The UK's most complete GLP-1 guide
Every Question Answered. Every Side Effect Explained.
- How GLP-1 medications work
- Mounjaro vs Wegovy compared
- Injection instructions
- Side effects & solutions
- What to eat on treatment
- FAQs answered
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Mounjaro Injection Dose — UK Cost & Access Guide
Mounjaro (tirzepatide) is a prescription-only weight loss injection available in the UK through both NHS specialist services and private online prescribing routes. The dose you receive depends on your individual health assessment and how your body responds to treatment. Understanding the dosing schedule, costs, and how to access Mounjaro can help you make an informed decision about whether this weekly weight loss injection is right for you.
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Calculate Your BMI Instantly
Enter your height and weight below. Supports both imperial (stone & lbs) and metric (kg). Results include NHS category, healthy weight range, and ethnicity adjustments.
What Is BMI and Why Does It Matter?
Body Mass Index (BMI) is the most widely used screening tool for assessing whether your weight falls within a healthy range. Used by the NHS, GPs, and weight management services across the UK, BMI provides a quick snapshot of your weight relative to your height. The formula is simple: your weight in kilograms divided by your height in metres squared (kg/m²).
While BMI isn't a perfect measure — it doesn't account for muscle mass, bone density, or fat distribution — it remains the standard first step in identifying potential weight-related health risks including type 2 diabetes, cardiovascular disease, high blood pressure, and certain cancers.
The NHS also recommends adjusted thresholds for people of South Asian, Chinese, or Black African heritage — a BMI of 23 or above is classified as overweight, and 27.5 as obese. Our calculator includes this adjustment as a one-click toggle.
Mounjaro Doses and UK Private Prescription Costs
Mounjaro is available in five dose strengths administered as a once-weekly injection using a pre-filled KwikPen device. The starting dose is 2.5 mg, with escalation to 5 mg, 7.5 mg, 10 mg, 12.5 mg, and finally 15 mg as the maximum maintenance dose. Most patients spend a minimum of four weeks on each dose before increasing, allowing your body to adjust.
In clinical trials, average weight loss with a weekly weight loss injection like Mounjaro ranged from approximately 15% to 21% of body weight over 72 weeks, though individual results vary significantly. Private UK prescriptions for Mounjaro typically cost between £129 and £320 per month depending on which dose you're prescribed and the provider. Each KwikPen contains four weekly injections (one month's supply). Costs vary because different online pharmacies set their own pricing, and higher doses naturally cost more than lower maintenance doses.
- 2.5 mg starter dose: Generally the lowest cost (approximately £129–£160/month)
- 5–10 mg maintenance doses: Mid-range pricing (approximately £180–£240/month)
- 15 mg maximum dose: Highest cost (approximately £280–£320/month)
Clinically BackedWeight Loss
No appointments. No waiting rooms. Just care — from a UK-regulated online pharmacy.
How It Works
Three simple steps to understand your weight and take action.
Enter your height and weight in our free calculator. Get your BMI, NHS category, healthy weight range, and ethnicity-adjusted thresholds instantly.
If your BMI suggests you're overweight or obese, explore our GLP-1 calculators to project potential weight loss on Mounjaro or Wegovy.
Use our progress tracker to log your weight weekly, visualise your journey with charts, and stay motivated — all stored privately in your browser.
Free Weight Loss Tools & Guides
Everything you need to understand your weight, explore medication options, and track your progress — completely free.
NHS vs Private Access — How to Get Mounjaro in the UK
The two main routes to access Mounjaro in the UK are NHS specialist weight management services and private online prescription services. NHS access is available through NICE-approved tier 3 or tier 4 weight management services, but you typically need a GP referral, and availability varies significantly by region. Waiting lists for NHS specialist services can extend months or even years in many areas.
Private access is faster: you complete an online consultation with a UK-licensed prescriber, receive a prescription if clinically appropriate, and the medication is dispensed by a GPhC-registered pharmacy. The entire process usually takes 2–5 days. To qualify for either route, you generally need a BMI of 30 or above, or BMI of 27–29.9 with a weight-related health condition (such as type 2 diabetes or high blood pressure). Use our free BMI calculator above to check your BMI instantly, and our GLP-1 weight loss calculator to estimate potential results at different doses.
