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
7.5mg Mounjaro in ml vs Wegovy — What's the Difference?
The 7.5mg dose of Mounjaro (tirzepatide) represents the second escalation step in UK treatment plans, typically reached around week 9–12 of therapy. If you're comparing this dose to Wegovy (semaglutide), it's important to understand that these are two different weight loss medications with distinct mechanisms, dosing schedules, and clinical evidence. This guide explains the key differences, trial data, and how your GP or prescriber will decide which is suitable for you. Both are prescription-only medicines requiring clinical assessment before dispensing.
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.
How Mounjaro 7.5mg Compares to Wegovy — Mechanism and Trial Data
Mounjaro (tirzepatide) is a dual GIP and GLP-1 receptor agonist, meaning it activates two natural hormone pathways simultaneously. This dual mechanism may offer a different weight loss profile compared to Wegovy's single GLP-1 pathway. In the SURMOUNT-1 clinical trial, participants on 7.5mg Mounjaro (or escalating to higher doses) achieved average weight loss of approximately 19.5% of body weight over 72 weeks, alongside a reduced-calorie diet and increased physical activity.
Wegovy (semaglutide) is a GLP-1-only agonist, activating a single hormone pathway. The STEP-1 trial showed average weight loss of approximately 14.9% of body weight at the maximum 2.4mg dose. The key distinction: Mounjaro's dual mechanism (GIP plus GLP-1) may produce greater appetite suppression in some individuals, though individual results vary significantly. Neither medication assures weight loss, and outcomes depend on diet, activity, dose tolerance, and personal physiology.
- Mounjaro 7.5mg: escalation dose, typically reached week 9–12
- Wegovy equivalent: approximately 1.7mg (though no official conversion exists)
- Both require clinical assessment and prescription
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.
Eligibility, NHS Access, and Choosing Between Them
Both Mounjaro and Wegovy are available in the UK for adults with a BMI of 30 or above, or BMI 27–29.9 with weight-related health conditions such as type 2 diabetes, hypertension, or cardiovascular disease. NHS access is through specialist tier 3/4 weight management services — availability and waiting times vary significantly by region. Private access is available via GPhC-registered online pharmacies following a clinical assessment with a UK-licensed prescriber.
Your prescriber will assess which medication suits your individual health profile, medical history, and tolerance to side effects. Some patients tolerate the dual mechanism of Mounjaro better; others respond well to Wegovy's simpler mechanism. Neither is universally superior — suitability is personal. Use our free GLP-1 weight loss calculator to estimate potential outcomes at different doses, and discuss eligibility with your GP or prescriber.
- 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.
How many ml is a 7.5mg Mounjaro dose?
Each Mounjaro KwikPen delivers a fixed dose by volume, but the ml measurement varies by pen concentration. A 7.5mg dose contains approximately 1.5ml of solution in the standard Mounjaro pen. However, you don't measure or draw the dose yourself — the pre-filled pen automatically delivers the correct 7.5mg when you inject. Your pharmacy will provide the correct pen for your dose level.
Is Mounjaro 7.5mg better than Wegovy?
No single medication is universally "better" — suitability depends on your individual health, medical history, and how your body responds. Clinical trials show Mounjaro achieved higher average weight loss (19.5% vs 14.9% for Wegovy), but individual results vary considerably. Your prescriber will recommend the most appropriate option based on your clinical assessment, not on trial averages.
Can you switch from Mounjaro 7.5mg to Wegovy?
Yes, switching is possible but must be managed by your prescriber. There is no official conversion chart between the two medications. A rough guide places 7.5mg Mounjaro at approximately 1.7mg Wegovy equivalence, but any switch requires clinical oversight to ensure safe transition and appropriate monitoring of your weight loss progress.
How long does it take to reach 7.5mg Mounjaro?
The standard UK titration schedule reaches 7.5mg around week 9–12. You start at 2.5mg (weeks 1–4), escalate to 5mg (weeks 5–8), then 7.5mg (weeks 9–12+), provided you tolerate each dose. If you experience side effects or need slower escalation, your prescriber may extend the timeline. Minimum 4 weeks on each dose before escalating.
Are Mounjaro side effects worse at 7.5mg than lower doses?
Side effects can be dose-dependent — some users experience more nausea, diarrhoea, or stomach discomfort at higher doses. However, tolerance often improves over weeks 2–4 at each new dose level. Common side effects include nausea, diarrhoea, vomiting, and constipation. Serious side effects are rare but require urgent medical attention (severe stomach pain, allergic reactions). Discuss any concerns with your prescriber. ---
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.