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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Can I Buy Mounjaro Online in the UK?
Yes, you can buy Mounjaro online in the UK through licensed prescribing services, but it requires a valid prescription from a UK-registered healthcare professional. Unlike some medications, Mounjaro (tirzepatide) cannot be purchased without a clinical assessment. Both online and NHS routes are available, and choosing between Mounjaro and alternatives like Wegovy depends on your individual health profile and prescriber recommendation. This guide explains how to access these medications safely and what you need to know about eligibility and the prescription process.
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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 to Buy Mounjaro Online vs Wegovy
Buying Mounjaro online in the UK involves completing an online clinical assessment with a UK-licensed prescriber. If approved, your prescription is dispensed by a GPhC-registered pharmacy and delivered to your home. The same process applies to Wegovy (semaglutide), the main alternative GLP-1 weight loss injection available online.
Key differences between Mounjaro and Wegovy:
- Mechanism: Mounjaro is a dual GIP and GLP-1 receptor agonist, while Wegovy is a GLP-1-only agonist
- SURMOUNT trial data: Mounjaro showed average weight loss of 15–21% body weight depending on dose
- STEP trial data: Wegovy showed average weight loss of approximately 15% body weight at maximum dose
- Dosing: Mounjaro ranges from 2.5 mg to 15 mg weekly; Wegovy ranges from 0.25 mg to 2.4 mg weekly
- Cost: Prices vary between providers and doses, typically £129–£320 monthly
Your prescriber will assess which medication suits your individual health profile, medical history, and weight management goals.
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: How to Access Online
NHS access: Mounjaro is available through NHS tier 3 specialist weight management services, but availability varies significantly by region and waiting lists can be lengthy. Referral from your GP to a specialist service is required.
Private online access: You can obtain a prescription without NHS referral by completing an online consultation with a UK-licensed prescriber. Assessment typically takes 24–48 hours. Both Mounjaro and Wegovy are available privately online. To be eligible, you generally need a BMI of 30 or above, or 27 or above with weight-related health conditions such as type 2 diabetes, high blood pressure, or sleep apnoea. Use our free BMI calculator above to check your BMI instantly, and try our GLP-1 weight loss calculator to estimate potential weight loss outcomes with different doses.
Both Mounjaro and Wegovy require a valid prescription and clinical assessment — neither can be purchased without one. The prescriber will review your medical history, current medications, and health conditions before approval. This ensures the medication is safe and appropriate for you. If you're considering either option, discuss with your GP first about eligibility and any NHS alternatives available in your area. Private online prescribing is faster if you meet the eligibility criteria, but NHS access may be available depending on your region and health needs.
- 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 online without a prescription in the UK?
No. Mounjaro is a prescription-only medicine in the UK and cannot be purchased without a valid prescription from a UK-licensed prescriber. All online prescribing services require a clinical assessment before issuing a prescription. This ensures the medication is safe and appropriate for your individual health profile.
Is Mounjaro cheaper online than Wegovy?
Pricing varies between providers and doses. Both Mounjaro and Wegovy typically cost £129–£320 monthly through private online services, depending on the dose. Costs for both medications are similar at comparable doses. Always check current pricing with multiple licensed providers before deciding.
What's the difference between Mounjaro and Wegovy for weight loss?
Mounjaro (tirzepatide) is a dual GIP and GLP-1 receptor agonist, while Wegovy (semaglutide) is a GLP-1-only agonist. In clinical trials, Mounjaro showed slightly higher average weight loss (15–21%) compared to Wegovy (approximately 15%), though individual results vary significantly. Your prescriber will recommend the most suitable option for you.
How long does an online Mounjaro prescription take?
Most online prescribing services complete clinical assessments within 24–48 hours. Once approved, your prescription is dispensed by a GPhC-registered pharmacy and typically delivered within 2–5 working days. NHS access through specialist services may involve longer waiting times depending on your region.
What are the main side effects of Mounjaro compared to Wegovy?
Both medications commonly cause nausea, diarrhoea, vomiting, constipation, and stomach pain, particularly during dose escalation. Mounjaro may cause additional side effects including fatigue and hair loss. Side effects typically decrease over time. Serious side effects are rare but include severe abdominal pain and gallbladder issues — seek immediate medical attention if these occur.
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.