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's the Wegovy 1mg Equivalent to Mounjaro?
Wegovy (semaglutide) 1mg and Mounjaro (tirzepatide) are not directly equivalent because they work through different mechanisms, but there are approximate dose comparisons. Wegovy 1mg is roughly equivalent to Mounjaro 5–7.5mg in terms of appetite suppression effects, though individual responses vary significantly. Both are prescription-only GLP-1 and GIP/GLP-1 receptor agonists available in the UK through NHS specialist services or private online prescribing. Understanding the differences helps you and your GP choose the right option for your health needs.
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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.
Approximate Dose Equivalence & How They Differ
Wegovy and Mounjaro work differently despite both being weight loss injections. Wegovy is a GLP-1 receptor agonist only, while Mounjaro is a dual GIP and GLP-1 agonist — this dual action means Mounjaro may have a stronger effect at lower doses. Approximate equivalence:
- Wegovy 0.5mg ≈ Mounjaro 2.5–5mg
- Wegovy 1mg ≈ Mounjaro 5–7.5mg
- Wegovy 1.7mg ≈ Mounjaro 10mg
- Wegovy 2.4mg (max) ≈ Mounjaro 15mg (max)
These are clinical practice approximations only — not official conversion guidelines. Clinical trials showed Mounjaro achieved slightly higher average weight loss (20.9% vs 14.9% body weight) at maximum doses. Any switch between medications must be managed by your prescriber, who will assess your individual response and health context. Use our free GLP-1 weight loss calculator to explore potential outcomes at different doses.
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.
UK Private Cost & Access Routes
Private prescription costs vary by provider and dose. Wegovy typically costs £150–£250 per month depending on dose strength, while Mounjaro ranges £160–£280. Both require an online clinical assessment with a UK-licensed prescriber before prescription. Private access is faster than NHS (usually within days rather than months) and does not require GP referral. NHS access through specialist tier 3 weight management services is free but involves longer waiting lists in many regions. Calculate your BMI using our free calculator to check your eligibility — generally adults with BMI 30+ or 27+ with weight-related conditions qualify for either medication. Your prescriber will assess which option suits your health profile, medical history, and previous response to similar treatments.
- 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 Wegovy 1mg the same strength as any Mounjaro dose?
No, they're not directly comparable because they use different mechanisms. Wegovy 1mg is approximately equivalent to Mounjaro 5–7.5mg in appetite-suppressing effects, but Mounjaro's dual action may make it somewhat more potent. Your prescriber will determine the best dose for you individually.
Which is cheaper in the UK — Wegovy or Mounjaro?
Costs are similar, ranging £150–£280 monthly depending on dose and private provider. NHS provision is free but involves longer waits. Private prices vary, so compare providers. Neither is available on standard NHS prescription without specialist service referral.
Can I switch from Wegovy to Mounjaro in the UK?
Yes, but only under prescriber guidance. There's no official conversion chart — your prescriber will typically restart on a lower Mounjaro dose and titrate upwards. Switching usually requires a new clinical assessment and prescription.
Do I need NHS referral to get Wegovy or Mounjaro privately?
No. Private prescription requires only an online clinical assessment with a UK-licensed prescriber — no GP referral needed. However, your prescriber will ask about your GP and medical history as part of the assessment.
What's the difference between Mounjaro's KwikPen and Wegovy's pen?
Both are pre-filled auto-injection pens for once-weekly dosing. Mounjaro's KwikPen delivers tirzepatide; Wegovy's pen delivers semaglutide. Storage, injection sites, and disposal are similar. Your pharmacy will provide instructions specific to your medication.
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.