Mounjaro Weight Loss Injections

Mounjaro is a prescription only treatment which functions by mimicking the action of hormones that target areas of the brain involved in appetite regulation. By administering a once-weekly injection under the skin, Mounjaro aids in significantly reducing food cravings and promoting feelings of fullness. Clinical trials have demonstrated Mounjaro’s ability to help individuals achieve an impressive ~22% reduction in body weight, marking it as a highly effective option for weight loss.

This life changing treatment is available through our UK-registered online prescribing service, ensuring a convenient and secure route to commence your weight loss journey. After completing a straightforward online assessment with our team of clinicians, eligible individuals can have their prescriptions swiftly processed and delivered in 24 hours. Our dedicated pharmacy team then prepares and dispatches the treatment directly to you, ensuring a seamless transition to a healthier lifestyle.

Mounjaro weight loss injections are suitable for adults who meet specific clinical criteria and can safely use the Mounjaro pen under medical guidance. You may be eligible for Mounjaro weight loss injection 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 a 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 start using the Mounjaro pen, you must not have medical conditions or be taking medications that could interact with treatment. Complete our online assessment to check your eligibility and learn how long you may need to stay on Mounjaro injections.

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. Not all GP practices prescribe the Mounjaro weight loss injection, as availability depends on local NHS services and strict eligibility criteria.

NICE has approved tirzepatide (the active ingredient in the Mounjaro pen) for weight management. 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 injecting Mounjaro sooner.

Who Is Eligible for Mounjaro on the NHS?

To qualify for Mounjaro weight loss injections during the initial rollout, you must have:

• A BMI of 40 or above, and
• At least four of the following conditions:

1. High blood pressure
2. High cholesterol or abnormal blood fats
3. Obstructive sleep apnoea
4. Heart or cardiovascular disease
5. Type 2 diabetes

Mounjaro, containing the active ingredient tirzepatide, is a once-weekly injectable medicine that operates on a novel principle by targeting two key receptors involved in metabolic regulation: the glucagon-like peptide-1 (GLP-1) receptor and the glucose-dependent insulinotropic polypeptide (GIP) receptor.

Tirzepatide’s dual action is at the core of its effectiveness. By acting as an agonist for both GIP and GLP-1 receptors, Mounjaro taps into the body’s own mechanisms for regulating appetite and energy balance. GIP plays a critical role in managing energy balance through its action on brain and adipose tissue receptors, contributing to a regulation of food intake and energy expenditure. The GLP-1 receptor’s involvement in lowering blood sugar levels and appetite regulation further complements this action, leading to a more comprehensive approach to weight management.

Has Mounjaro been clinically tested?

The SURMOUNT-1 trial, among others, has provided compelling evidence of Mounjaro’s efficacy in weight management. Participants without diabetes but with obesity or overweight status experienced significant weight reduction, underscoring the potential of this dual-agonist approach. These trials have not only confirmed the weight loss capabilities of tirzepatide but also highlighted its safety profile, making it a promising option for those eligible.

How does Mounjaro work chemically?

Mounjaro’s molecular mode of action is fascinating. The peptide is engineered from the native GIP sequence to precisely target the GIP and GLP-1 receptors. Its affinity for the GIP receptor is comparable to that of native GIP, while its binding to the GLP-1 receptor, although slightly weaker, is sufficiently potent to activate the receptor’s weight loss mechanisms. This dual receptor activation is thought to synergize, enhancing the weight loss effect beyond what could be achieved through GLP-1 receptor activation alone.

The GIP component is believed to act centrally, augmenting the weight loss induced by GLP-1, while also targeting white adipose tissue to improve lipid storage and prevent dietary lipid spillover. This mechanism is crucial for managing the body’s energy and lipid metabolism, offering a protective effect against the accumulation of excess body fat.

Most patients begin to notice appetite reduction and early weight changes within the first 2–4 weeks of starting Mounjaro weight loss injections, with more significant and sustained 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 weight loss 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.

This efficacy is backed by robust clinical trials. The phase 3 multicenter, double-blind, randomized, placebo-controlled trial, involving 119 sites across nine countries, highlighted Mounjaro’s superior performance over placebo in substantial weight loss among participants. Over a 72-week treatment period, which included a comprehensive lifestyle intervention, participants on tirzepatide experienced significant weight reductions—15.0%, 19.5%, and 20.9% for the 5mg, 10mg, and 15mg doses, respectively, compared to a 3.1% reduction with placebo.

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 pens?

1. Timing: Administer Mounjaro once a week, ideally on the same day and time, to maintain steady medication levels.
2. 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.

1. Preparation: Use a new needle for each injection. Inspect your pen and needle for damage and ensure the medication is clear and colourless to slightly yellowish.
2. 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.

