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 Weight Loss Graph — NHS and Clinical Data
Understanding how Mounjaro produces weight loss is key to setting realistic expectations. Clinical trial data shows that tirzepatide—the active ingredient in Mounjaro—produces a progressive weight loss graph over time, with greater loss at higher doses. This guide explains what NHS specialist services and clinical evidence tell us about weight loss progression, eligibility criteria for UK adults, and how Mounjaro compares to other weekly weight loss injections like Wegovy. Individual results vary significantly, and weight loss medication works best alongside reduced-calorie diet and increased physical activity.
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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 Clinical Trial Weight Loss Data
In the UK, Mounjaro (tirzepatide) is a prescription-only weekly weight loss injection available through NHS specialist tier 3 weight management services and private prescribing. The SURMOUNT-1 clinical trial—the largest trial of Mounjaro for weight management—provides the most reliable weight loss graph data available.
- At 5 mg dose: Average weight loss was approximately 15% of body weight over 72 weeks
- At 10 mg dose: Average weight loss increased to approximately 19.5% of body weight
- At 15 mg (maximum dose): Average weight loss reached approximately 20.9% of body weight
These figures represent the NHS-recognised evidence base. Weight loss was achieved with dose titration (gradual increase every 4 weeks) alongside a reduced-calorie diet and lifestyle changes. Individual results vary considerably—some participants lost more, others less. The weight loss graph shows most rapid loss during months 2–6, with continued steady loss through month 12.
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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 Dose Titration Timeline
NHS route: Mounjaro is approved by NICE for use within NHS tier 3 specialist weight management services. Your GP refers you to a specialist clinic, which manages your treatment and titration. Availability and waiting times vary significantly by region. Private route: Available through registered online prescribers following a clinical assessment; faster access but user pays (typically £129–£280 monthly depending on dose).
The standard NHS titration schedule increases every 4 weeks: 2.5 mg (weeks 1–4) → 5 mg (weeks 5–8) → 7.5 mg (weeks 9–12) → 10 mg onwards. Try our GLP-1 weight loss calculator to estimate potential outcomes at different doses, and use our BMI calculator to understand your starting point against NHS healthy weight thresholds.
- 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.
How quickly does Mounjaro show weight loss on a graph?
Clinical trials show most weight loss occurs in the first 3–4 months of treatment. The steepest part of the weight loss graph typically appears during months 2–6, with gradual continued loss through month 12 and beyond. Weight loss rate depends on the dose—5 mg produces slower loss than 15 mg. Individual variation is significant; your personal graph may look different.
Is Mounjaro weight loss assured in the NHS?
No. While clinical trials showed average weight loss of 15–21%, individual results vary. Some people lose more, some less. Weight loss depends on dose adherence, diet, physical activity, genetics, and metabolic factors. Your NHS specialist will monitor your progress and adjust treatment accordingly.
How does Mounjaro's weight loss graph compare to Wegovy?
Mounjaro (tirzepatide) is a dual GIP and GLP-1 agonist; Wegovy (semaglutide) is a GLP-1-only injection. Clinical trials show Mounjaro produces slightly greater average weight loss (20.9% at maximum dose) than Wegovy (approximately 15%). However, individual responses vary, and direct comparison should be discussed with your prescriber.
Can I access Mounjaro on the NHS for weight loss?
Yes, if you meet criteria: BMI ≥30, or BMI 27–29.9 with weight-related health conditions (diabetes, hypertension, sleep apnoea, cardiovascular disease). Access is through NHS tier 3 specialist services via GP referral. Availability and waiting times vary by region. Private access is available without referral.
What does the weight loss graph show about long-term results?
Clinical trial graphs show sustained weight loss through 72 weeks (over 18 months). After reaching maximum dose, weight tends to stabilise rather than plateau sharply. If treatment stops, some weight regain typically occurs, which is why medication is viewed as ongoing, not a one-off course.
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.