• finding ways to relax, as stress may make it worse
• eating smaller, more frequent meals
• avoiding eating within 3 to 4 hours of going to bed, or lying down just after eating
• avoiding or quitting smoking
• not wearing tight clothing, especially around your stomach

Constipation on Mounjaro is very common, but may be improved by adjusting your diet and exercising more. If you are experiencing constipation, try:

• eating a balanced diet (learn more on NHS Eatwell Guide)
• eating fruits containing sorbitol such as grapes, raisins, apricots, apples, raspberries, and strawberries
• gradually increasing fibre in your diet
• including wheat bran, linseed, or oats in your diet
• increasing your physical activity to help move food through your system, such as going for a walk after food or using a treadmill

If you have already made diet and nutritional changes and have not seen any effect on your constipation, speak with your doctor or a pharmacist. They may suggest a laxative.

If you have already tried laxatives and they have not helped, see your doctor if you:

• are regularly constipated
• are regularly bloated
• have blood in your stool (poo)
• feel tired all the time
• are taking medication that causes constipation (opioids)
• notice sudden changes in toilet habits
• have stomach pain

Adjusting your toilet routine

If you’re struggling to go to the toilet, keep track of when you do and:

• try to go to the toilet regularly, at a regular time
• do not force it, if you cannot go in the time it usually takes to have a wee, try again later
• when you need to go, do not delay it

We recommend raising your feet or putting your feet on a footstool when you are on the toilet if you are struggling to pass stools (poo).

Diarrhoea can be treated in a very similar way to nausea and vomiting. If you get diarrhoea when taking Mounjaro, make sure to:

• stay hydrated by drinking water or another liquid if you prefer, like squash
• avoid fatty or spicy foods as this may make your symptoms worse

Speak to your doctor if the diarrhoea worsens or does not improve after a week.

If you experience dizziness on Mounjaro, there are several ways to manage it effectively:

• try to lie down or rest until it passes
• avoid any tasks that put yourself or others in danger – for example, driving or lifting heavy objects
• if you have dizziness when standing, get up carefully and slowly
• if you get dizzy just after taking Mounjaro, make sure to eat and drink before your scheduled dose, sit down when taking your medication, and make sure to get someone to help you
• stay hydrated, as dehydration could be a cause of your symptoms
• eat enough to stabilise your blood sugar and avoid long periods of fasting

If these do not help or you have type 2 diabetes and other symptoms of low blood sugar, you should speak with your doctor right away.

Dietary changes can make a big difference in reducing or preventing sulphur burps while on Mounjaro, such as:

• reducing your intake of sulphur-rich foods like eggs, meat, and poultry
• opting for fibre-rich meals that are easier to digest to support a healthier digestive system and reduce gas buildup
• taking probiotics to balance gut bacteria

To help manage headaches from Mounjaro at home, we recommend you:

• drink plenty of fluids – to ensure you are hydrated
• avoid alcohol – which can make you more dehydrated
• speak with a pharmacist – who can advise you on the right painkillers, such as paracetamol
• get plenty of rest – make sure you’re getting enough sleep and nap through the day if you think you need it

After taking Mounjaro, you may feel like you can eat less and do not crave food as much. You may also feel nauseous, or have other side effects, though this should be mild and temporary. Side effects often get better with time, while the benefits of Mounjaro, like reduced appetite, improve as you move up the dosage schedule.

It’s rare, but Mounjaro may not be the right medication for you if you do not feel its effects, such as a lowered appetite, even after reaching a higher dose, or you get persistent side effects.

Tiredness is a common side effect of Mounjaro. While it’s not known exactly why this happens, it could be caused by side effects, your body adjusting to the medication, or your body adjusting to a lower calorie intake and more exercise.

While this side effect can be bothersome, it typically improves over time. Studies have shown that tiredness becomes less common after the 8-week mark with semaglutide, a similar GLP-1 medication. If persistent tiredness continues to affect your daily life, it’s important to speak to your doctor for advice. They may run blood tests to check for nutritional deficiencies.

Some people on weight loss medications like Mounjaro have reported changes or disruptions to their menstrual cycle. However, this is more likely caused by weight loss than the medication itself, with no studies showing that Mounjaro affects the menstrual cycle.

Sudden or rapid weight loss can sometimes be interpreted by your body as stress, leading to irregular or missed periods as your body adapts. These changes are often temporary. If you notice changes to your normal cycle or experience late periods on Mounjaro, there’s usually no need to worry. If your cycle changes persist for more than a couple of months or feel unusual, make sure to speak to your doctor.

Please note: If you’re using oral contraception alongside Mounjaro, the medication can affect how it’s absorbed, so it’s a good idea to use a barrier method like condoms during the first 4 weeks of treatment or after increasing your dose. If your periods become irregular or stop, and you have any other symptoms like nausea, take a pregnancy test.

Hair loss is a common side effect of Mounjaro. However, it’s likely due to rapid weight loss causing the body to go into ‘stress’, nutrient deficiency due to less food intake, or other changes in diet or lifestyle. There is no evidence that Mounjaro affects the hair follicles or causes baldness.

