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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Is Mounjaro Going Up In Price — What You Need to Know
Mounjaro pricing in the UK has been a common concern since its approval for weight management. The cost of Mounjaro depends on your prescription route — NHS access or private — and can vary by dose. This guide compares Mounjaro pricing with Wegovy, explains the mechanisms behind each medication, and helps you understand which might suit you based on clinical evidence and individual factors. Both require a clinical assessment before prescription, and individual results vary significantly.
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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: Mechanism, Trials, and Effectiveness
Mounjaro (tirzepatide) is a dual GIP and GLP-1 receptor agonist, meaning it activates two natural hormone pathways. In the SURMOUNT-1 clinical trial, participants taking Mounjaro 15 mg lost an average of 20.9% of body weight over 72 weeks, alongside reduced-calorie diet and increased physical activity.
Wegovy (semaglutide) is a GLP-1 receptor agonist only, activating a single pathway. The STEP-1 trial showed average weight loss of approximately 14.9% body weight at 68 weeks on the maximum dose of 2.4 mg.
Both are prescription-only medicines requiring a clinical assessment. Neither is assured to work, and both work best alongside lifestyle changes. Use our GLP-1 weight loss calculator to project potential results at different doses — results vary between individuals.
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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.
Pricing, Eligibility, and Choosing Between Them
Mounjaro typically costs between £129–£320 per month privately, depending on dose. Wegovy costs similarly. NHS access for both is through specialist tier 3 weight management services, though availability and waiting times vary significantly by region — some areas have long waiting lists.
Eligibility for either medication is the same: BMI 30 or above, or BMI 27–29.9 with weight-related health conditions. Your GP or prescriber will assess your individual situation, medical history, and preferences. Neither medication is universally "better" — suitability depends on your health profile, tolerability, and how your body responds. A prescriber will help you decide which is appropriate for you.
Mounjaro KwikPen is a once-weekly injection starting at 2.5 mg and titrating to a maximum of 15 mg. Wegovy is also once-weekly but starts at 0.25 mg and titrates to 2.4 mg. Mounjaro's higher doses reflect its dual-mechanism design. Check your current BMI using our BMI calculator, and discuss with your prescriber which medication aligns best with your health goals and medical history.
- 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 more expensive than Wegovy in the UK?
Privately, both cost similarly — roughly £129–£320 per month depending on dose and provider. NHS access for both is through specialist weight management services and is free at the point of use, though availability varies by region and waiting times can be long.
What's the main difference between Mounjaro and Wegovy?
Mounjaro (tirzepatide) is a dual GIP+GLP-1 agonist activating two hormone pathways. Wegovy (semaglutide) activates GLP-1 only. Clinical trials showed Mounjaro produced slightly higher average weight loss, but individual results vary significantly.
Can my GP prescribe Mounjaro directly, or do I need a specialist?
NHS prescription typically requires referral to a specialist tier 3 weight management service. Private prescription is available through GPhC-registered online pharmacies following a clinical assessment by a UK-licensed prescriber — you don't need an NHS referral for private access.
Which medication is better for weight loss — Mounjaro or Wegovy?
Both are effective. SURMOUNT trials showed Mounjaro 15 mg achieved ~21% average weight loss, while STEP trials showed Wegovy 2.4 mg achieved ~15% average weight loss. However, individual results vary, and the "best" choice depends on your health profile, tolerability, and prescriber recommendation.
Am I eligible for either Mounjaro or Wegovy?
Both require BMI 30 or above, or BMI 27–29.9 with at least one weight-related health condition (type 2 diabetes, high blood pressure, heart disease, sleep apnoea). A prescriber will assess your individual eligibility and suitability based on your full medical history.
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.