What is Mounjaro and what does it do for rapid weight loss?

Weight loss is something many people try at some point in their lives. Whether it’s for physical health reasons or to improve their mental health and body image, over 40% of Britons actively engage in weight management through dieting and exercise.^[1] However, for some individuals, losing weight is a much greater challenge. Genetics, hormonal imbalances and health conditions can all hinder the process, leaving individuals searching for an alternative. 

In this comprehensive analysis, we explore the prescription weight loss treatment, Mounjaro, how it works, and how to take it. We will also discuss the benefits and side effects of the medication, as well as answering some common questions into this weight loss drug.

What is Mounjaro?

Mounjaro is a prescription medication that facilitates rapid weight loss. It was approved by the Medicines and Healthcare products Regulatory Agency (MHRA) in November 2023 and is designed to help adults living with obesity and related health issues to manage their weight effectively. 

Mounjaro contains tirzepatide, an ingredient that influences appetite and improves insulin regulation, helping individuals to feel full and assisting with the control of blood sugar levels. This leads to decreased food intake and supports the loss of fat tissue. When combined with lifestyle changes, it can result in substantial and sustained improvements to weight.

How to take Mounjaro

Mounjaro is injected under the skin. It comes in a pen with pre-filled doses that patients can administer themselves. It should be taken exactly as your Prescriber recommends - typically once a week on the same day and at the same time. It can be injected into the abdomen or upper leg; as with other weight loss injections, you should change the injection site each week to prevent soreness. 

The starting dose for all patients is 2.5mg once a week for four weeks. This will then increase to 5mg once a week. Depending on your needs and progress the dose will then be increased at four-week intervals as your clinician recommends. Doses come in 2.5mg, 5mg, 7.5mg, 10mg, 12.5mg and 15mg amounts.^[2]

Mounjaro begins to work within hours of entering your body, taking between 8-72 hours to reach peak levels. It has a half-life of five days (a half-life is the amount of time it takes for your body to get rid of half a dose), which is why it should be injected no more than once a week.^[3] If you stop using it, your body will be free of it in around 30 days. It is most effective when combined with lifestyle changes.

Mounjaro is considered safe to use for as long as your doctor or clinician prescribes it. NICE recommends taking it for a maximum of two years, which for many people is plenty of time to reach their goal weight. Whether you take it beyond this point will depend on your preferences and the recommendations of your healthcare professional.

How does Mounjaro work?

Mounjaro’s key ingredient is tirzepatide, which activates receptors in the stomach and brain to stimulate a feeling of satiety. As a result, individuals using Mounjaro will feel satisfied after smaller meals and consume fewer calories overall, helping them to lose weight. The dosage is usually increased over time until the weight loss goal has been achieved. In a 2022 study, participants lost up to 20.9% of their weight over a period of 72 weeks.^[4]

Mounjaro also improves the body’s sensitivity to insulin, which controls blood sugar levels. After eating, insulin removes excess glucose from the bloodstream and stores it in the cells for later use. In many individuals facing obesity, their cells don’t respond to insulin as they should, causing a build up of glucose in the blood. This can lead to carb cravings, low energy and increased hunger.

Mounjaro increases the responsiveness of cells in the fat tissue, liver and muscle to insulin, which helps to regulate blood sugar and curb cravings. 

Who can take Mounjaro?

Mounjaro has been tested and approved for use by adults over the age of 18, who are struggling with obesity and weight related health problems. As a relatively new medication, its use should be supervised by a GP or other healthcare professional with the relevant qualifications. 

In studies, Mounjaro was given to patients with a BMI of over 30, or a BMI of over 27 if they also had at least one weight-related health issue, such as type 2 diabetes or high blood pressure. You may be recommended it if you fit a similar profile and have struggled to lose weight through changes to diet and lifestyle. 

Those with certain digestive issues or who are taking other medications may need adjusted dosing or additional supervision. If, for example, you have thyroid issues or are using blood thinners, you will need to highlight this with your GP. Women using oral contraceptives should consider using a barrier method of contraception or switching to non-oral contraception while taking Mounjaro.

Benefits of taking Mounjaro

Comprehensive studies have shown that there are many potential benefits to taking Mounjaro. These include: 

●        Effective weight management: Two international clinical trials and several additional studies have shown that Mounjaro is an effective rapid weight loss and weight management treatment. In trials, patients experienced a loss of up to 22.5% of their weight, with 96.3% of patients losing at least 5% of their body weight compared to 27.9% of those taking the placebo. 

●        More stable blood sugar levels: In five main studies involving over 6,000 adults with type 2 diabetes, Mounjaro was found to effectively control blood sugar levels, lowering overall blood glucose levels 40-52 weeks of use.^[5] 

●        Reduced need for diabetes medications: Mounjaro’s effect on natural insulin sensitivity may result in less need for insulin shots or other diabetes medications. 

