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
Can Your GP Prescribe Mounjaro in the UK?
The short answer is: your GP can technically prescribe Mounjaro (tirzepatide), but in practice, most UK GPs do not initiate weight loss injections in primary care. Instead, Mounjaro is typically prescribed through specialist NHS tier 3 weight management services or via private online prescribing. NICE has approved tirzepatide for use within the NHS, but access varies significantly by region and waiting times can be substantial. Understanding your options — whether through the NHS or private prescription — is key to accessing this weight loss injection.
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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.
How Does Mounjaro Prescription Work in the UK?
NHS route: Your GP cannot usually start Mounjaro treatment directly. Instead, they can refer you to a specialist tier 3 or tier 4 weight management service if you meet eligibility criteria (BMI 30 or above, or BMI 27–29.9 with weight-related health conditions). These specialist services include a multidisciplinary team — doctors, dietitians, and therapists — who assess whether Mounjaro is appropriate for you. Once approved, the specialist service prescribes and manages your treatment, not your GP. Waiting lists for NHS tier 3 services vary enormously by region — some areas have waiting times of several months to over a year.
Private route: You can access Mounjaro privately through a UK-registered online prescriber without an NHS referral. You complete an online consultation, a licensed prescriber reviews your health details, and if approved, issues a prescription that a GPhC-registered pharmacy dispenses. This route is faster but involves private costs (typically £150–£300+ per month depending on dose).
Use our GLP-1 weight loss calculator to explore projected outcomes at different Mounjaro doses, and check your BMI using our free BMI calculator to understand your eligibility.
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.
GP Role in Mounjaro Treatment
Your GP's role in Mounjaro treatment is typically supportive rather than prescriptive. They can:
- Discuss weight management options and refer you to specialist services
- Provide baseline health checks before referral
- Monitor your general health during treatment if you're on the NHS pathway
- Manage any interactions with other medications you're taking
- Offer lifestyle support and dietary advice alongside medication
If you're accessing Mounjaro privately, your GP can still be involved in monitoring your health, though they won't prescribe or manage the Mounjaro itself. Some GPs are supportive of private weight loss medication; others may have concerns. Communication between your private prescriber and your GP is valuable but not automatic.
- 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.
Will my NHS GP prescribe Mounjaro directly?
Unlikely. Most NHS GPs do not initiate Mounjaro prescriptions in primary care. You'll need referral to a specialist tier 3 weight management service. Your GP can make this referral if you meet eligibility criteria and your local NHS service offers it, but availability varies significantly by region.
How do I get Mounjaro on the NHS?
Ask your GP for a referral to your local tier 3 or tier 4 weight management service. You must meet eligibility criteria: BMI 30+ or BMI 27–29.9 with weight-related conditions like type 2 diabetes, hypertension, or sleep apnoea. NICE approved tirzepatide for NHS use, but specialist assessment is required before prescription.
How long are NHS waiting lists for Mounjaro?
Waiting times vary widely by region and local NHS availability. Some areas have waits of 3–6 months, while others may have longer delays or no current availability. Contact your local integrated care board (ICB) or ask your GP for realistic timescales in your area.
Can I buy Mounjaro privately without NHS referral?
Yes. Private online prescribing is available through UK-licensed prescribers and GPhC-registered pharmacies. You complete an online health assessment, and if approved, receive a prescription. This is faster than NHS but involves private costs typically ranging from £150–£300+ monthly depending on dose.
Is Mounjaro the same as Ozempic?
Both contain similar mechanisms but are different medications. Mounjaro (tirzepatide) is a dual GIP and GLP-1 agonist approved specifically for weight management. Ozempic (semaglutide) is approved for type 2 diabetes. Wegovy (also semaglutide) is the licensed UK weight management injection. Always ensure you're prescribed the correct formulation for your intended use.
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.