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 I Buy Mounjaro Over The Counter in the UK?
No, Mounjaro (tirzepatide) is a prescription-only medicine in the UK and cannot be bought over the counter. You'll need a prescription from a licensed healthcare professional following a clinical assessment. You can access Mounjaro through two routes: the NHS (via specialist weight management services) or privately through online consultations with UK-licensed prescribers. Both routes require evidence that you meet the eligibility criteria for weight management treatment. Check your BMI using our free BMI calculator above to see where you fall on the NHS eligibility scale.
10,000+ calculations today · NHS-aligned thresholds · 100% free
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.
What Does Prescription-Only Mean for Mounjaro?
Prescription-only means Mounjaro cannot be obtained without a formal prescription from a UK-licensed doctor or specialist prescriber. This is because tirzepatide is a potent medication requiring proper medical assessment before use. The prescriber will review your medical history, current medications, and eligibility before deciding if it's suitable for you. You'll also need to complete health screening questions about any family history of thyroid cancer, pancreatitis, or other contraindications. Mounjaro is supplied as a pre-filled KwikPen device containing four once-weekly injections. The prescription must come from either an NHS specialist weight management service (tier 3) or a private online prescriber registered with the General Pharmaceutical Council (GPhC). You cannot buy Mounjaro from overseas without a UK prescription, as it's not legal to import prescription medications without proper authorisation.
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 Routes — Cost and Timeline
NHS route: Available through tier 3 specialist weight management services via GP referral. Free on prescription once approved, but waiting lists can be lengthy (months to years in many regions). Access varies significantly by region and depends on local integrated care board (ICB) funding decisions. NICE has approved tirzepatide for NHS use, but availability remains inconsistent. Private route: Available through GPhC-registered online pharmacies following a consultation with a UK-licensed prescriber. Costs typically range from £129–£320 per month depending on your dose and provider. Private access is faster (often within days) but you pay the full cost. Many people use our free GLP-1 weight loss calculator to compare projected outcomes before committing to private 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 without a prescription in the UK?
No. Mounjaro is a prescription-only medicine and cannot be bought over the counter or without a valid prescription from a licensed UK prescriber. Any supplier offering Mounjaro without requiring a prescription is operating illegally.
How much does Mounjaro cost privately in the UK?
Private costs typically range from £129 to £320 per month depending on your dose and the provider. Starting doses (2.5 mg) cost less than maximum doses (15 mg). Costs vary between private prescribing services, so it's worth comparing.
Can I get Mounjaro on the NHS?
Yes, through tier 3 specialist weight management services if you meet eligibility criteria (BMI ≥30, or ≥27 with weight-related health conditions). You need a GP referral. Availability and waiting times vary significantly by region.
What happens during a private online consultation for Mounjaro?
You'll complete a detailed health questionnaire, declare any medical conditions and medications, and may have a video or telephone call with a prescriber. If approved, a prescription is issued to a GPhC-registered pharmacy, which dispenses and delivers your medication.
How do I know if I'm eligible for Mounjaro?
Eligibility requires a BMI of 30 or above, or 25–29.9 with weight-related health conditions (type 2 diabetes, high blood pressure, sleep apnoea, etc). Use our free BMI calculator above to check your personal BMI and see where you stand on the eligibility scale.
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.