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 Wegovy Dose Equals Mounjaro 7.5?
Mounjaro 7.5mg (tirzepatide) and Wegovy are not directly equivalent because they work differently — Mounjaro is a dual GIP and GLP-1 receptor agonist, while Wegovy is a GLP-1 agonist only. However, clinical experience suggests that Mounjaro 7.5mg has roughly similar weight loss effects to Wegovy 1.7mg. This guide explains the approximate equivalence, NHS eligibility, and how to access both medications in the UK.
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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 NHS Context
Mounjaro 7.5mg is approximately equivalent to Wegovy 1.7mg based on clinical trial data and prescribing experience, though individual responses vary significantly. Mounjaro, containing tirzepatide, activates two hormone pathways (GIP and GLP-1), while Wegovy's semaglutide works on GLP-1 alone — meaning direct comparison is not precise.
- Mounjaro 5mg: roughly equivalent to Wegovy 0.5mg
- Mounjaro 10mg: roughly equivalent to Wegovy 1.7mg
- Mounjaro 15mg: roughly equivalent to Wegovy 2.4mg
In the SURMOUNT-1 trial, Mounjaro 7.5mg achieved average weight loss of approximately 18% of body weight at 72 weeks. In the STEP-1 trial, Wegovy 1.7mg achieved similar outcomes. However, these are trial averages — clinical practice shows some patients respond better to one medication than the other. Neither medication should be switched without your prescriber's guidance, as the dose escalation schedules differ (Mounjaro requires minimum 4 weeks per dose versus Wegovy's escalation pathway).
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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.
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NHS Eligibility and UK Prescribing Routes
Both Mounjaro and Wegovy require a BMI of 30 or above, or 27–29.9 with weight-related health conditions (type 2 diabetes, hypertension, cardiovascular disease, obstructive sleep apnoea). On the NHS, access is through tier 3 specialist weight management services following referral from your GP — availability and waiting times vary significantly by region.
Privately, both medications are available through online clinical assessments with UK-licensed prescribers, dispensed by GPhC-registered pharmacies. Private costs typically range from £129–£320 monthly depending on dose. Neither medication assures weight loss; results depend on adherence, diet, and physical activity. Use our free GLP-1 weight loss calculator to estimate potential outcomes, and our BMI calculator to check your eligibility baseline.
- 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 Mounjaro 7.5mg more effective than Wegovy 1.7mg?
Clinical trials show similar average weight loss at these doses (approximately 18%), but individual results vary. Mounjaro's dual mechanism may work better for some people; Wegovy's single mechanism suits others. Your prescriber will recommend based on your health profile.
Can I switch from Mounjaro to Wegovy at equivalent doses?
You should not switch doses yourself. If considering a switch, your prescriber will assess whether it's appropriate and may recommend a different dose on Wegovy, as the medications have different escalation schedules and mechanisms.
How long until I see weight loss on these injections?
Most people notice appetite reduction within days to weeks. Weight loss typically becomes measurable within 4–8 weeks. Full benefits at any dose usually appear after 12–16 weeks of consistent use alongside reduced-calorie diet and physical activity.
What's the difference between Mounjaro and Wegovy mechanisms?
Mounjaro (tirzepatide) activates GIP and GLP-1 receptors — two hormone pathways that regulate appetite and blood sugar. Wegovy (semaglutide) activates GLP-1 only. The dual action may explain why some clinical trials show slightly higher average weight loss with Mounjaro.
How do I access Mounjaro or Wegovy on the NHS in the UK?
Ask your GP for referral to your local tier 3 specialist weight management service. Eligibility is assessed against BMI and comorbidities. Waiting lists vary by region (ICB). Private options are faster but require self-funding through online clinical consultations.
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.