Mounjaro

Mounjaro (tirzepatide) is a weight loss treatment that comes in the form of a weekly self-injectable pen. We can prescribe Mounjaro if it’s suitable for you.

Mounjaro is an injection pen used for weight loss and to treat type 2 diabetes.

They are the same medicine, containing the same active ingredient (tirzepatide) and work the same way. The difference is the name: Zepbound is the US name for the weight loss management medicine, whereas in the UK, it’s licensed under Mounjaro. Zepbound is not licensed in the UK.

The active ingredient in Mounjaro is called tirzepatide.

Tirzepatide works on two hormonal receptors: glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP). You may have heard of GLP-1 from other weight loss injections.

GLP-1 helps to regulate blood sugar levels, which in turn talks to the brain to make you feel less hungry and prevent cravings. It also slows down the emptying of the stomach to keep you feeling fuller for longer.

GIP regulates energy balance in the brain and fat cells, enhancing the GLP-1 effect of suppressing your appetite and improving sugar control.

Mounjaro has been shown to have greater weight loss potential than medicines that work on GLP-1 alone by mimicking the effects of both these naturally occurring hormones.

If you’re wondering how much weight you can lose on Mounjaro, clinical trials have shown that patients could achieve at least 20% weight loss after using tirzepatide for 72 weeks (18 months) combined with healthy lifestyle changes.

Mounjaro is not suitable in some medical circumstances, for example, if you use some other diabetes medicines, have severe problems with digesting food, or have a history of pancreatitis or thyroid cancer. If you’re allergic to tirzepatide or any of the other ingredients in this weight loss injection treatment, you must not use Mounjaro.

When you fill out our online questionnaire, you must give us a full medical history and details of any conditions or other medicines you’re taking. This ensures we can prescribe weight loss treatment that’s suitable and safe for you.

As Mounjaro is a new weight loss medicine available in the UK, it has been assigned a black triangle, which means it will be closely monitored for adverse effects.

The starting dose of Mounjaro is 2.5 mg once weekly. After 4 weeks, the dose should be increased to 5 mg once weekly. If needed, dose increases can be made in 2.5 mg increments after a minimum of 4 weeks on the current dose. The recommended maintenance doses are 5, 10 and 15 mg.

Mounjaro Treatment Timeline

We can also prescribe other medicines to help support your weight loss and weight management journey. Wegovy and Saxenda are weight loss injection treatments that work similarly to Mounjaro. Orlistat and Xenical are capsule medicines that help your body eliminate the extra fat in your diet.

Making healthy lifestyle changes, such as improving your diet and increasing activity, can help with weight loss and also help you to live a healthier, happier life.

Common Mounjaro side effects should be mild and are likely to lessen or even disappear after your body gets used to the treatment. We understand that it’s still tough to live with these discomforts, though, and so we’ve put together some tips for managing these where possible:

• Make sure to inject yourself with the treatment at the same time and day each week, so your body has a regular interval between each dose.
• Stay hydrated, sipping water and other clear liquids if you’re experiencing nausea, vomiting or diarrhoea. It may also help to eat smaller meals more regularly and avoid anything that smells or tastes too strong.
• If you’re struggling with constipation, increase your fibre intake, stay hydrated, and eat small fruits such as prunes, figs, or grapes. Ensure you’re also getting regular activity, such as short walks.
• To ease a headache, relax in a quiet space, take a simple pain relief medicine like paracetamol, drink plenty of water, and try relaxation techniques such as meditation and DIY scalp massage.

The best places to inject Mounjaro are ones with the most fat. These are: your tummy (although make sure to inject more than 5 cm away from your belly button); the front of your thighs; or your upper arms. It’s vital that you change injection sites regularly.

You can inject it in the same area (e.g., tummy), but choose a different spot in that area each time.

Mounjaro should start working immediately, but it could take several weeks until it has a noticeable effect on regulating your blood sugar level and impacting your appetite and eating habits.

If you’re using Wegovy, you’ll need to wait 1 month before switching to Mounjaro. If you’re using Saxenda, you’ll need to wait 3 days before switching to Mounjaro. This is called the 'washout' period, and gives the body time for the first drug to leave the system.

All patients using Mounjaro for the first time will start with 2.5mg. Remember, Mounjaro may not suit you (even if you're using another weight loss medicine). We’ll assess if it’s right for you during your consultation.

Wegovy and Mounjaro are weekly injection pens and work similarly to aid weight loss. Mounjaro has proven more effective in clinical trials, as it works on GLP-1 and GIP hormones, whereas Wegovy only works on GLP-1.

However, Mounjaro is a new medicine in the UK, so we don’t have as much safety data on it as on other medicines in the long term. Deciding if or which medicine is right for you will depend on different factors, which we’ll assess during your consultation.

We recommend you keep using it if you’re already on Wegovy (or Saxenda) and losing weight. Keep in mind, weight plateaus are normal on your weight loss journey.