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
Free tracker included with every download this week
What Does 5mg Mounjaro Do vs Wegovy?
5mg is the first standard maintenance dose of Mounjaro (tirzepatide), typically reached after the starting 2.5mg dose has been increased over 4 weeks. At 5mg, you're getting the dual GIP and GLP-1 receptor agonist benefits that set Mounjaro apart from Wegovy, which uses only a GLP-1 mechanism. Understanding what 5mg means in clinical context — and how it compares to Wegovy doses — helps you understand what a prescriber might recommend. Both are prescription-only medications requiring clinical assessment.
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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.
How 5mg Mounjaro Compares to Wegovy Doses
In the SURMOUNT-1 clinical trial, participants on 5mg Mounjaro achieved an average weight loss of approximately 15% of body weight over 72 weeks, alongside a reduced-calorie diet and increased physical activity. The approximate Wegovy equivalent to 5mg Mounjaro is 0.5mg — though these are not direct clinical equivalences.
The key difference: Mounjaro activates both GIP and GLP-1 pathways, while Wegovy (semaglutide) activates GLP-1 only. In STEP-1 trials, Wegovy at 2.4mg (its maximum dose) achieved approximately 14.9% average weight loss. This suggests Mounjaro's dual mechanism may offer slightly stronger results, though individual results vary significantly based on diet, activity, metabolism, and adherence.
5mg is often where dose titration pauses to assess tolerance before escalating further. Each dose increase follows a 4-week period on the previous dose.
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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.
Choosing Between 5mg Mounjaro and Wegovy
Your prescriber will assess which medication suits your individual health profile — both require a clinical assessment before prescription. Factors considered include your BMI, any weight-related health conditions, side effect tolerance, previous medication responses, and whether you're already on other medications.
Both Mounjaro and Wegovy are available through NHS specialist weight management services (with regional variation and waiting lists) or private online prescription services in the UK. A UK-licensed prescriber will determine the starting dose and escalation plan for you specifically. Neither medication is a standalone solution — both work alongside dietary changes and increased physical activity.
Use our GLP-1 weight loss calculator to explore potential weight loss projections at different doses, and our BMI calculator to understand your current health context.
- 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 5mg Mounjaro a high dose?
No. 5mg is the first standard maintenance dose, typically reached in week 5. Mounjaro ranges from 2.5mg (starting) to 15mg (maximum). Most people stay on 5–10mg doses. Your prescriber may escalate gradually based on tolerance and weight loss response, typically increasing every 4 weeks.
How much weight does 5mg Mounjaro typically cause?
In SURMOUNT-1 trials, 5mg Mounjaro resulted in approximately 15% average body weight loss over 72 weeks alongside lifestyle changes. However, individual results vary — some people lose more, some less. Results depend on adherence, diet, exercise, metabolism, and other factors. A prescriber cannot assures specific outcomes.
Can I switch from 5mg Mounjaro to Wegovy?
Only a prescriber can manage any switch between medications. Approximate equivalences exist — 5mg Mounjaro is roughly equivalent to 0.5–1mg Wegovy — but there is no official conversion chart. Any change requires clinical assessment and dose adjustments. Never switch on your own.
Why does a prescriber choose Mounjaro over Wegovy?
Prescribers consider multiple factors: your BMI, weight-related health conditions, previous medication responses, side effects you've experienced, and whether you're taking other medications (especially oral contraceptives or diabetes medications). Mounjaro's dual GIP+GLP-1 mechanism may benefit some patients more; Wegovy's longer clinical history may suit others. It's an individualised decision.
Is Mounjaro available on the NHS for 5mg dose?
Yes, Mounjaro is NICE-approved for NHS specialist weight management services in the UK. However, access is through tier 3 specialist services (referral from your GP), not standard GP prescription. Availability and waiting times vary significantly by region (ICB). Private prescription is available through UK-licensed online prescribers without NHS referral.
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.