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
Where Can I Buy Mounjaro in the UK?
Mounjaro (tirzepatide) is available in the UK through two main routes: NHS specialist weight management services and private prescription via online consultation. Neither route involves buying Mounjaro over the counter — it is a prescription-only medicine that requires a clinical assessment from a qualified prescriber. This guide explains how to access it, what it costs, and what to expect from each pathway.
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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 Much Does Mounjaro Cost in the UK?
NHS cost: Mounjaro is free on the NHS if prescribed through a specialist tier 3 or tier 4 weight management service, following NICE guidance. However, NHS access varies significantly by region (Integrated Care Board), and waiting lists can be substantial — often several months to over a year in many areas.
Private prescription cost: Private Mounjaro typically ranges from £129 to £280+ per month, depending on the dose and provider. A single Mounjaro KwikPen contains four weekly injections, so costs reflect a four-week supply. Starting doses (2.5 mg) are usually cheaper than maximum doses (15 mg). Many private providers offer dose-escalation packages where you pay a single monthly fee and receive supply as your dose increases over the titration schedule.
- 2.5 mg starter pen: approximately £129–£150
- 5–10 mg maintenance doses: approximately £150–£220
- 15 mg maximum dose: approximately £220–£280
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.
NHS vs Private Access — Which Route Is Right for You?
NHS route: Free but requires GP referral to specialist services and involves waiting lists. Access depends on your regional ICB and meeting NICE eligibility criteria (BMI ≥30 or BMI ≥27–29.9 with weight-related health conditions). Specialist services typically require multiple appointments and ongoing monitoring.
Private route: Faster access — online consultation with a UK-licensed prescriber can be completed within hours. No GP referral needed. You pay privately, but prescription is dispensed by a GPhC-registered pharmacy. Best for those who want immediate access or cannot access NHS services quickly. Use the BMI calculator on this page to check your eligibility, then explore your options.
The private online consultation process is straightforward: complete a medical questionnaire online, a prescriber reviews your health details and eligibility, and if approved, a prescription is issued and sent to a pharmacy. The pharmacy dispenses your Mounjaro KwikPen and posts it to you within a few days. Most private providers also offer follow-up support and dose adjustments. You can use our GLP-1 weight loss calculator to estimate potential weight loss at different doses, which may help you decide whether this treatment is right for you.
- 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 buy Mounjaro without a prescription in the UK?
No. Mounjaro is prescription-only in the UK and cannot be bought over the counter. You must have a prescription from a UK-licensed prescriber — either your GP (via NHS referral) or through a private online consultation. Always ensure any prescriber is registered with the MHRA and GMC.
Is Mounjaro available on the NHS?
Yes, Mounjaro is approved by NICE for use on the NHS through specialist weight management services. However, access varies by region and waiting lists can be long. You typically need a GP referral and BMI ≥30 (or ≥27–29.9 with weight-related health conditions) to qualify.
How long does private prescription Mounjaro take to arrive?
Most private providers dispatch Mounjaro within 2–5 business days of prescription approval. You complete an online consultation, the prescriber assesses your eligibility, issues a prescription, and the pharmacy sends it to your address. Total time from consultation to receiving your KwikPen is typically 3–7 days.
What is the difference between Mounjaro and Wegovy?
Both are prescription-only weight loss injections available in the UK. Mounjaro (tirzepatide) is a dual GIP and GLP-1 receptor agonist, while Wegovy (semaglutide) is a GLP-1 agonist only. Clinical trials show Mounjaro achieved slightly higher average weight loss (~20.9% vs ~14.9%), though individual results vary. Both require clinical assessment and cost similarly on private prescription.
Do I need a GP referral to access private Mounjaro?
No. Private online prescribing does not require a GP referral. You can access private consultation directly without going through your GP. However, if you want NHS access, you will need a GP referral to a specialist weight management service. Your GP can also provide important medical history to the 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.