weight loss
What is Mounjaro?
Mounjaro (tirzepatide) is a once-weekly self-injection designed to support weight loss and help with weight management. It works by reducing cravings, lowering your appetite, and helping you feel fuller for longer, even when you’re eating less.
The main ingredient in Mounjaro injections is tirzepatide. It works on two natural hormones in the body: GLP-1 (glucagon-like peptide-1) and GIP (glucose-dependent insulinotropic polypeptide). Most weight loss injections only work on GLP-1, but Mounjaro is different because it works on both. This makes it a “dual agonist” treatment, and research shows it can lead to more weight loss than other options.
Through multiple clinical trials, Mounjaro has been proven safe and effective for long-term use in the UK, and is only available on prescription through licensed providers like Chemist4U.
“Mounjaro works best when paired with lifestyle changes, like eating a balanced diet, staying active, and building healthy habits you can stick with. Combining these with your treatment plan gives you the best chance of seeing results and reaching your weight loss goals safely. At the end of the day, healthy habits support weight loss and help you maintain it for the long term.”
– Jason Murphy, Head Pharmacist
Who manufactures Mounjaro?
Mounjaro injections is manufactured by Eli Lilly, a pharmaceutical company founded in 1876. For over 145 years, they’ve been trusted to produce medication for diabetes, mental health, cancer, and, more recently, weight loss. In 2022, they launched Mounjaro. Today, their treatments are used by millions of people in more than 100 countries.
How does Mounjaro work?
Mounjaro injections works in three key ways:
- Reducing appetite: Mounjaro works on two hormone receptors (GLP-1 and GIP) to signal your brain that you’re full. This helps curb cravings, control portion sizes, and make following a weight loss plan easier.
- Slowing digestion: By slowing how quickly food leaves your stomach, Mounjaro keeps you feeling satisfied for longer, helping you avoid unnecessary snacking and stay on track with healthier eating habits.
- Regulating blood sugar: Mounjaro improves insulin response and helps stabilise blood sugar levels, reducing hunger spikes.
All of this helps you stay in a calorie deficit when following an appropriate diet, which is the key to effective and sustainable weight loss. A calorie deficit happens when you consume fewer calories than your body burns, encouraging your body to use stored fat for energy. This leads to weight loss and is considered the cornerstone of most weight loss programs.
How long does it take to work?
Mounjaro injections starts working from your very first dose, helping reduce your appetite and cravings immediately, and most people notice a real difference within their first week. During this time, you may find that:
- Your appetite feels reduced
- Cravings become easier to manage
- You feel fuller for longer, even with smaller portions
It can take a little longer for some people, who may not experience the full effects for a few weeks.
While Mounjaro starts working immediately, you might not see huge movement on the scales in your first month. More noticeable changes in your weight and appearance happen as you continue treatment.
How effective are Mounjaro injections?
Mounjaro is highly effective in supporting weight loss. Clinical studies have found that patients taking Mounjaro achieved an average weight loss of around 22.5% of their body weight over 72 weeks. However, results can vary from person to person.
Factors like your starting weight, commitment to your diet and exercise plan, and any underlying health conditions can all influence your progress. What matters most is that you’re taking positive steps to improve your health.
Mounjaro in clinical studies
Mounjaro has undergone rigorous clinical trials, the largest of which were the SURMOUNT trials. These trials tested Mounjaro’s efficacy on thousands of people through randomised, placebo-controlled studies.
The trials and results
| Trial | Duration & size | Highest average weight loss | Common side effects | Key takeaway |
| SURMOUNT-1 | 72 weeks, 2,539 people | –22.5%(15 mg) | Nausea, diarrhoea, constipation | Up to 57% lost ≥20% of body weight. |
| SURMOUNT-2 | 72 weeks, 938 people | –14.7%(15 mg) | Nausea, diarrhoea, vomiting | Strong results in people with type 2 diabetes. |
| SURMOUNT-3 | 72 weeks, 806 people | –21.1%(after lifestyle run-in) | Nausea, diarrhoea, constipation | Effective even after a diet and exercise program. |
| SURMOUNT-4 | 36 weeks open-label + 52 weeks randomized, ~700 people | –21%(first 36 weeks) | Nausea, diarrhoea, vomiting | Tested weight maintenance. Patients who stayed on Mounjaro kept weight off. Those who stopped regained much of it. |
Key Takeaways
- Across each trial, Mounjaro led to 15–22.5% average weight loss.
- Most patients (80–90%) achieved at least 5% weight loss.
- Many reached 20% or more, similar to results from bariatric surgery.
- Side effects were mostly mild stomach issues like nausea and diarrhoea.
- SURMOUNT-4 proved long-term benefits: continuing Mounjaro helps keep weight off, while stopping can lead to weight regain.
- Always read the patient information leaflet before use
In summary, these trials showed Mounjaro to be highly effective in weight loss with only mild side effects.
Is Mounjaro right for me?
To find out if Mounjaro (tirzepatide) is right for you, you’ll need to complete an online consultation. Here, you’ll answer a few short questions about your health so a clinician can check whether it’s right for you before prescribing.
Whether Mounjaro is right for you depends on your current weight, health conditions, medications, and medical history. Your clinician will take all of this into account before prescribing. If it’s not right for you, they’ll work with you to find a suitable alternative treatment and provide advice if you’re concerned about your health and weight.
Mounjaro doses
Mounjaro comes prefilled in a ‘kwikpen’ in different dose strengths. You’ll gradually increase your dose over time. The Mounjaro Kwikpen makes controlling your doses straightforward, as you don’t need to fill them yourself.
