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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How To Get Monjaro in the UK
Getting Monjaro (tirzepatide) in the UK involves two main routes: NHS specialist services or private online prescribing. Both pathways require a clinical assessment with a UK-licensed prescriber to confirm you meet eligibility criteria. This guide explains the differences between obtaining Monjaro and Wegovy, how each process works, and what to expect. Use our free GLP-1 weight loss calculator to explore potential outcomes at different doses before speaking to a prescriber about which option suits you.
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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.
Monjaro vs Wegovy — How They Compare
Both Monjaro (tirzepatide) and Wegovy (semaglutide) are prescription-only weekly weight loss injections licensed in the UK, but they work through different mechanisms. Monjaro is a dual GIP and GLP-1 receptor agonist, activating two hormone pathways to help regulate appetite and support weight loss. Wegovy is a GLP-1 receptor agonist only, working through a single mechanism.
Clinical trial outcomes: SURMOUNT-1 data showed Monjaro participants lost an average of 15–20.9% body weight depending on dose (5–15 mg). STEP-1 data showed Wegovy participants lost approximately 14.9% body weight at the maximum 2.4 mg dose. Both achieved results alongside reduced-calorie diet and increased activity. Individual results vary significantly.
Dosing differences: Monjaro starts at 2.5 mg and escalates to a maximum of 15 mg weekly. Wegovy starts at 0.25 mg and escalates to 2.4 mg weekly. The dual mechanism of Monjaro may explain its slightly higher average weight loss in trials, but neither drug assures specific outcomes for any individual.
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.
Getting Monjaro — NHS and Private Routes
NHS route: Monjaro is available through NHS specialist tier 3 weight management services, typically accessed via GP referral. Availability and waiting times vary significantly by region (Integrated Care Board). Some areas have substantial waiting lists. Your GP will assess whether referral is appropriate based on your BMI and health conditions.
Private route: Monjaro is available through GPhC-registered online pharmacies following an online clinical assessment. This route does not require NHS referral and typically offers faster access. Prescriptions are issued by UK-licensed prescribers. Costs range from approximately £250–£320 per month depending on dose.
Either way: A prescriber must assess your individual health, medications, and suitability before issuing a prescription. Both routes are legitimate and legal in the UK. Choose based on your preference for NHS vs private care and your timescale.
- 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.
Can I get Monjaro on the NHS without waiting months?
NHS availability varies by region. Some areas have specialist services with reasonable waiting times; others have lengthy lists. Your GP can advise on local access. Private online prescribing typically offers faster access but involves a cost. Ask your GP whether NHS referral is possible in your area first.
What's the main difference between Monjaro and Wegovy?
Monjaro (tirzepatide) is a dual GIP and GLP-1 receptor agonist; Wegovy (semaglutide) is a GLP-1 agonist only. In clinical trials, Monjaro showed slightly higher average weight loss (15–20.9%) vs Wegovy (14.9%). Both require a prescription and clinical assessment. Individual results vary.
Do I have to choose between Monjaro and Wegovy, or can I switch?
A prescriber may discuss either option based on your health profile and preferences. Some people switch if one medication causes side effects or does not produce desired results. Any switch must be managed by your prescriber — do not change medications without clinical guidance.
What eligibility criteria do I need to meet to get Monjaro?
You typically need a BMI of 30 or above, or 27–29.9 with a weight-related health condition (diabetes, high blood pressure, sleep apnoea, cardiovascular disease). South Asian, Chinese, Black African, or Black Caribbean adults may have lower BMI thresholds (27.5+). A prescriber will assess your individual suitability.
Can I get Monjaro if I'm already taking other medications?
Monjaro can interact with some medications, particularly oral contraceptives and diabetes drugs. You must inform your prescriber of all medications you take. They will assess any interactions and may adjust doses or recommend alternative contraception. Never start Monjaro without a full medication review. ```
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.