Mounjaro Injection
Mounjaro weight loss injections (Tirzepatide) are the UK’s most effective prescription weight loss injection, clinically proven to help you lose up to 22% of your starting weight. It works by mimicking two hunger-relating hormones (GLP-1 and GIP) this means fewer cravings, smaller appetite and sustainable results.
You can buy Mounjaro through our GPhC-registered online pharmacy with free clinical support throughout your treatment.
Every weight loss treatment with The Family Chemist includes free access to online nutrition coaching powered by Nutrable. After your purchase is approved, you’ll receive your access code by email. You can also find your access code in your Family Chemist dashboard.
Prices starting from:
£164.99
Mounjaro Price
Mounjaro cost in the UK varies by dose. At The Family Chemist, we strive to offer our customers affordable private care, we regularly check our prices against competitors to ensure you’re getting the best value for money.
What is Mounjaro?
Mounjaro is a once-weekly injection that supports weight loss and aids weight management. It works by reducing food cravings and appetite, helping you feel fuller for longer.
The main ingredient in Mounjaro injections is Tirzepatide. It works by mimicking the action of two hormones (GLP-1 & GIP) that target areas of the brain involved in appetite regulation.
Clinical trials show that Mounjaro weight loss injections can reduce bodyweight by up to ~22% making it a highly effective option for weight loss. It is only available on prescription in the UK through licensed providers like The Family Chemist.
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“Every consultation is reviewed carefully to ensure treatment is safe, appropriate, and tailored to the individual. Patient wellbeing is always our priority.”
Sunny Dhain – Clinical Director | MRPharmS | PGDip | GPhC registered pharmacist
How do Mounjaro weight loss injections work?
Mounjaro contains the active ingredient tirzepatide, it works by targeting two receptors in the body called GIP and GLP-1. These two receptors help regulate appetite, blood sugar levels and how the body uses energy.
By activating both receptors, Mounjaro can help you feel fuller for longer, reduce food cravings and support weight loss alongside healthy lifestyle changes.
The GLP-1 receptor helps lower appetite and supports blood sugar control. The GIP receptor also plays a role in appetite, energy balance and how the body stores and uses fat.
Because Mounjaro targets both receptors at the same time, it may support greater weight loss than treatments that only target GLP-1 receptors.
All of this means that Mounjaro helps reduce hunger, supports better appetite control and makes it easier to manage your food intake as part of a weight loss plan.
How effective is Mounjaro?
- 5mg injection – 15.0% average weight lost
- 10mg injection – 19.5% average weight lost
- 15mg injection – 20.9% average weight lost
- Placebo saw a 3.1% average of weight lost.
Who can take Mounjaro?
Mounjaro injections are suitable for adults who meet specific clinical criteria and can safely use it under medical guidance. You may be eligible for Mounjaro treatment if you meet one of the following:
Have a BMI of 30 kg/m² or above (clinically obese)
Have a BMI of 27–30 kg/m² (overweight) with a weight-related condition such as high blood pressure, high cholesterol, pre-diabetes, or heart disease
Are from an ethnic background, where lower BMI thresholds may apply (typically from 27.5 kg/m²) due to increased metabolic risk
Are transferring from another provider and wish to continue injecting Mounjaro with our service
To find out if you can use Mounjaro injections, you’ll need to complete an online consultation to check your eligibility before prescribing.
Whether you’re eligible for Mounjaro will depend on factors including your current weight, health conditions, medications and medical history.
Can you get Mounjaro on the NHS?
Yes, Mounjaro weight loss injections are available on the NHS for some patients, but access is currently limited due to stricter criteria.
Not all GP practices prescribe the Mounjaro weight loss injection, as availability depends on local NHS services and strict eligibility criteria.
The NHS rollout is being introduced over a phased period over several years, with priority given to patients with the highest medical need. As a result, many people may not yet qualify and may need to consider private treatment options if they want to start Mounjaro injections sooner.
Who Is Eligible for Mounjaro on the NHS?