If you want to reduce or prevent hair loss while on Mounjaro, we recommend:

• eating balanced, nutritious meals rich in minerals and vitamins
• managing your stress levels
• cutting down on smoking and vaping, since nicotine intake can sometimes disrupt hair follicle growth
• planning for steady, consistent weight loss, rather than rapid weight loss, which can cause temporary hair loss

If you’re concerned about hair loss or other side effects, get in touch with your doctor for advice.

Some people who take Mounjaro report feeling cold. This may be due to the medication, side effects, or could be caused by a reduction in calories and body fat. If you are feeling cold since taking Mounjaro and it is bothering you or not going away, speak with your doctor.

There may be a link between depression and Mounjaro, however, there is not enough evidence yet to say whether this is a side effect of Mounjaro or caused by something else.

If you have already been diagnosed with depression before starting your treatment with Mounjaro, or if you’re experiencing depression after starting your treatment, speak to your doctor. They may recommend an alternative weight loss treatment or starting a separate treatment for depression.

Erectile dysfunction is not a known side effect of Mounjaro. Sometimes people who are overweight or have weight-related health conditions like prediabetes can get erectile dysfunction, so this may improve as you lose weight.

If you’re experiencing symptoms of erectile dysfunction, we have a range of erectile dysfunction treatments available. Simply start a consultation, and one of our doctors will review your health and symptoms. They will then prescribe you a treatment if necessary.

Mounjaro does not typically cause dehydration directly, but ongoing or severe gastrointestinal-related side effects can. Some patients experience ongoing side effects such as nausea, vomiting, and diarrhoea, which can lead to dehydration. You can manage dehydration by drinking plenty of water throughout the day and avoiding alcohol and caffeine (which can worsen symptoms).

Make sure to speak to a doctor straight away if you’re struggling to keep liquids down, especially if you have other symptoms like dizziness and weakness.

Insomnia is not a listed side effect of Mounjaro, though it has been reported by some patients. There is no evidence to suggest that insomnia is caused by Mounjaro, but some people can experience anxiety, or other symptoms like vomiting and diarrhoea, which may impact a normal sleeping schedule.

If you’re experiencing insomnia while on Mounjaro, be sure to stick to a consistent bedtime routine, avoid caffeine in the afternoon and evening, and make sure that you’re keeping track of when your insomnia happens. If your lack of sleep is affecting your daily life or you have chronic insomnia (over a few months), we recommend getting in touch with your doctor to discuss insomnia treatment.

The most common reason why you feel hungry while taking Mounjaro is that your body is still adapting to the treatment. It takes about 4-8 weeks for Mounjaro to reach a ‘steady state’, where the drug is stable in your blood. Before this 8-week point, there’s a chance that you’ll still experience hunger and cravings.

It’s also possible that your Mounjaro dose is too low to suppress your appetite fully, and you may feel its effects better at a higher dose. For some people, appetite suppression is noticed from day 1 of treatment, but the higher the dose, the stronger these effects will be.

Aside from not being on the higher doses yet, other things can cause feelings of hunger, such as:

• pre-existing food habits and cravings – these can be difficult to shake, especially with sugar and ultra-processed food. These foods are designed to be addictive, and if they’re in your diet already, you may feel like you ‘need’ to eat them, more out of habit than hunger. Food dependence in general, including emotional eating, can also contribute to cravings during your treatment.
• general lifestyle and physiological factors – under/over-exercising or lack of sleep can affect appetite hormones and make us feel hungrier than usual, even while on weight loss medications.

If you’re concerned about the progress of your treatment, or you’re struggling to manage your food intake, speak with your doctor.

Sugar cravings while on Mounjaro can happen for the same reasons you might experience hunger. These include medication-related causes (not at the right dose yet), existing eating and craving habits, and other factors like lack of sleep.

If you are on treatment for type 2 diabetes, Mounjaro side effects can also mimic the symptoms of low blood sugar, including hunger and sugar cravings. If you’re experiencing these symptoms, it’s important to keep track of when they occur and for how long, and let your doctor know about any concerns you may have.

Not necessarily. The side effects of Mounjaro and Wegovy are very similar, because they are both GLP-1 medications that work on the same pathways. However, everyone responds differently to treatments, so if you get side effects on Mounjaro, you may not on Wegovy.

You should speak to your doctor if you are wondering about whether to switch from Wegovy to Mounjaro due to side effects.

Not necessarily. Everyone responds differently to different treatments. Ozempic contains semaglutide and so has similar side effects to Mounjaro. Ozempic is only a diabetes medication, not a weight loss medication. Mounjaro can also be prescribed for type 2 diabetes, but they are not really comparable for weight loss.

In animal studies, there have been reports of thyroid C-cell tumours (a type of thyroid cancer) in rats that were given tirzepatide. However, no human trials have found an increased risk of cancer from using Mounjaro.

While there have been no reports, it cannot be completely ruled out, so speak to a doctor straight away if you experience any symptoms like hoarseness while speaking, difficulty swallowing, or lumps in the neck while using the treatment.