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
What Is Mounjaro and How Can You Access It in the UK?
Mounjaro is a prescription-only weight management injection containing tirzepatide, approved in the UK for adults with obesity or overweight with related health conditions. It's a once-weekly injection that works as a dual GIP and GLP-1 receptor agonist — different from other weight loss injections like Wegovy, which is GLP-1 only. In the UK, you can access Mounjaro through NHS specialist services or private online prescribing, though availability and cost vary significantly. Understanding how to access it and what it costs is essential before considering treatment.
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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 and How Do You Get It?
Mounjaro costs vary depending on where and how you access it. On the NHS, the medication itself is free once prescribed through a tier 3 specialist weight management service, though you may wait several months for an appointment depending on your region. Through private online prescribing, costs typically range from £180 to £300 per month depending on your dose and the provider. Each KwikPen contains 4 weeks of doses, so a monthly supply is standard. The cost reflects the specific dose you're prescribed — starting doses (2.5 mg) are often cheaper than maximum doses (15 mg). You'll also need to factor in the cost of the clinical assessment, which ranges from £30 to £80 with most private providers. Unlike some weight loss medications, there are currently no NHS prescriptions available through standard GP services — Mounjaro access is restricted to specialist NHS services or private prescribing following a clinical assessment with a UK-licensed prescriber.
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 medication but typically requires referral from your GP to a specialist tier 3 weight management service. Waiting times can be 6–18+ months in many areas, and not all regions have equal access. Once on NHS Mounjaro, you're supported by specialist dietitians and doctors, but your prescriber controls dose escalation.
Private route: Faster access (often within days) through an online consultation with a UK-licensed prescriber. No GP referral needed. You have more choice of provider and often more flexible dose management. However, you pay for both the clinical assessment and the medication. Private online consultations typically take 15–30 minutes and assess your eligibility, medical history, and weight loss goals. Use our free GLP-1 weight loss calculator to estimate potential results at different doses before starting treatment.
- 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 available on the NHS?
Yes, Mounjaro is available on the NHS through specialist tier 3 weight management services, but not through standard GP prescription. You'll need a GP referral and will typically wait several months for an appointment. Once prescribed, the medication is free, though specialist support is included.
How much does a private Mounjaro prescription cost per month?
Private Mounjaro costs approximately £180–£300 per month depending on your dose, plus the initial clinical assessment fee (£30–£80). Starting doses are cheaper than maximum doses. Prices vary by provider, so it's worth checking current rates.
Can my GP prescribe Mounjaro directly?
No, standard GPs cannot prescribe Mounjaro for weight management in the UK — it's restricted to NHS specialist weight management services or private prescribers. If interested in NHS access, ask your GP for a referral to your local tier 3 weight management service.
What's the difference between Mounjaro and Wegovy in terms of access?
Both require prescriptions and clinical assessment, but Mounjaro uses tirzepatide (dual GIP/GLP-1 mechanism) while Wegovy uses semaglutide (GLP-1 only). Availability and costs differ by provider. Our weight loss calculator can help you compare potential results between different medications.
How quickly can I start private Mounjaro treatment?
Private online prescribing is typically much faster than NHS access — you can often have a clinical consultation and prescription within 1–7 days. NHS access through specialist services usually involves a waiting list of several months depending on your region and local demand.
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.