To qualify for Mounjaro during the initial rollout, you must have:
- A BMI of 40 or above, and
- At least four of the following conditions:
- High blood pressure
- High cholesterol or abnormal blood fats
- Obstructive sleep apnoea
- Heart or cardiovascular disease
- Type 2 diabetes
Has Mounjaro been clinically tested?
The SURMOUNT-1 trial provides strong evidence for Mounjaro’s effectiveness in weight management. In this study, adults with obesity or who were overweight but did not have diabetes, experienced significant weight loss when using tirzepatide.
The results showed that Mounjaro weight loss injections can support meaningful weight reduction in eligible patients when used alongside diet and lifestyle changes. The trial also helped demonstrate its safety profile, although Mounjaro may not be suitable for everyone and should only be used following clinical assessment.
How long does Mounjaro take to work?
Most patients begin to notice early weight changes within the first 2–4 weeks of starting Mounjaro weight loss injections, with more significant weight loss results developing over 8–12 weeks as the dose is gradually increased.
Average weight loss on different Mounjaro doses
Key points about Mounjaro weight loss injection results:
Early effects (2–4 weeks): Reduced appetite and improved portion control after starting the Mounjaro pen.
Progressive weight loss (8–12 weeks): Visible fat loss as the dose is titrated safely.
Maximum results (up to 72 weeks): Clinical studies show up to 22.5% body weight loss on the highest dose when injecting Mounjaro alongside lifestyle changes.
Dose escalation matters: Gradual increases help minimise side effects and improve long-term results.
Best outcomes: Achieved when Mounjaro injections are combined with a balanced diet and at least 150 minutes of weekly physical activity.
Additional benefits: Improvements in waist circumference, blood pressure, cholesterol levels, and insulin sensitivity.
How do I use Mounjaro weight loss injections?
Mounjaro is available in multiple dosages: 2.5mg, 5 mg, 7.5 mg, 10 mg, 12.5 mg, and 15 mg solutions for injection, each supplied in one pre-filled pen designed for easy use.
Before using Mounjaro, always read the instructions for use and the package leaflet provided with your pen for the latest information and guidance.
- Initial Phase: Start with 2.5 mg once weekly for the first four weeks.
- Titration: Increase the dose in 2.5 mg increments every 4 weeks as advised, up to a maintenance dose of 5 mg, 10 mg, or 15 mg weekly, depending on tolerance and response.
Concerned about giving yourself an injection?
“Many patients feel anxious about the idea of self-injecting at first. However, Mounjaro is designed to make the process as straightforward and comfortable as possible. It is supplied in a pre-filled pen device rather than a traditional syringe, making administration simple and controlled. The needle used is very fine and significantly smaller than those typically used for routine injections, and the pen mechanism delivers the dose, without the need for manual pressure.”
– Sunny Dhain MPharm, PGDip Independent Prescriber, Clinical Director
How to use Mounjaro injections
We have detailed step-by-step instructions on how to use Mounjaro pens:
- Timing: Administer Mounjaro once a week, ideally on the same day and time, to maintain steady medication levels.
- Injection Sites: Inject into the abdomen, upper thighs, or outer section of the upper arms. Avoid veins and muscles. Rotate injection sites within these areas to reduce irritation.
- Preparation: Use a new BD viva pen needle for each injection. Inspect your pen and needle for damage and ensure the medication is clear and colourless to slightly yellowish.
- Dosing Schedule: Begin with a 2.5 mg dose once a week for 4 weeks, then increase the dose as directed, following a titration schedule to optimise efficacy and minimise side effects.
What are the alternatives to Mounjaro?