You’ll usually start on 2.5mg and work your way up to a maintenance dose, which can be up to 15mg. This step-by-step process is called ‘titration’. It allows your body to adjust slowly, helping to reduce side effects and keep you safe.
Your maintenance dose is the highest dose of Mounjaro you’ll take, as it’s designed to support the best long-term weight loss for you. For some people, this may be lower than 15mg. Your prescriber will work with you to find the right dose for you.
Mounjaro dosing schedule
A typical Mounjaro dosing schedule looks like this:
| Weeks | Dose | How often | What this means |
| 1–4 | 2.5 mg | Once a week | This is your starting dose. It helps your body get used to Mounjaro. |
| 5–8 | 5 mg | Once a week | Your first increase, most people tolerate this well. |
| 9–12 | 7.5 mg | Once a week | Gradually increasing to boost results. |
| 13–16 | 10 mg | Once a week | By now, many people notice steady weight loss. |
| 17–20 | 12.5 mg | Once a week | Higher dose if needed for extra support. |
| 21 onwards | 15 mg | Once a week | This is the maximum maintenance dose. Not everyone needs to go this high. Your prescriber will decide what’s right for you. |
Your dosing schedule might vary depending on how you respond to treatment or whether you experience any side effects. If you’re concerned about getting your doses right or how to use your Mounjaro kwikpen, you can reach out to our prescribers at any time.
Weight loss week by week
While everyone’s weight loss journey is different, here’s what you could expect from your first 6 months and beyond on Mounjaro.
Weeks one to four – Getting started
Dose: 2.5mg
- Your body is adjusting to the medication, so you may notice mild side effects.
- Appetite and cravings may start to reduce, but significant weight loss is unlikely at this stage.
Weeks four to eight – Appetite control
Dose: 5mg
- Many people begin noticing fewer cravings, feeling fuller for longer, and finding it easier to manage portion sizes.
- Energy levels improve as your eating habits become more balanced.
Months three to six – Visible results
Dose: Increased gradually up to 15mg.
- You have much better appetite control, making it easier to stick to healthy routines and manage “food noise.”
- Most people notice steady, visible weight loss by this stage — typically 9–11% of body weight by month six.*
Six months+ – Long-term progress
Dose: Maintained at 15mg (or your chosen maintenance dose)
- By now, most people feel more in control of their eating habits and have better daily energy levels.
- With healthy lifestyle changes, patients can lose an average of 22.5% of their starting weight after 18 months.
*Results vary between individuals.
Why do you have to increase your dose of Mounjaro?
You need to gradually increase your dose of Mounjaro to give your body time to adjust to the medication. This step is important for your safety, as it helps reduce side effects and ensures your body is responding well to treatment.
You’ll order your next Mounjaro pens at a new dose each month while titrating until you reach a ‘maintenance’ dose.
Do I need to start from the lowest dose of Mounjaro?
Yes. If you’re new to Mounjaro, you need to start from the lowest dose and request the 2.5mg Mounjaro pen. This is to make sure you respond well to the medication and to help reduce side effects.
What happens if I miss a dose?
If you’ve forgotten or missed a dose, what you should do depends on how much time has passed since you were meant to take it.
- If it’s been less than four days, take the dose and continue treatment as normal.
- If it’s been more than four days, skip the dose and take your next dose on your regular day.
- If it’s been more than two weeks, speak to your prescriber. You may need to restart or adjust your treatment plan.
Never take more than one dose at once to make up for missing a dose.
When should I order my next dose?
If you’re increasing your dose, we recommend waiting until your third injection before ordering your next dose. This is to ensure that you’re tolerating your current dose before increasing.
While you can order three weeks in advance, if you were to develop side effects during that time, you might not be able to move up to your new dose.
It’s also important to remember to keep any unopened injections you order early in the fridge until you’re ready to take them.
Mounjaro eligibility
Mounjaro for weight loss is suitable for people who are medically obese or overweight with weight-related health issues and are looking to lose weight. This means having a BMI over 30, or a BMI over 27 with a condition like high cholesterol, high blood pressure, or type 2 diabetes.
Check if you might be eligible for Mounjaro for weight loss with our BMI calculator.
How to buy Mounjaro:
You can only buy Mounjaro if it’s been approved for you by a clinician and they’ve issued a prescription. You can do this by requesting treatment with us. All you need to do is complete a short consultation for our clinicians to review, and if suitable, you’ll be able to buy Mounjaro with fast and discreet home delivery.
Never attempt to buy Mounjaro from an unlicensed seller, as you could end up with fake or dangerous medication. Always use trusted providers who are approved by the GPhC and MHRA, like us.
How do I get a prescription for Mounjaro?
You can get a prescription for Mounjaro privately through a trusted, regulated provider like Chemist4U. All you need to do is complete a short online consultation so a prescriber can check your eligibility and make sure it’s safe for you. If you’re eligible and they’ve reviewed your health, they’ll issue a prescription.
Can you get Mounjaro on the NHS?
Yes, you can get Mounjaro on the NHS, but the criteria are much stricter, making it more challenging to access than using a private service.
Their criterion is that you must have a BMI of 40 or more (or 37.5 and above for certain ethnic groups) and at least four weight-related health conditions, such as type 2 diabetes, high blood pressure, heart disease, or sleep apnoea.
In addition, it can only be prescribed through specialist weight management services, which are currently being rolled out in phases across the UK.
Will my GP be informed if I start Mounjaro with Wellnesstabs
Yes. When you start treatment, a letter is issued to inform your GP that you have been issued a prescription for Mounjaro. This is to keep any other healthcare professionals involved in your care, and informed of your current medication.
