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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What Is 1mg Wegovy In Mounjaro — Dose Equivalence Guide
If you're comparing Wegovy and Mounjaro, you may wonder how doses convert between the two medications. While 1mg Wegovy doesn't have an exact Mounjaro equivalent, approximate conversions suggest 1mg Wegovy is roughly equivalent to 5–7.5mg Mounjaro. However, these are not interchangeable — any switch between medications must be managed by your prescriber. Both are prescription-only GLP-1 or GIP/GLP-1 receptor agonists used for weight management in UK adults, but they work slightly differently and have different access routes through NHS services or private prescription.
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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.
Approximate Dose Equivalence and Cost Context in the UK
Approximate Mounjaro equivalent to 1mg Wegovy:
- 1mg Wegovy ≈ 5–7.5mg Mounjaro (approximate only)
- These conversions are based on clinical practice, not official manufacturer guidance
- Individual response varies significantly — equivalent doses do not assures equivalent results
In the UK private market, costs differ between the two medications. Wegovy at 1mg typically costs £129–£180 per month, while Mounjaro at equivalent doses (5–7.5mg) ranges from £149–£220 per month depending on the provider. These prices fluctuate and vary by clinic. Any change between medications must be prescribed and monitored by a UK-licensed prescriber. Neither medication should be switched without medical guidance, as titration schedules, side effect profiles, and individual tolerance differ. Our GLP-1 weight loss calculator can help you understand projected weight loss at different doses of either medication.
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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 — How to Get Wegovy or Mounjaro in the UK
NHS access: Both Wegovy and Mounjaro are available through specialist tier 3 weight management services following GP referral. NICE has approved tirzepatide (Mounjaro) and semaglutide (Wegovy) for NHS use, but availability depends on your local Integrated Care Board (ICB). Waiting times can be significant, often several months to years in many areas. Your GP can discuss NHS eligibility and refer you if appropriate.
Private access: Both medications are available through private online prescribing services following a confidential consultation with a UK-licensed prescriber. The process typically takes 24–48 hours from consultation to prescription. You'll need to complete a health questionnaire, and the prescriber will assess whether the medication is suitable for you based on your BMI, medical history, and any existing health conditions. Once prescribed, the medication is dispensed by a GPhC-registered pharmacy.
- 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 1mg Wegovy the same strength as 5mg Mounjaro?
No. While approximately equivalent in effect, they are not identical. 1mg Wegovy and 5mg Mounjaro have different chemical compositions and mechanisms. Wegovy is a GLP-1 agonist only, while Mounjaro is a dual GIP/GLP-1 agonist. Any dose conversion should only be made under prescriber guidance.
Can I switch from Wegovy 1mg to Mounjaro directly?
You should not switch medications without prescriber involvement. If considering a switch, your GP or prescriber will create a transition plan. This typically involves completing your current Wegovy regimen before starting Mounjaro at an appropriate starting dose, which is usually 2.5mg.
Why does Mounjaro cost more than Wegovy in private UK clinics?
Pricing reflects supply costs, manufacturer pricing, clinic overheads, and prescription fees. Mounjaro may cost slightly more at equivalent doses, but prices vary by provider. Cost should not be the only factor — clinical suitability and your prescriber's recommendation are more important.
Which medication is more effective — Wegovy or Mounjaro?
Clinical trials suggest Mounjaro produces slightly more average weight loss (~20.9%) compared to Wegovy (~14.9%), but individual results vary widely. Your prescriber will recommend based on your health profile, not general averages. Effectiveness depends on your response, diet, and activity level.
How long does it take to reach 1mg Wegovy or equivalent Mounjaro dose?
Wegovy takes approximately 4 weeks to reach 1mg (starting at 0.25mg, increasing weekly). Mounjaro takes about 8 weeks to reach 5mg (starting at 2.5mg, increasing every 4 weeks). These schedules allow your body to adjust and help minimise side effects.
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.