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

Mounjaro may not be suitable for all patients. The following patients with comorbidities should not use Mounjara or use with caution: 

Acute Pancreatitis

Patients with a history of pancreatitis must exercise caution with Mounjaro, as tirzepatide has not been extensively studied in this population. If symptoms of acute pancreatitis appear, the use of tirzepatide must be immediately halted. Tirzepatide is contraindicated if acute pancreatitis is diagnosed, underscoring the importance of patient education on recognizing these symptoms.

Hypoglycemia Risk

Tirzepatide, when used alongside insulin or sulphonylureas, increases the risk of hypoglycemia. It may necessitate a dosage adjustment of insulin or sulphonylurea drugs. Patients require careful monitoring to manage this risk effectively, highlighting the need for professional oversight in adjusting treatment plans.

Gastrointestinal Side Effects

The occurrence of nausea, vomiting, and diarrhea as side effects may lead to dehydration and potentially acute renal failure. Such risks are especially pertinent for elderly patients, who are more prone to complications. The emphasis is on preventive measures to maintain adequate hydration and electrolyte levels.

Severe Gastrointestinal Disease

Mounjaro is contraindicated for patients with severe gastrointestinal diseases, such as significant gastroparesis, due to the absence of relevant studies. This highlights the necessity for caution and thorough patient evaluation before considering tirzepatide as a treatment option.

Diabetic Retinopathy

Patients with specific forms of diabetic retinopathy should not use Mounjaro. 

Elderly Patients

The use of Mounjaro in patients over 85 years old is contraindicated.

Drug Interactions

Tirzepatide’s effect on the absorption rates of orally administered medications necessitates close monitoring, particularly for drugs with a narrow therapeutic index. This requirement underscores the importance of healthcare provider involvement in monitoring and adjusting medications as needed.

Special Populations

• Pregnancy: Mounjaro is contraindicated for use during pregnancy or for women planning to become pregnant.
• Breastfeeding: Given the unknowns regarding tirzepatide’s excretion in human milk, it cannot be used by breastfeeding women.

What Are the Most Common Side Effects of Mounjaro?

When starting Mounjaro for weight loss or diabetes management, many people experience very common side effects including diarrhea, nausea, vomiting, constipation, and low blood sugar, particularly when taken with certain diabetes medications. These symptoms are typically mild and tend to decrease over the first few weeks of treatment.

Can Mounjaro Cause Low Blood Sugar?

Yes, Mounjaro can lead to low blood sugar levels, especially when used in combination with other diabetes medications like insulin. Symptoms of low blood sugar include shaking, sweating, dizziness, hunger, and a rapid heartbeat. It’s crucial to inform your doctor if you experience these symptoms.

What Are Other Common Side Effects of Mounjaro?

Besides the very common side effects, Mounjaro users may also encounter a fast pulse, allergic reactions like eczema or itching, stomach pain, indigestion, bloating, gas, heartburn, fatigue, increased pancreatic enzymes, irritation at the injection site, low blood pressure, dizziness, and hair loss.

Are There Any Uncommon Side Effects of Mounjaro?

Uncommon side effects include gallstones, an increase in calcitonin levels, weight loss, pain at the injection site, and acute pancreatitis. If you experience severe stomach and back pain, indicating pancreatitis, seek immediate medical assistance.

Does Mounjaro Have Any Long-Term Side Effects?

Mounjaro is not known to cause long-term side effects. Most side effects are transient and improve within a few weeks or upon discontinuation of the medication.

What Should I Do If I Experience Serious Side Effects From Mounjaro?

Mounjaro can cause serious allergic reactions (anaphylaxis) and acute pancreatitis, which are medical emergencies. Symptoms like breathing difficulties, swelling of the throat, face, and mouth, fainting, severe stomach and back pain require immediate medical attention by calling emergency services or visiting an emergency department.

How Can I Manage Side Effects From Mounjaro?

To mitigate side effects, take Mounjaro consistently each week, manage nausea with cold water and smaller, non-greasy meals, consume adequate fiber, stay hydrated, and use anti-diarrhea medicine if necessary. Always follow your doctor’s prescribed dosage and report any persistent or bothersome side effects.

By formatting the information into questions commonly searched by users, the content is made more accessible and helpful to individuals seeking to understand the side effects associated with Mounjaro.

Weight Loss Treatment Comparison

Based on available studies, Mounjaro has been found to significantly outpace Wegovy in weight reduction efficacy. In clinical trials, Mounjaro’s peak dosing achieved weight loss in the range of 21% to 22.5%, a notable figure that aligns with outcomes usually seen with bariatric surgery. On the other hand, Wegovy has shown to facilitate an average weight loss of about 15% among adults. While direct comparisons between the two are scarce, evidence points to Mounjaro’s higher dosages surpassing Wegovy in facilitating weight loss.

