Mounjaro is a prescription weight loss medication which helps to improve effective weight loss. In this complete guide to Mounjaro, we will be answering common questions we are regularly asked about Mounjaro, providing in-depth information on how Mounjaro works to help you decide if it is suitable for you and how to buy it from Pharmacy Prime. 


In this comprehensive medication guide, we will be covering all of the essentials on Mounjaro and its use as a weight loss aid. By reading this guide, you will find out what Mounjaro is, how it works, and if it’s a suitable medication for your needs. This guide will cover the following:

  • What is Mounjaro?
  • How Mounjaro works
  • How to take Mounjaro?
  • Monjaro dosage
  • Is Mounjaro safe?
  • How do you take Mounjaro for weight loss?
  • Potential side effects
  • Who should not take Mounjaro?
  • How can I buy Mounjaro at Pharmacy Prime?

What is Mounjaro?

Mounjaro is a branded name for the medication tirzepatide. It is a GIP/GLP-1 receptor agonist, meaning that it mimics the effects of GIP and GLP-1 which are hormones which regulate satiety within the body. It comes in the form of a pre-filled injector pen, which is self-injected weekly.

Mounjaro is a weight loss medication used to make weight loss more effective in overweight or obese people. It is not intended to be used by itself to lose weight, meaning that it is intended for use alongside a healthy diet and exercise to help a person lose weight.

How Mounjaro works

Mounjaro works relatively similarly to Wegovy in that it is an appetite suppressant (you can read more about this medication in our Wegovy guide). As mentioned above, it is a GIP/GLP-1 receptor agonist, which mimics the effects of the GIP and GLP-1 hormones. These hormones regulate satiety in the body, so Mounjaro is effective in weight loss by making a person feel fuller for longer. 

In addition, Mounjaro also slows the rate at which food is processed in the stomach, known as gastric emptying. This further helps in its effect of making a person feel fuller for longer.

By helping to reduce calorie intake and making a calorie deficit more easily attainable, Mounjaro has been proven to be an effective aid in weight loss. Mounjaro’s effective weight loss management capabilities have been evidenced in clinical trials. In a 72-week trial, weight loss occurred early and continued through the trial.

At the end of the trial, 89%, 96%, and 96% of patients given 5 mg, 10 mg, and 15 mg of tirzepatide once weekly, respectively, had a body weight reduction of 5% or more.

How to take Mounjaro?

Mounjaro is taken through a self-administered injection. This can be done in the upper arms, upper legs, or abdomen. You should ensure that you closely follow the instructions provided with Mounjaro.

If you are prescribed Mounjaro, we will provide you with ongoing support while taking this medication. This will involve regular check-ins to ensure that the titration process and any side effects that you experience are correctly managed. Our specialist physicians will support you throughout the duration of your use of Mounjaro and are always available to provide you with assistance.

Mounjaro dosage

Mounjaro is taken in weekly doses. It is administered through a process called titration, by which medication is given in increasingly higher doses until it is clinically effective. Therefore, Mounjaro is given in an initial dose of 2.5mg, gradually increasing in dose each time after 4 weeks by 2.5mg. A standard treatment plan will happen as follows:

  • Week 1 - 4 -  2.5mg
  • Week 5 - 8 - 5mg
  • Week 9 - 12 - 7.5mg
  • Week 13 - 16 - 10mg
  • Week 17 - 20 - 12.5mg
  • Week 21 - 24 - 15mg

Depending on your body’s reaction to Mounjaro and what your most suitable dosage is, your physician will keep you on a maintenance dose of either 5mg, 10mg or 15mg. Mounjaro may be advantageous for some customers as it has a wider range of licenced maintenance dose levels. Under no circumstances should you increase your dose early unless advised by your physician, as this will likely cause significant side effects. 

Your physician will advise you on how long you will use Mounjaro for weight loss. You should contact your physician if you do experience any side effects while taking treatment.

Is Mounjaro safe?

Mounjaro has been approved for aiding weight loss in the UK by the MHRA since 2023, meaning it is a safe medication to use. However, its use does have some potential side effects, which we detail below.

Potential side effects

As with most medications, Mounjaro has several side effects that could occur as a result of its use. These include:

  • Nausea
  • Constipation
  • Diarrhoea
  • Headaches
  • Fatigue
  • Abdominal pain

This list of side effects is not exhaustive. As a result, you should refer to the patient information leaflet included with Mounjaro for further details and call 111 for a doctor’s advice if you experience these.

Who should not take Mounjaro?

Mounjaro is generally suitable for most people. However, it should not be taken by those:

  • Under the age of 18
  • Who are pregnant or planning to become pregnant
  • With diabetic eye disease
  • With medullary thyroid carcinoma (MTC) or with family members who have it
  • With multiple endocrine neoplasia syndrome type 2 (MEN 2)
  • Who have had pancreatitis
  • Who have problems with their digestive system
  • Who have had kidney problems
  • Who have had a serious allergic reaction to tirzepatide or any other ingredients in Mounjaro

This list is not exhaustive. If you have any health conditions or are taking any medication which could potentially interfere with using Mounjaro, you should refer to your physician for advice before taking it

How can I buy Mounjaro at Pharmacy Prime?

Mounjaro is a POM (prescription-only medication). As a result, Mounjaro and other similar weight loss injections are not available to freely buy. At Pharmacy Prime, you can potentially receive Mounjaro by registering for our weight management service. First, you will need to fill in some questions about your weight and other medical details. One of our pharmacists will then review this information and prescribe you the appropriate medication.

Through this service, you will be provided the relevant medication for you as chosen by one of our pharmacists. You could be prescribed Mounjaro, though the medication prescribed differs from person to person, depending on their unique circumstances.

Contact us

We hope this guide on Mounjaro has helped you learn in-depth about how Mounjaro works and help you assess if it’s suitable for you. If you would like to know more about the different medications we provide at Pharmacy Prime or have any other enquiries relating to our products, please get in touch with us. A member of our friendly team will be in touch to provide you with assistance.