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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Wegovy and Mounjaro Dose Comparison — UK Cost and Access
Wegovy and Mounjaro are both prescription-only weight loss injections available in the UK, but they differ in dose ranges, pricing, and how you can access them. Mounjaro (tirzepatide) uses a different dual-mechanism approach compared to Wegovy's single GLP-1 pathway, and this affects both dosing schedules and cost. Whether you're accessing either medication through the NHS or privately, understanding the dose comparison and pricing landscape will help you make an informed decision about which route suits your circumstances.
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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.
Dose Comparison and UK Private Prescription Costs
Mounjaro (tirzepatide) starts at 2.5 mg weekly and escalates through 5 mg, 7.5 mg, 10 mg, 12.5 mg, to a maximum of 15 mg. Wegovy (semaglutide) begins at 0.25 mg weekly, stepping up through 0.5 mg, 1 mg, 1.7 mg, to a maximum of 2.4 mg. The mounjaro KwikPen delivers four weekly doses per pen, while Wegovy pens also contain a four-week supply.
Private prescription costs in the UK typically range from £129–£320 per month depending on the dose and provider, with Mounjaro generally available in the £180–£280 range for maintenance doses (10–15 mg), and Wegovy around £180–£250 for the maximum 2.4 mg dose. These prices reflect the private online consultation fee, prescriber assessment, and pharmacy dispensing. Lower doses cost less, and prices vary between GPhC-registered pharmacies. Neither medication is routinely available on the NHS outside specialist tier 3 weight management services, and NHS access involves significant regional variation and waiting lists that can extend months or years.
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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 and Getting Started
The NHS route requires a referral from your GP to a specialist tier 3 weight management service, where you'll be assessed for eligibility under NICE guidance—typically BMI 30 or above, or BMI 27–29.9 with weight-related health conditions. Private access is faster: you complete an online consultation with a UK-licensed prescriber, and if approved, your prescription is dispensed by a GPhC-registered pharmacy within days. The online assessment asks about your medical history, current medications, and weight management goals. You'll need to provide your height, current weight, and any existing health conditions like diabetes or hypertension. Once prescribed, you inject yourself weekly at home, rotating injection sites (abdomen, thigh, or upper arm). Individual results vary significantly—use our free GLP-1 weight loss calculator to explore projected outcomes at different doses alongside your GP or prescriber's guidance.
- 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.
What's the main dose difference between Wegovy and Mounjaro?
Mounjaro's maximum dose is 15 mg weekly, whilst Wegovy's is 2.4 mg weekly. They're not directly comparable doses because Mounjaro uses a dual GIP+GLP-1 mechanism and Wegovy uses GLP-1 only. Clinical trial data show Mounjaro achieved approximately 20.9% average weight loss at maximum dose, whilst Wegovy achieved around 14.9%. However, individual results vary significantly.
How much does Wegovy cost privately in the UK?
Private Wegovy typically costs £180–£250 per month for the maximum 2.4 mg dose through GPhC-registered online pharmacies, including the consultation fee and pharmacy dispensing. Lower doses cost less. Prices vary between providers, so it's worth comparing. Private access is faster than NHS routes but not funded by the health service.
Can I get Mounjaro on the NHS?
Mounjaro is available through specialist NHS tier 3 weight management services if you meet NICE eligibility criteria (BMI 30 or above, or BMI 27–29.9 with health conditions like diabetes). However, NHS availability varies significantly by region, and waiting lists are lengthy in many areas. Your GP can refer you to your local service.
What happens during an online private consultation?
You'll complete a health questionnaire covering your medical history, medications, height, weight, and weight loss goals. A UK-licensed prescriber reviews this and assesses whether the medication is suitable for you. If approved, a prescription is issued to a GPhC-registered pharmacy for dispensing. The process typically takes 24–48 hours from consultation to delivery.
Do Wegovy and Mounjaro require different injection techniques?
Both are once-weekly subcutaneous injections using pre-filled pens. You inject into the abdomen, thigh, or upper arm, rotating sites weekly. Mounjaro uses a KwikPen device, Wegovy uses an auto-injection pen. Your prescriber or pharmacist will provide injection training, and instructional videos are available online. Technique is the same for both.
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.