Weight Loss Treatment Comparison
Several alternatives to Mounjaro are available for weight management, each using different active ingredients and mechanisms to support weight loss. The options below are commonly prescribed in the UK: To explore weight-loss treatments, visit our weight loss injections page and begin your medically supervised weight-management journey with guidance from our prescribing team.| Mounjaro | Wegovy | Liraglutide | Wegovy Tablets | Xenical | Orlistat | Alli | Mysimba | |
| Category | Injection | Injection | Injection | Tablet | Tablet | Tablet | Tablet | Tablet |
| Active Ingredient(s) | Tirzepatide | Semaglutide | Liraglutide | Semaglutide | Orlistat | Orlistat | Orlistat | Bupropion and Naltrexone hydrochloride |
| Mode of Action | GLP-1 receptor agonist and GIP mimetic | GLP-1 receptor agonist | GLP-1 receptor agonist | GLP-1 receptor agonist | Lipase inhibitor | Lipase inhibitor | Lipase inhibitor | Multimodal action |
| Administration | Once weekly | Once weekly | Once daily | Once daily | With meals | With meals | With meals | With meals |
| Dosage | Starting at 2.5mg, up to 15mg | Starting at 0.25mg up to 7.2mg | Starting at 0.6mg up to 3mg | Starting at 1.5mg up to 25mg | One up to three times a day | One up to three times a day | 60mg up to three times a day | One to four tablets a day |
| Weight Loss % | Up to 21% to 22.5% | About 21% | About 5% to 10% | About 14% to 20% | About 5% to 10% | About 5% to 10% | About 5% | About 5% to 10% |
| Common Side Effects | Nausea, indigestion, diarrhoea, vomiting, constipation, stomach pain | Nausea, indigestion, diarrhoea, vomiting, constipation, stomach pain | Nausea, hypoglycaemia, diarrhoea, constipation, headache, decreased appetite | Nausea, indigestion, diarrhoea, vomiting, constipation, stomach pain | Oily spotting, gas with discharge, faecal urgency, fatty/oily stool | Similar to Xenical: Oily spotting, gas, faecal urgency | Similar to Xenical but may be milder due to lower dose | Nausea, constipation, headache, dry mouth, dizziness |
| Manufacturer | Eli Lilly | Novo Nordisk | Generic | Novo Nordisk | Haleon | Generic | Not specified | Not specified |
Troubleshooting a Mounjaro Pen
- Air Bubbles: Normal in the pen and do not affect the dose.
- Room Temperature: There’s no need to warm the pen before use.
- Post-Injection Leakage: A drop of liquid or blood on the skin post-injection is normal. Apply gentle pressure with a cotton ball or gauze without rubbing the site.
How to dispose used Mounjaro?
- Each pen should be disposed of properly in a sharps bin after administration.
- Always use a new needle for each injection to prevent infection and ensure sterility.
Monitoring and Adjustments
- Monitor your body’s response to Mounjaro. Adjustments to the dosage may be necessary based on effectiveness and side effects.
- If adding Mounjaro to other diabetes medications like sulphonylureas or insulin, monitoring and dose adjustments may be needed to reduce the risk of hypoglycemia.
Who cannot use Mounjaro?
You cannot use Mounjaro if you:
- Are pregnant or planning pregnancy
- Are breastfeeding
- Are over 75 years old
- Have severe stomach or gut conditions such as severe gastroparesis (where the stomach empties too slowly)
- Have certain types of diabetic retinopathy (an eye condition related to diabetes)
- Have been diagnosed with acute pancreatitis
Use Mounjaro with caution if you:
Have a history of pancreatitis
Mounjaro has not been widely studied in patients with previous pancreatitis. Stop treatment immediately and seek medical help if you develop severe stomach pain, nausea, or vomiting.
Take diabetes medication
Using Mounjaro alongside diabetes medication such as insulin or sulphonylurea medicines can increase the risk of low blood sugar (hypoglycaemia). Your prescriber may need to adjust your dose and monitor you closely.
Experience severe gastrointestinal side effects
Common side effects such as nausea, vomiting, or diarrhoea can lead to dehydration, which may affect kidney function — particularly in older adults. Staying well hydrated is important.
Take other oral medications
Mounjaro can slow stomach emptying and affect how some oral medicines are absorbed, especially medicines where the dose needs to be very precise to work safely. Your prescriber may review your medication regimen.
Mounjaro side effects
What are the most common side effects of Mounjaro?
