Mounjaro

Mounjaro (tirzepatide) is a weight loss injection that mimics natural hormones in your body, and works by reducing your appetite and making you feel fuller for longer. It is most effective when used alongside a low-calorie diet and an exercise plan for healthy weight loss.

Mounjaro has been approved in Ireland for weight loss if you have:

• a BMI (body mass index) of 30 kg/m² or higher (obesity)
• a BMI between 27 and 30 kg/m² (overweight) and a weight-related health condition, such as high cholesterol, high blood pressure, prediabetes, or heart problems

Mounjaro works by reducing your appetite, so you feel fuller after having a meal. This helps you lose weight by making it easier to avoid overeating and snacking, reducing the amount of calories you eat.

Mounjaro contains the active ingredient tirzepatide, which is a type of medication known as both a ‘GIP and GLP-1 agonist’. This means it mimics the effects of naturally occurring hormones that are responsible for regulating your appetite and the speed at which food moves through your intestines. It can also help to stabilise your blood sugar levels by increasing insulin production.

How long does it take for Mounjaro to work?

Mounjaro starts reducing your appetite straight away, but it may take a few weeks to feel the full effect.

Although it can quickly reduce your appetite, it may be some time before you see noticeable weight loss. Weight loss takes time and depends on you sticking to your diet and exercise plan.

You can get a consultation and prescription for Mounjaro online in Ireland from regulated online doctor services like ZAVA. Our doctors provide consultations and prescriptions for weight loss treatments, supported with diet and exercise plans, to help you safely and effectively lose weight.

Can I get Mounjaro over the counter?

No, you cannot get Mounjaro over the counter. Mounjaro is a prescription medication, which means a doctor needs to check that treatment will be safe and effective for you.

The most effective way to inject Mounjaro is by following the instructions given by your doctor. These will include advice on where to inject Mounjaro.

Mounjaro should be injected into a different site each week to minimise irritation and pain. This can still be the same injection site, but you should use a different part of your skin. Find a place that works best for you. You can inject a Mounjaro pen into your stomach, thighs or the back of your arms if someone helps you.

If you do inject Mounjaro into your stomach, leave a 5cm gap around your belly button. For those taking other injectable medications, choose a different site to reduce soreness.

What’s the best time to take Mounjaro?

It doesn’t matter what time of day you take Mounjaro as long as you stick to around the same time each week. This helps your body get used to the treatment and can make it more effective.

Mounjaro injection can be taken with or without food. See the ‘Foods to avoid on Mounjaro’ section for more information.

Can you stay on Mounjaro forever?

When taking Mounjaro for weight loss, you should stay on it at least until you’ve achieved your weight loss goals, unless a doctor suggests otherwise. Your doctor will do regular check-ups to monitor your weight and any side effects you may be experiencing.

What happens when you stop taking Mounjaro?

When you stop taking Mounjaro, the amount of it in your system will slowly drop to nothing. You will lose the blood sugar regulating effect and your appetite will go back to normal. If you’re using Mounjaro for weight loss and stop, you may find that your weight goes back to how it was before starting treatment.

You need to keep to your diet and exercise regime to make sure you don’t put weight back on. Weight loss requires a long-term commitment, even with medication.

You shouldn’t stop taking Mounjaro without speaking to your doctor first.

Like all medications, Mounjaro can have some side effects. However, these won’t affect everyone who uses Mounjaro and your dose will be increased slowly to minimise your chances of getting them.

Very common Mounjaro side effects include:

• nausea (feeling sick) and vomiting
• diarrhoea
• constipation
• low blood sugar (when used alongside certain diabetes medications)

These side effects aren’t usually severe and tend to go away as your body adjusts to the medication.

Common Mounjaro side effects include:

• low blood sugar when used alongside certain other diabetes medications
• low blood pressure
• stomach pain
• indigestion
• constipation
• burping or gas
• bloating
• reflux or heartburn
• decreased appetite
• fast pulse
• being sick (vomiting)
• allergic reactions
• dizziness
• hair loss
• feeling tired
• injection site reactions
• higher levels of pancreatic enzymes in the blood

Uncommon Mounjaro side effects include:

• gallstones
• injection site pain
• inflamed pancreas (also known as acute pancreatitis) – speak to your doctor straight away if you get severe stomach or lower back pain that doesn’t go away
• infection of the gallbladder
• low blood sugar when used with metformin
• higher level of calcitonin (a hormone involved in calcium metabolism) in the blood
• gastroparesis, which is when food goes through your stomach slower than it should

There is always a risk of a severe allergic reaction (anaphylaxis) when using a new medication. If you find it difficult to breathe, get facial or airway swelling, or feel faint and dizzy, call 999.

Some side effects occur only when used to treat diabetes or only when used to treat weight loss. You can find more information in the package leaflet.

Who should not take Mounjaro?

You should not take Mounjaro injections if you:

• are under 18
• are pregnant, trying to get pregnant, or breastfeeding
• are allergic to any ingredients in the Mounjaro pen
• do not meet the criteria for treatment
• have not been approved for Mounjaro treatment by a doctor

Speak to your doctor before taking Mounjaro if you:

• have severe problems with food digestion
• have ever had pancreatitis
• have problems with your eyes (either diabetic retinopathy or macular oedema)
• are on diabetes medication with sulfonylurea or insulin

Foods to avoid on Mounjaro

As Mounjaro is either used for weight loss or regulating blood sugar levels, it should be taken alongside a diet and exercise regime. You don’t have to completely avoid any foods but aim for a balanced diet.

Foods to cut back on when using Mounjaro include:

• greasy or fried foods, especially if you get nausea or vomiting
• anything high in sugar, like chocolate or biscuits

It’s also good to avoid alcohol in large quantities as it lowers your blood sugar. This can increase the chances of having extremely low blood sugar if you are diabetic. Alcohol can also be high in calories and sugar and can lead to binge-eating.

Mounjaro warnings and risks

As Mounjaro can cause vomiting and diarrhoea, it can lead to dehydration if you don’t get enough fluids. Make sure to drink plenty of water while taking Mounjaro and speak to your doctor if these side effects become severe. They may tell you to stop using Mounjaro or lower your dose.

Mounjaro may affect how well the contraceptive pill works. If you’re taking an oral contraceptive, such as the combined contraceptive pill or mini pill, you should:

• use another method of contraception (like condoms) or switch to a non-oral contraceptive for 4 weeks after starting the Mounjaro pen
• do the same for 4 weeks after each Mounjaro dose increase

Mounjaro Interactions

Mounjaro weight loss injections can lower your blood sugar levels too much if taken in combination with sulfonylurea or insulin (other diabetes treatments). Tell your doctor if you’re taking any of these medications, as they may need to adjust your dose.

You shouldn’t take Mounjaro alongside other weight loss injections or tablets, such as liraglutide (Saxenda), Xenical or Mysimba. This could increase the risk of serious health risks and side effects.

For information on any other interactions with medications, including non-prescription and herbal remedies, speak to your doctor.