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 Is Mounjaro's Golden Dose and How Does It Compare to Wegovy?
The term "golden dose" for Mounjaro typically refers to the 15mg maintenance dose — the maximum recommended dose in the UK. Unlike Wegovy, which is measured in milligrams as a liquid suspension, each Mounjaro dose comes pre-filled in a KwikPen device. There isn't a standard "ml" measurement for individual doses because each pen is calibrated to deliver a specific mg amount. Understanding how Mounjaro dosing works compared to Wegovy's approach can help you have an informed conversation with your prescriber about which option might suit you.
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.
Mounjaro vs Wegovy: How Dosing and Mechanisms Differ
Mounjaro (tirzepatide) is a dual GIP and GLP-1 receptor agonist — meaning it activates two separate hormone pathways. It's available in five dose strengths: 2.5mg, 5mg, 7.5mg, 10mg, 12.5mg, and 15mg. Each dose is delivered via a pre-filled KwikPen pen, with no liquid measurement needed by the user — you simply press and inject.
Wegovy (semaglutide) is a GLP-1-only agonist, available in doses from 0.25mg to 2.4mg. Wegovy pens also come pre-filled and ready to use.
In the SURMOUNT-1 clinical trial, participants on Mounjaro 15mg (the maximum dose) lost an average of approximately 20.9% of their body weight over 72 weeks. In the STEP-1 trial, Wegovy 2.4mg participants lost an average of approximately 14.9% body weight. Individual results vary significantly, and both medications are used alongside dietary changes and increased physical activity.
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.
Which Is Right for You? A Prescriber Decision
Neither Mounjaro nor Wegovy is "better" — suitability depends on individual health factors, medical history, and how your body responds. Both are prescription-only medicines requiring a clinical assessment before prescribing. Your GP or a licensed prescriber will evaluate your BMI, weight-related health conditions, current medications, and contraindications.
Use our free GLP-1 weight loss calculator to see projected weight loss at different doses, and our BMI calculator to understand where you currently fall on NHS guidelines. However, a prescriber's personalised assessment is essential — they may recommend Mounjaro's dual mechanism for some patients, or Wegovy's single-mechanism approach for others. Cost, availability on the NHS versus private prescription, and personal preference also play a role in the final decision.
- 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.
What does "golden dose" mean for Mounjaro?
"Golden dose" is informal terminology referring to Mounjaro's maximum recommended dose of 15mg weekly. It's called this because clinical trials showed peak efficacy at this dose, with average weight loss around 21%. However, not all patients need or tolerate 15mg — many achieve good results at lower doses with fewer side effects.
Is Mounjaro 15mg the same as Wegovy 2.4mg in strength?
No — they are not directly equivalent because they work via different mechanisms. Mounjaro is a dual GIP+GLP-1 agonist, while Wegovy is GLP-1-only. Trial data suggests Mounjaro 15mg produces slightly greater average weight loss, but individual responses vary. A prescriber will advise which is appropriate for you.
Why doesn't Mounjaro dose come in ml measurements?
Mounjaro comes in pre-filled KwikPen devices calibrated to deliver a specific mg dose in a fixed volume. The user doesn't measure or draw liquid — you simply use the pen as directed. This design reduces dosing errors and makes injection easier for patients compared to a UK pharmacy liquid measurement.
Can you switch from Wegovy to Mounjaro or vice versa?
Switching between GLP-1 medications is possible but must be managed by your prescriber. There is no official established conversion ratio, though clinical guidance suggests approximate equivalences (e.g., Mounjaro 5mg roughly equivalent to Wegovy 0.5mg). Your prescriber will advise on timing and any overlap period.
How do I know if Mounjaro or Wegovy is right for me?
Both require a clinical assessment. Your prescriber will assess your BMI, weight-related health conditions, medical history, allergies, and current medications. Use our free BMI calculator to understand your current status, then discuss options with your GP or a licensed prescriber who can give personalised guidance.
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.