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
Ordering 5mg Mounjaro vs Wegovy — What's the Difference?
If you're considering ordering 5mg Mounjaro or looking at Wegovy as an alternative, understanding how they differ is essential. Both are prescription-only weight management injections licensed in the UK, but they work through different mechanisms and have distinct dosing schedules. This guide compares the two based on clinical trial data, how they're prescribed, and what might make one more suitable for you personally. Our GLP-1 weight loss calculator can help you explore potential outcomes with either medication.
10,000+ calculations today · NHS-aligned thresholds · 100% free
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.
How Mounjaro and Wegovy Work — The Key Difference
Mounjaro (tirzepatide) is a dual GIP and GLP-1 receptor agonist, meaning it activates two natural hormone pathways in your body. This dual action may help regulate appetite more effectively than a single-pathway medication. In the SURMOUNT-1 clinical trial, the 5mg dose produced an average weight loss of approximately 15% body weight over 72 weeks alongside diet and exercise.
Wegovy (semaglutide) is a GLP-1 receptor agonist only — it activates one hormone pathway. In the STEP-1 clinical trial, semaglutide produced an average weight loss of approximately 14.9% body weight at 68 weeks. Both medications slow gastric emptying and reduce appetite, but Mounjaro's dual mechanism may provide additional metabolic support.
Important: Individual results vary significantly. Clinical trial averages do not predict personal outcomes. A prescriber will assess which mechanism suits your health profile better.
Clinically BackedWeight Loss
No appointments. No waiting rooms. Just care — from a UK-regulated online pharmacy.
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.
Dosing Schedules — 5mg Mounjaro vs Wegovy Maximum Dose
The 5mg Mounjaro dose is typically reached after 8 weeks of titration (starting at 2.5mg for weeks 1–4, then moving to 5mg for weeks 5–8). This is an intermediate maintenance dose; many patients continue escalating to higher doses (7.5mg, 10mg, 12.5mg, up to 15mg maximum). Wegovy reaches its maximum 2.4mg dose after 16 weeks of slower titration (0.25mg → 0.5mg → 1mg → 1.7mg → 2.4mg). The faster Mounjaro escalation means reaching higher doses sooner, though 5mg may be sufficient for some users. Both require once-weekly injections. Your prescriber will determine the right escalation pace and target dose for your individual circumstances.
- 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 or Wegovy more effective for weight loss?
Clinical trials showed slightly higher average weight loss with Mounjaro (15% vs 14.9% with Wegovy), but individual results vary widely. Effectiveness depends on your metabolism, lifestyle adherence, and how your body responds to each medication's mechanism. Your prescriber will assess which is more appropriate based on your health profile and other medications.
Can I switch from Mounjaro 5mg to Wegovy later?
Yes, switching is possible and may be managed by your prescriber if one medication isn't working well for you or side effects are problematic. There is no official conversion chart — your prescriber will assess your individual response and recommend the appropriate Wegovy dose if switching is suitable.
Which one costs more when ordering in the UK?
Costs vary by provider and dose. Private pricing typically ranges from £129–£320 per month for either medication. NHS access is through specialist tier 3 services where cost is not a barrier, though waiting lists vary by region. Always ask your prescriber or provider for current pricing.
Do Mounjaro and Wegovy have different side effects?
Both cause similar common side effects (nausea, diarrhoea, constipation, stomach pain). Individual tolerance varies. Some people tolerate one better than the other. Starting at a lower dose and titrating slowly — as both medications do — helps minimise side effects in most users. Your GP can advise which is more suitable based on your medical history.
How do I order 5mg Mounjaro — NHS or private?
NHS access requires referral to a specialist tier 3 weight management service via your GP; availability varies by region and waiting lists can be long. Private ordering is available through a UK-licensed prescriber following an online clinical assessment with a GPhC-registered pharmacy. Both routes require a prescription; you cannot order without clinical assessment.
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.