- Dual GIP/GLP-1 receptor agonist
- Up to 22.5% body weight loss (SURMOUNT-1)
- Weekly injection, dose escalation over 20+ weeks
- Available via private prescription in the UK
- Doses: 2.5mg → 5mg → 7.5mg → 10mg → 12.5mg → 15mg
- GLP-1 receptor agonist
- Up to 15–17% body weight loss (STEP trials)
- Weekly injection, 5-step dose escalation
- NHS & private prescription available
- Doses: 0.25mg → 0.5mg → 1mg → 1.7mg → 2.4mg
Mounjaro vs Wegovy: Head-to-Head
A side-by-side comparison of the two most popular GLP-1 weight loss medications available in the UK.
| Feature | Mounjaro | Wegovy |
|---|---|---|
| Drug class | Dual GIP/GLP-1 agonist | GLP-1 agonist |
| Active ingredient | Tirzepatide | Semaglutide |
| Avg. weight loss | 15–22.5% | 12–17% |
| Key trial | SURMOUNT-1 (2022) | STEP 1 (2021) |
| Max dose | 15 mg weekly | 2.4 mg weekly |
| Escalation period | 20–32 weeks | 16–20 weeks |
| Administration | Weekly injection (pen) | Weekly injection (pen) |
| NHS availability | Private prescription only | NHS & private |
| Approx. private cost | £150–£250/month | £150–£300/month |
| Common side effects | Nausea, diarrhoea, constipation | Nausea, vomiting, diarrhoea |
Data sourced from SURMOUNT-1 and STEP 1 clinical trials. Costs are approximate and vary by provider. Always consult a prescriber.
Am I Eligible for Weight Loss Medication?
In the UK, eligibility for GLP-1 weight loss medications like Mounjaro and Wegovy is based on your BMI and overall health profile.
- BMI of 30 or above (obese)
- Age 18 or over
- No contraindicated conditions
- Committed to lifestyle changes
- BMI of 27 or above
- Plus type 2 diabetes
- Or high blood pressure
- Or obstructive sleep apnoea
Use our BMI calculator to check whether your BMI falls within the eligible range.
How We Built These Tools
Every calculator and guide on myweightcheck is built with accuracy and transparency in mind. Our BMI calculator uses the standard WHO formula with NHS-aligned category thresholds. Our GLP-1 projections are modelled on published clinical trial data from SURMOUNT and STEP studies.
All data stays on your device. We don't require sign-ups, and we don't store your health information on any server. Your progress tracker saves data locally in your browser using localStorage, so only you can see it.
We're based in the UK and our tools are designed specifically for UK users — supporting stone & lbs by default, referencing NHS guidelines, using NICE-approved medication data, and linking to GPhC-registered pharmacies.
Frequently Asked Questions
Common questions about BMI, weight loss medications, and our free UK tools.
What is the starting dose of Mounjaro?
The starting dose is 2.5 mg once weekly. This is an adjustment dose used for the first four weeks to allow your body to tolerate the medication. After four weeks, most people escalate to the 5 mg maintenance dose, with further increases possible up to a maximum of 15 mg per week, depending on clinical response and tolerability.
How much does Mounjaro cost in the UK on private prescription?
Private prescription costs for Mounjaro typically range from £129 to £320 per month depending on the dose prescribed. Starting doses (2.5–5 mg) cost less than higher maintenance doses. Pricing varies between online pharmacies, so comparing providers can help you find the best cost. Each KwikPen contains four weekly injections (one month's supply).
Can I get Mounjaro on the NHS in the UK?
Yes, Mounjaro is NICE-approved for use within NHS specialist weight management services. However, access requires a GP referral to a tier 3 or tier 4 service, and availability varies significantly by region. NHS waiting lists can be lengthy. Private online prescription is often faster (2–5 days) if you meet clinical eligibility criteria.
How long does Mounjaro dose titration take?
Mounjaro dose titration typically takes 20–24 weeks to reach the maximum 15 mg dose. You spend a minimum of four weeks on each dose level (2.5 mg, 5 mg, 7.5 mg, 10 mg, 12.5 mg, 15 mg) before escalating. Many patients find their effective dose earlier and remain on a lower maintenance dose if weight loss is adequate.
What's the difference between Mounjaro and Wegovy?
Mounjaro (tirzepatide) is a dual GIP and GLP-1 receptor agonist with a maximum dose of 15 mg weekly, whilst Wegovy (semaglutide) is a GLP-1-only medication with a maximum dose of 2.4 mg weekly. In clinical trials, Mounjaro showed slightly higher average weight loss (15–21% vs approximately 15% with Wegovy), though individual results vary. Both are prescription-only and available through NHS or private routes in the UK.
Ready to take control of your weight loss journey?
Start with a free BMI check, explore your GLP-1 options, or begin tracking your progress today. No sign-up. No cost. Just results.