- Diarrhea
- Nausea
- Vomiting
- Constipation
- Low blood sugar – particularly when taken with certain diabetes medications.
Can Mounjaro Cause Low Blood Sugar?
- Shaking
- Sweating
- Dizziness
- Hunger
- Rapid heartbeat.
It’s important to inform your doctor if you experience these symptoms.
Other common side effects of Mounjaro
- Faster pulse
- Allergic skin reactions such as rash, itching or eczema
- Stomach pain
- Indigestion
- Bloating
- Burping or wind
- Heartburn or acid reflux
- Feeling tired
- Low blood pressure
- Hair loss
- Irritation, itching or redness where the injection was taken
- Changes in blood test results – increased pancreatic enzymes
Uncommon side effects of Mounjaro
What are the long-term side effects of Mounjaro?
What should I do if I experience serious side effects from Mounjaro?
- Pancreatitis
- Allergic reactions
- Gallbladder problems
If you experience any symptoms of these such as breathing difficulties, swelling of the throat, face, and mouth, fainting, severe stomach and back pain, then stop taking Mounjaro and seek medical help immediately.
This is not a full list of possible side effects. Always read the patient information leaflet before using Mounjaro so you understand the possible side effects, warnings and precautions and if you experience side effects not listed above, complete a MHRA Yellow Card report.
What is the difference between Mounjaro and Wegovy?
Mounjaro and Wegovy are both weekly weight-loss injections that help reduce appetite, make you feel fuller and support long-term weight loss. The main difference is the active ingredient used and how they work in the body.
Mounjaro contains Tirzepatide, which targets two hormones (GLP-1 and GIP). These hormones help control appetite, fullness and blood sugar levels.
Wegovy contains Semaglutide, this only targets the GLP-1 hormone which helps to reduce hunger and make you feel fuller for longer.
Both weight loss injections are effective but the right option depends on your weight-loss goals, and how well you tolerate the treatment. Our clinicians will help you decide which treatment is most suitable for you.
Does Mounjaro affect the contraceptive pill?
Yes, Mounjaro can make the contraceptive pill less effective for a short time. This is important when you first start taking Mounjaro injections and after increasing each dose.
It’s recommended that patients using oral contraceptives to use a barrier method such as condoms while on Mounjaro, or explore alternative contraceptive methods that are not taken orally.
This precaution should be observed for a duration of 4 weeks upon initiating Mounjaro treatment, as well as for 4 weeks following any dosage adjustments of Mounjaro.
Mounjaro treatment starts at 2.5mg once a week. You will usually stay on this dose for the first 4 weeks. This gives your body time to adjust and may help reduce early side effects.
After 4 weeks our clinician may increase your dose to 5mg once a week. If you need more support and are tolerating the treatment well, your dose may then be increased gradually by 2.5mg at a time. You will usually stay on each dose for at least 4 weeks before moving up.
The highest approved adult dose is 15mg once a week. The UK patient leaflet and EMA product information both describe this step-up dosing schedule.
You should only increase your dose when advised to. Increasing your dose too quickly or taking more than prescribed can increase the chance of side effects such as feeling sick, stomach discomfort, dehydration, and tiredness.
Not everyone needs to reach the highest dose. Some people get good results on a lower or middle dose and prefer to stay there, especially if it helps them manage side effects. Higher doses may provide more appetite control for some people, but they may also increase the chance of side effects and cost more.
What is the Mounjaro maintenance dose?
A Mounjaro maintenance dose is the dose you stay on long term to help maintain the weight you’ve lost.
The recommended maintenance doses are usually 5mg, 10mg or 15mg once a week. The right dose can vary from person to person and will depend on your progress, side effects and how well you tolerate the treatment.
Not everyone needs to reach the highest dose. Many people stay on the dose that gives them steady results while keeping side effects manageable.
Our clinicians will help decide which maintenance dose is most suitable for you.
How to buy Mounjaro online in the UK
You can buy Mounjaro online if it’s been approved for you by a clinician and they’ve issued a prescription, you can do this by completing a consultation assessment with The Family Chemist.