●        Reduced LDL cholesterol and blood pressure: Losing just 10% of excess body weight reduces the amount of ‘bad’ LDL cholesterol in your system and has a positive impact on blood pressure.^[6] 

●        Increased energy and reduced fatigue: Inflammation associated with obesity is linked with feelings of fatigue. As Mounjaro facilitates weight loss, energy levels rebalance. Exercise becomes easier, also boosting energy. 

●        Improved mobility: Knee and back pain caused by excess body weight often decreases as weight is lost, improving mobility and making exercise easier. 

Possible side effects of taking Mounjaro

As with any medication that is aimed at altering body functions, Mounjaro may cause some adverse side effects. The most common associated with tirzepatide include nausea, which about 20% of users in research trials experienced; diarrhoea, which was reported by approximately 16% of users during clinical trials; and vomiting, which was reported by around 9% of users.

Approximately 7% of users reported abdominal pain or discomfort during clinical trials, while around 2.4% experienced constipation. All of these symptoms are usually mild, but if they seem severe or do not improve in time, contact your GP or prescriber. 

In rare cases, more serious side effects can develop with long term use. These include liver dysfunction, pancreatitis, mood changes, acute kidney damage and thyroid cancer. It is therefore of vital importance that Mounjaro is only taken with the supervision of a GP or clinician, and that patients follow the proper dosage instructions and monitor their side effects. 

Taking Mounjaro safely and effectively

Mounjaro is intended for use as part of a broader weight management programme, which includes diet and lifestyle adjustments. Individuals using it will achieve the best results when combining Mounjaro with a balanced diet that includes plenty of fruit and vegetables and reduced sugar. Regular exercise should also be undertaken as part of the strategy.

Although a rapid weight loss drug, Mounjaro is not a ‘magic pill’ and will not enable you to achieve your goal weight in a matter of weeks. Rather, it is designed to facilitate small and consistent changes that will lead to long term outcomes. By pairing the doses with lifestyle changes, it can help you form new and healthier habits that will enable you to sustainably manage your weight even after you stop taking the medication. 

While some people may see their weight begin to drop within the first few weeks of using Mounjaro, most people will experience more gradual changes. One study found that, during the first four weeks of use, participants lost less than 1% of their starting body weight each week.^[7] You will more likely begin to notice the weight loss at around 8-12 weeks. A Phase 3 study showed that after 8-12 weeks, individuals using the drug lost 6-8% of their body weight on average, using doses of 5-15mg per week.

Long term studies of 40-52 weeks showed weight loss in participating adults ranged from 5.5kg to 11.4kg. Generally speaking, the higher the dose, the greater the weight loss. 

You must never adjust dosage without the approval of your prescriber. 

Take the next step with The Happy Pharmacy

At The Happy Pharmacy, we aim to make healthcare accessible, convenient and tailored to your needs. Our team is here to provide high-quality medications as well as the support and advice you need.

If you are looking to lose weight with the help of Mounjaro, our licensed UK clinicians can help. You can get started by taking our quick, secure online medical consultation. We’ll then review it and, if the medication is deemed safe and suitable for you, we will  deliver it discreetly in unbranded, secure packaging. You can also access ongoing support, including check-ins, dosage adjustments and lifestyle guidance whenever you require it.

Start your journey towards a healthier body today.

FAQs

Can I take Mounjaro if I’m not diabetic?

Yes, Mounjaro can be prescribed for individuals who are struggling with weight management. However, patients must fit the criteria - including health profile and BMI - to be eligible for its use.

What should I do if I miss a dose?

If you miss a dose of Mounjaro, take the missed dose as soon as you remember to. However, if it has been more than four days since the missed dose, skip it and continue taking your regular dose on the usual day. Do not inject two doses within three days of each other. 

How should I store Mounjaro?

Your Mounjaro doses should be stored in the refrigerator at between 2 and 8°C before use. Do not freeze or use if frozen. Once the first dose of your KwikPen has been administered, store the pen at room temperature, out of direct sunlight and away from heat sources. Your doses must be used within 30 days and the pen should be kept in its original packaging.

If stored below 2°C or above 30°C, Mounjaro can become unsafe and should be discarded. 

What’s the difference between Mounjaro and Ozempic?

While both weight loss injections, Mounjaro and Ozempic contain different active ingredients. In Mounjaro the active ingredient is tirzepatide, while Ozempic contains semaglutide.

Can I drink alcohol on Mounjaro?

Although alcohol does not directly interact with the tirzepatide in Mounjaro, drinking alcohol while taking it is not recommended. This is because alcohol may heighten the risk of experiencing side effects and impacting factors like blood sugar levels.

How can I sustain weight loss after stopping Mounjaro?

When stopping Mounjaro, you will optimise your chances of maintaining your goal weight by adhering to a healthy diet plan that includes plenty of fruit and vegetables, taking regular exercise and taking care of your mental and emotional wellbeing. Research shows that around 40% of people increase their food intake when stressed, so managing your stress levels can help you maintain your goal weight.^[8]