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 is Equivalent to Mounjaro 7.5mg?
When comparing Mounjaro (tirzepatide) and Wegovy (semaglutide) for weight management, there is no exact dose-for-dose equivalence because they work through different mechanisms. However, clinical evidence suggests that Mounjaro 7.5mg is approximately equivalent to Wegovy 1.7mg in terms of expected weight loss outcomes. Both are prescription-only GLP-1 receptor agonist medications licensed in the UK, but they differ in their pharmacology and individual results vary significantly. This guide explains the approximate equivalence, how each medication works, and what to expect from each dose level.
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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 Mounjaro and Wegovy Compare at These Doses
Mounjaro (tirzepatide) 7.5mg is a dual GIP and GLP-1 receptor agonist — it activates two separate hormone pathways to support appetite regulation and weight loss. In the SURMOUNT clinical trials, participants on tirzepatide 7.5mg saw average weight loss of approximately 19.5% of their body weight over 72 weeks, alongside reduced-calorie diet and increased physical activity.
Wegovy (semaglutide) 1.7mg is a GLP-1 receptor agonist only — it activates a single pathway. In the STEP clinical trials, semaglutide 1.7mg typically resulted in weight loss of approximately 14–15% of body weight. The approximate equivalence between these doses reflects similar weight loss outcomes in clinical settings, though individual results vary considerably.
- Mounjaro requires dose titration from 2.5mg over 20+ weeks to reach 7.5mg
- Wegovy titration takes 16 weeks to reach 1.7mg maintenance
- Both are once-weekly injections delivered via pre-filled pens
- Both require a prescription and clinical assessment before starting
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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.
Side Effects and Practical Considerations
Both medications commonly cause gastrointestinal side effects including nausea, diarrhoea, vomiting, and constipation — these typically decrease over time as your body adjusts. Serious side effects are rare but include severe abdominal pain (possible pancreatitis) and gallbladder problems, which require immediate medical attention. When switching between Mounjaro and Wegovy, any change must be managed by your prescriber. A GP or licenced prescriber will assess your individual health, eligibility, and which medication is most suitable for you based on your medical history, current medications, and weight loss goals. Individual responses to each medication vary, so the dose equivalent for one person may differ from another in terms of actual weight loss achieved.
- 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.
Why isn't there a precise Mounjaro to Wegovy dose equivalence?
Mounjaro and Wegovy use different mechanisms — Mounjaro is a dual GIP/GLP-1 agonist, while Wegovy is GLP-1 only. This means they affect the body differently, so a simple mg-for-mg conversion doesn't apply. Approximate equivalences are based on clinical trial weight loss outcomes, not on identical pharmacology.
Can I switch from Mounjaro 7.5mg to Wegovy 1.7mg?
Any switch between medications must be managed by your prescriber. They will assess whether switching is appropriate for you, consider any missed doses or timing issues, and potentially adjust your dose when moving to a different medication. Never switch without medical guidance.
Which medication causes fewer side effects at these doses?
Side effects are similar between both medications — nausea and gastrointestinal symptoms are very common. Individual tolerance varies significantly. Your prescriber will monitor your response and can adjust your dose or recommend strategies to manage side effects.
How do I access Mounjaro 7.5mg or Wegovy 1.7mg in the UK?
Both are prescription-only and available through NHS specialist weight management services (tier 3) or private online prescribing following a clinical assessment. NHS access varies by region. Private access is available through GPhC-registered pharmacies with a prescription from a licensed UK prescriber.
Can I use the GLP-1 calculator to compare weight loss between these doses?
Yes — our free GLP-1 weight loss calculator can help you explore projected weight loss outcomes at different doses of both medications. The calculator uses clinical trial data to give you an estimate, though remember individual results vary based on diet, activity, and personal factors.
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.