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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Do You Put Weight Back On After Stopping Mounjaro?
When you stop taking Mounjaro, many people naturally regain some weight — this is an important consideration before starting treatment. Weight regain after stopping any weight loss medication is common because the underlying appetite regulation returns to baseline. However, the amount regained varies significantly between individuals and depends on lifestyle changes maintained during treatment. Understanding what to expect after stopping, and how to prevent excessive regain, helps you make an informed decision about whether this weekly weight loss injection is right for your circumstances and long-term health goals.
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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.
Weight Regain After Stopping Mounjaro: What the Evidence Shows
Clinical data from the SURMOUNT trials showed that after stopping Mounjaro (tirzepatide), participants typically regained approximately 50% of the weight they had lost within one year of stopping. However, this is not universal — some individuals maintained most of their weight loss, whilst others regained more. The key factor determining long-term weight maintenance is whether lifestyle changes made during treatment are sustained after stopping.
During Mounjaro treatment, the weekly KwikPen injection suppresses appetite and helps regulate blood sugar, making it easier to eat less and move more. Once you stop, this pharmacological support is removed. Your appetite hormones return to their pre-treatment baseline, and without the medication's support, maintaining a reduced-calorie diet becomes significantly harder. This is why experts emphasise that Mounjaro works best when combined with sustainable dietary and physical activity changes that can be maintained indefinitely.
Important to note: weight regain is not a failure or sign that Mounjaro didn't work. Rather, it reflects the reality that obesity is a chronic condition requiring long-term management — whether through medication, lifestyle change, or typically, a combination of both.
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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.
Accessing Mounjaro in the UK: NHS vs Private Routes and Costs
In the UK, Mounjaro is available through both NHS specialist weight management services and private prescription routes, each with different costs and accessibility. NHS access is typically free at point of use but requires referral to a tier 3 specialist weight management service — availability varies significantly by region, and waiting lists can be lengthy (sometimes months or years). Your GP must first assess eligibility and refer you to your local integrated care board (ICB) weight management pathway.
Private access is available without NHS referral through GPhC-registered online prescribing services. You'll complete an online consultation with a UK-licensed prescriber, who assesses suitability, and if approved, the prescription is dispensed by a registered pharmacy. Private Mounjaro typically costs £120–£300 per month depending on your dose — starting doses cost less than maximum doses. This cost is in addition to any consultation fee (usually £20–£50). Before starting any treatment, weigh the financial commitment against potential benefits and discuss long-term affordability with your prescriber.
- 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 percentage of weight do people regain after stopping Mounjaro?
Clinical trials showed approximately 50% of lost weight is typically regained within one year of stopping, though individual results vary significantly. Some people maintain most weight loss through sustained lifestyle changes, whilst others regain more. The key predictor is whether the reduced-calorie diet and increased physical activity adopted during treatment are maintained afterwards.
Can I restart Mounjaro if I regain weight after stopping?
Yes, you can restart Mounjaro if eligible and if your prescriber agrees it's appropriate. However, restarting involves repeating the dose titration schedule (starting at 2.5mg and gradually increasing weekly), which takes several weeks. Discuss long-term management plans with your GP or prescriber before stopping — sometimes continuing at a lower maintenance dose may be more effective than stopping and restarting.
How much does Mounjaro cost privately in the UK?
Private Mounjaro costs approximately £120–£300 per month depending on your dose, plus any consultation fees (usually £20–£50). Starting doses (2.5mg) are cheaper than maximum doses (15mg). Costs vary between different online prescribing services, so compare options. Always check whether the quoted price includes the consultation fee and how often you need follow-up assessments.
How do I access Mounjaro through the NHS in the UK?
Ask your GP for a referral to your local tier 3 specialist weight management service. You must have a BMI of 30 or above (or 27+ with weight-related health conditions) and meet other eligibility criteria. NHS availability varies by region — some areas have short waiting lists, others have waiting times of 12+ months. Private prescription is an alternative if NHS waiting times are too long.
What's the difference between Mounjaro and Wegovy for weight management?
Mounjaro (tirzepatide) is a dual GIP and GLP-1 receptor agonist, whilst Wegovy (semaglutide) is a GLP-1-only medication. In clinical trials, Mounjaro showed slightly higher average weight loss (approximately 21% vs 15%), but both are effective. Both are prescription-only, available through NHS or private routes in the UK, and both require lifestyle changes to maintain results long-term.
Ready to take control of your weight loss journey?
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