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 Dosage Amounts and UK Costs Explained
Mounjaro (tirzepatide) is available in six different dosage strengths in the UK, starting from 2.5 mg and scaling up to the maximum 15 mg once-weekly injection. The cost and availability of Mounjaro in the UK depends on whether you access it through the NHS or via private prescription following an online clinical assessment. Understanding the dosage schedule, dose titration process, and cost implications will help you make an informed decision about this weight management option. Use our free GLP-1 weight loss calculator to explore potential outcomes at different doses.
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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 Dosage Amounts and UK Private Access Costs
Mounjaro is available in six prescription doses: 2.5 mg, 5 mg, 7.5 mg, 10 mg, 12.5 mg, and 15 mg, each delivered as a once-weekly injection via a KwikPen device. The standard dose titration schedule involves starting at 2.5 mg for weeks 1–4, then escalating by 2.5 mg every four weeks, unless your prescriber adjusts your schedule. The maximum maintenance dose is 15 mg once weekly.
Private prescription costs in the UK typically range from £129 to £320 per month, depending on your dose and the prescribing service provider. Prices are generally lower for starting doses (2.5–5 mg) and higher for maximum doses (15 mg). Each KwikPen contains four pre-filled doses (a four-week supply). Unlike the NHS, private access does not require a referral to specialist weight management services—you can access a UK-licensed prescriber online following a brief clinical assessment. Availability and pricing vary between GPhC-registered pharmacies.
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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 and What to Expect
NHS access: NICE has approved tirzepatide (Mounjaro) for use within NHS specialist weight management services at tier 3 or 4. However, NHS availability is limited and varies significantly by region and ICB. Waiting lists can extend from several months to years in many areas. You'll need a GP referral to a specialist weight management service, where eligibility will be assessed based on your BMI and health conditions.
Private access: You can obtain a Mounjaro prescription through an online consultation with a UK-licensed prescriber, without NHS referral. The process typically involves completing a health questionnaire, undergoing a clinical assessment, and receiving a prescription if appropriate. Prescriptions are dispensed by GPhC-registered pharmacies. This route offers faster access but requires private payment. Our BMI calculator can help confirm whether you may meet eligibility criteria (BMI 30+, or 27+ with weight-related health conditions).
- 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 standard starting dose of Mounjaro is 2.5 mg once weekly for the first four weeks. This is the lowest dose in the KwikPen range and is used to allow your body to adjust to the medication. After four weeks, your prescriber will typically increase your dose by 2.5 mg increments every four weeks, unless they recommend a slower escalation schedule based on your tolerance.
How much does Mounjaro cost on private prescription in the UK?
Private prescription costs for Mounjaro in the UK typically range from £129 to £320 per month, depending on your dose and the prescribing service. Starting doses (2.5–5 mg) are generally cheaper, while maintenance doses (10–15 mg) are more expensive. Each KwikPen contains four weeks of injections. Prices vary between GPhC-registered providers, so it's worth comparing options.
Can I access Mounjaro through the NHS in the UK?
Yes, NICE has approved tirzepatide (Mounjaro) for NHS use through specialist tier 3/4 weight management services. However, NHS access is limited and varies by region. You'll need a GP referral and specialist assessment. Waiting lists are long in many areas. Private prescription access offers faster availability but requires out-of-pocket payment.
What is tirzepatide and how is it different from semaglutide?
Tirzepatide (Mounjaro) is a dual GIP and GLP-1 receptor agonist—it activates two natural hormone pathways. Semaglutide (Wegovy) is a GLP-1 receptor agonist only, activating one pathway. In clinical trials, the dual mechanism of tirzepatide resulted in slightly greater average weight loss (around 15–21% of body weight) compared to semaglutide (around 15%), though individual results vary significantly.
How long does it take to reach the maximum Mounjaro dose?
The standard dose titration schedule takes approximately 20 weeks to reach the maximum 15 mg dose. You start at 2.5 mg for weeks 1–4, then increase by 2.5 mg every four weeks. However, your prescriber may recommend a slower or faster schedule based on how well you tolerate each dose and any side effects you experience.
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.