This asks about your health, current medication, current weight and your weight loss goals.
Before treatment is approved, we check that it is safe and suitable for you.
One of our prescribers will review your consultation to decide whether Mounjaro injections are suitable for you.
You can also log into your online account to track your progress and message one of our clinicians for support while using Mounjaro.
Where should I get my Mounjaro injections from?
You should only get Mounjaro from a regulated UK pharmacy or approved healthcare provider like The Family Chemist.
At The Family Chemist your consultation is reviewed by a qualified prescriber. If Mounjaro is approved, you will have access to clear guidance and ongoing support throughout your treatment.
When you start treatment with The Family Chemist, you will also receive access to a complimentary support programme created by our in-house nutritionists and clinicians. This includes practical advice on healthy eating, physical activity and building sustainable habits alongside your medication.
You will also receive simple trackers and goal-setting tools to help you stay organised, monitor your progress and keep your weight loss plan on track.
If you have any questions during treatment, our clinical team is here to provide clear and reliable support.
Start your weight-loss journey with confidence
Starting treatment with The Family Chemist is simple, secure and guided by our clinical team.
Complete a short online medical questionnaire
Our prescribers review your information to check if treatment is suitable
Receive personalised next steps and access to your free support package
Request your treatment securely online
Take the first step towards a healthier weight with expert support from The Family Chemist. Start your consultation now.
Sources
- Tirzepatide once weekly for the treatment of obesity in people with type 2 diabetes (SURMOUNT-2): a double-blind, randomised, multicentre, placebo-controlled, phase 3 trial (2023) The Lancet [accessed 9th February 2026]
- Tirzepatide Once Weekly for the Treatment of Obesity (2022) The New England Journal of Medicine [accessed 9th February 2026]
- Mounjaro 2.5/5/7.5/10/12.5/15mg KwikPen solution for injection in pre-filled pen (2024) EMC: Patient Information Leaflet [accessed 9th February 2026]
- Wegovy 0.25 mg, FlexTouch solution for injection in pre-filled pen, emc [accessed 9th February 2026]
- A Study of Tirzepatide (LY3298176) in Participants With Type 2 Diabetes Who Have Obesity or Are Overweight (SURMOUNT-2) (2024) Clinical Trials [accessed 9th February 2026]
- A Study of Tirzepatide (LY3298176) In Participants After A Lifestyle Weight Loss Program (SURMOUNT-3) (2024) Clinical Trials [accessed 9th February 2026]
- Continued Treatment With Tirzepatide for Maintenance of Weight Reduction in Adults With Obesity (2024) JAMA [accessed 9th February 2026]
- Mounjaro is the first in a new class for the treatment of type 2. Diabetes (2023) Mounjaro [accessed 9th February 2026]
- How to use Mounjaro (2023) Mounjaro [accessed 9th February 2026]
- MHRA authorised diabetes drug Mounjaro (tirzepatide) for weight management and weight loss (2023) GOV.UK. [accessed 9th February 2026]
- Effectiveness of Dulaglutide in the Real World and in Special Populations of Type 2 Diabetic Patients (2020) NIH [accessed 9th February 2026]
- Lilly’s SURMONT-2 results published in The Lancet show tirzepatide achieve a mean weight reduction of 15.7% at the highest dose (15mg) in adults with obesity or overweight and type 2 diabetes (2023) Eli Lilly [accessed 9th February 2026]
- Tirzepatide for managing overweight and obesity (2024) NICE [accessed 9th February 2026]
- Two-year effects of semaglutide in adults with overweight or obesity: the STEP 5 trial (2022) Nature Medicine [accessed 9th February 2026]
- Once-Weekly Semaglutide in Adults with Overweight or Obesity, The New England Journal of Medicine [accessed 9th February 2026]
Medically
reviewed by
Tannaz Sohrabi (MPharm, PGDip, IP, MRCPharm)
GPhC Number: 2225756
Last reviewed: 17th April 2026
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