Research shows that taking a single dose of tirzepatide can slightly reduce the effectiveness of your oral contraceptive. Specifically, the peak concentration (Cmax) and the overall exposure (AUC, which measures how much of the drug is in your bloodstream over time) of the hormones in your birth control pill are decreased.

If you miss a dose, take it as soon as you remember within 4 days. If it’s been more than 4 days, skip the missed dose and return to your regular schedule without doubling up. Speak to our clinician if you miss several doses as you may have to retitrate your dose. 

You can change the day of your weekly injection if needed, ensuring there’s at least a 3-day gap between doses.

How long you remain on Mounjaro weight loss injections varies based on your weight loss targets, clinical response, and long-term maintenance strategy. Research from the SURMOUNT-4 trial found that people who stayed on the Mounjaro weight loss injection were more likely to preserve their results and continue losing weight, while those who stopped treatment were more prone to weight regain. Your prescriber will monitor your progress and make dose adjustments to your Mounjaro pen where needed to ensure safe and effective use. When injecting Mounjaro, combining the treatment with sustainable lifestyle changes such as balanced nutrition and regular activity can help support lasting outcomes.

Mounjaro weight loss injections are designed to be used once per week. 

You can take your weekly dose at any time of day, with or without meals. The most important factor is consistency. Choose a specific day that fits easily into your routine and aim to inject Mounjaro at roughly the same time each week. Many patients find setting a phone reminder helpful to avoid missing a dose.

Changing Your Injection Day

If you need to adjust the day you take your Mounjaro weight loss injection, make sure there is a minimum gap of 72 hours (3 days) between doses. Once the new day is established, continue injecting Mounjaro weekly as normal.

Frequent changes to your dosing schedule are not recommended, as this may affect how well the medication works. Keeping a regular routine helps the Mounjaro pen deliver consistent results and supports steady progress.

When you stop taking Mounjaro weight loss injections your body may partially reverse the changes achieved while you were injecting Mounjaro. Evidence from the SURMOUNT-4 trial shows that stopping Mounjaro weight loss injections often leads to partial or significant weight regain. After 36 weeks of treatment using the Mounjaro pen, participants who lost at least 10% of their body weight were switched to a placebo. Over the following 52 weeks, 82% regained at least 25% of the weight they had lost, 24% regained 75% or more, and 9% regained all of the lost weight, despite receiving diet and exercise support. This suggests that the appetite-regulating and metabolic effects seen while injecting Mounjaro tend to diminish once treatment stops if you stop eating a balanced diet and dont take part in regular physical activity to help prevent weight gain when they come off the medicine.

Is weight regain inevitable after stopping the Mounjaro weight loss injection?

Not necessarily. Although the SURMOUNT-4 data shows a strong trend toward weight regain, this does not mean every patient will regain the same amount. Some participants maintained part of their weight loss through structured lifestyle changes, including calorie control and regular physical activity. In addition, researchers highlighted limitations such as incomplete tracking of diet and exercise habits and the fact the trial was industry funded, meaning further independent research is needed. This counter-argument supports the view that combining Mounjaro weight loss injections with long-term behaviour change may improve weight maintenance outcomes after stopping the medication.

Mounjaro weight loss injections are supplied in six different strength options. The dosing plan follows a gradual step-up approach, allowing your body time to adjust while supporting safe and effective weight loss.

The following Mounjaro weight loss injection strengths are currently available:

• 2.5mg

• 5mg

• 7.5mg

• 10mg

• 12.5mg

• 15mg

Mounjaro Dosing Options

Treatment with the Mounjaro pen begins at 2.5mg once weekly. This starting dose is used for the first four weeks and helps reduce the chance of early side effects while your body adapts to the medication.

After this initial phase, you may increase your dose to 5mg for a further four weeks. If additional weight loss support is needed and the treatment is well tolerated, your dose can be increased in steady 2.5mg stages at four-week intervals. The highest approved dose for injecting Mounjaro is 15mg per week.

You should never increase your dose earlier than advised. Raising your dose too quickly or exceeding the maximum strength may increase the risk of side effects such as nausea, stomach discomfort, dehydration, and fatigue. Always follow your prescriber’s instructions when adjusting your Mounjaro pen dosage.

Reaching the highest dose is not necessary for everyone. Many patients achieve strong results at moderate doses and choose to remain on a level that provides consistent weight loss with fewer side effects. While higher doses of Mounjaro weight loss injections may enhance appetite control, they may also increase the likelihood of side effects and overall treatment cost.