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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What is the clinically supported Dose of Mounjaro in the UK?
The term "clinically supported dose" for Mounjaro refers to the idea that one particular injection dose produces superior weight loss results. In reality, there is no single clinically supported dose — weight loss with tirzepatide (Mounjaro's active ingredient) varies significantly between individuals. The NHS and NICE recognise Mounjaro as a prescription-only weight management option for eligible UK adults, but the effective dose depends on personal tolerance, health status, and response. Understanding how Mounjaro dose titration works and what NHS guidance says can help you understand realistic expectations if you're considering this treatment through the NHS or private routes.
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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.
NHS Eligibility and Mounjaro Dosing in the UK
Mounjaro (tirzepatide) is approved in the UK for weight management and is available through NHS specialist tier 3 services as well as privately through online prescribing. The NHS KwikPen comes in six stepped doses: 2.5 mg, 5 mg, 7.5 mg, 10 mg, 12.5 mg, and 15 mg, with doses increased gradually over weeks to allow your body to adjust. Most patients begin on 2.5 mg and increase every four weeks if tolerated.
NHS eligibility criteria include:
- BMI of 30 kg/m² or above (or 27–29.9 with weight-related health conditions)
- Lower thresholds apply for South Asian, Chinese, Black African, and Black Caribbean adults
- Adults aged 18 or over
- Not pregnant, breastfeeding, or planning pregnancy
NICE has approved tirzepatide for use within NHS weight management services, but regional availability varies significantly. Clinical trial data showed average weight loss of approximately 15–21% of body weight across the dose range, though individual results vary substantially. There is no "clinically supported dose" that assures weight loss — effectiveness depends on adherence, lifestyle changes, and individual physiology.
Clinically BackedWeight Loss
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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 Mounjaro Access in the UK
NHS access to Mounjaro for weight management is through specialist tier 3 weight management services, typically requiring GP referral. Waiting lists can be lengthy in many regions, and availability depends on your local Integrated Care Board (ICB). Private access is faster — available through GPhC-registered online pharmacies following a remote clinical assessment by a UK-licensed prescriber, without NHS referral.
If you're eligible and want to explore Mounjaro, your GP can assess NHS options, or you can seek private prescribing. Use our free BMI calculator to check your starting point, and our GLP-1 weight loss calculator to estimate potential outcomes at different tirzepatide doses. Remember: medication works best alongside reduced-calorie diet and increased physical activity. No dose is "clinically supported" without lifestyle support.
- 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.
Is there a "clinically supported dose" of Mounjaro that works best for everyone?
No. The term "clinically supported dose" is informal marketing language without clinical basis. Mounjaro's effectiveness varies between individuals. Doses range from 2.5 mg to 15 mg weekly, titrated over weeks. Clinical trials showed average weight loss of 15–21% body weight, but individual results depend on tolerance, adherence, diet, activity, and personal metabolism. Your prescriber will adjust your dose based on your response and side effects.
What dose of Mounjaro do most people reach on the NHS?
NHS guidance typically escalates doses gradually over 16–20 weeks. Many people find good results at 10 mg or 12.5 mg weekly. The maximum licensed dose is 15 mg, but not everyone needs or tolerates this dose. Your prescriber will assess your progress and adjust accordingly. There's no standard "best dose" — it's personalised.
How does Mounjaro dosing work, and how often do doses increase?
Mounjaro uses a KwikPen delivering a once-weekly injection. Starting dose is 2.5 mg; if tolerated, the dose increases every 4 weeks (2.5 mg → 5 mg → 7.5 mg → 10 mg → 12.5 mg → 15 mg). You stay on each dose for at least four weeks before escalating. If side effects occur, your prescriber may pause escalation or reduce dose.
Is Mounjaro available on the NHS for weight management in the UK?
Yes. NICE has approved tirzepatide (Mounjaro) for weight management within NHS specialist tier 3 services. Access requires GP referral and assessment by a specialist weight management team. Availability and waiting times vary significantly by region. Private access is also available through online prescribing without NHS referral, following a clinical assessment.
What's the difference between Mounjaro and Wegovy for weight loss on the NHS?
Mounjaro (tirzepatide) is a dual GIP and GLP-1 receptor agonist; Wegovy (semaglutide) is a GLP-1 agonist only. Both are once-weekly injections licensed for UK weight management. Clinical trials showed similar average weight loss (~15–21% and ~15% respectively), but individual response varies. Eligibility, cost, and availability differ — your GP or prescriber will discuss which is suitable for you.
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.