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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Mounjaro or Wegovy — How to Access in the UK and What They Cost
If you're considering prescription weight loss treatment, you'll likely compare Mounjaro and Wegovy. Both are licensed in the UK, but they differ significantly in how you access them and what you'll pay. This guide explains your options: NHS specialist routes, private online prescribing, typical costs at different doses, and what the clinical assessment involves. Individual eligibility and pricing vary, so understanding the full picture helps you make an informed choice.
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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.
Private Prescription Costs and Access Routes in the UK
Both Mounjaro (tirzepatide) and Wegovy (semaglutide) are available through private UK online prescribing without an NHS referral. Private costs vary by dose and provider, typically ranging from £129 to £320 per month depending on which medication and strength you choose.
Mounjaro private costs: Starting doses (2.5–5 mg) usually cost £129–£180/month, while higher maintenance doses (10–15 mg) range from £220–£320/month. Wegovy private costs: Lower starting doses (0.25–0.5 mg) begin around £129–£150/month, with the maximum 2.4 mg dose typically £250–£300/month. Each prescription requires an online consultation with a UK-licensed prescriber who will assess your eligibility. The consultation fee is often included in the overall monthly cost. Medications are dispensed by GPhC-registered pharmacies, and doses are adjusted over several weeks as part of a structured titration schedule. Individual pricing varies between providers.
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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 Routes — Access, Wait Times, and Eligibility
The NHS route for both medications involves referral from your GP to a specialist tier 3 weight management service. NHS access: Free on prescription if approved by your local integrated care board (ICB), but availability varies significantly by region and wait lists can extend months or longer in many areas. Not all areas fund weight loss injections through the NHS yet.
Private online route: Faster access—typically within days of completing your online assessment—but you pay the full monthly cost. You'll need to complete a health questionnaire and have a brief video or phone consultation with a UK-licensed prescriber who reviews your eligibility based on BMI, health conditions, and current medications. No GP referral is needed. Try our free GLP-1 weight loss calculator to estimate potential results at different doses, and use our BMI calculator to check your current BMI and eligibility criteria.
Key eligibility points: Both medications are licensed for adults with a BMI of 30 or above, or 27–29.9 with weight-related health conditions (type 2 diabetes, hypertension, cardiovascular disease, or sleep apnoea). Adults of South Asian, Chinese, Black African, or Black Caribbean heritage may qualify at slightly lower BMI thresholds. You cannot take either medication if you're pregnant, breastfeeding, under 18, or have a personal or family history of medullary thyroid cancer. Private prescribers conduct similar eligibility checks. The online assessment process is straightforward: answer health questions honestly, declare all current medications, and be clear about any previous weight loss medication use. Once approved, your first prescription and dose titration schedule (typically starting at the lowest dose and increasing weekly or fortnightly) is arranged. Use our weight converter to understand your current weight in different units (kg, stone, lbs) as part of your assessment preparation.
- 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 or Wegovy cheaper on the NHS or private?
On the NHS, both are free once prescribed through a specialist service—but access is limited and varies by region with potentially long waiting lists. Privately, monthly costs range from £129–£320 depending on medication and dose. Private access is faster but you pay the full cost yourself. NHS access, when available, is ultimately cost-free but availability is postcode-dependent.
How long does an online private consultation take?
Most UK online consultations for weight loss injections take 10–20 minutes. You'll complete a health questionnaire beforehand, then have a brief video or phone consultation with a UK-licensed prescriber who reviews your answers, checks your eligibility, and discusses the medication. They'll ask about current medications, allergies, and weight loss goals. If approved, your prescription and first supply are usually arranged within 24–48 hours.
Do I need my GP's permission to get a private prescription?
No. Private online prescribing is independent—you do not need a GP referral or permission. However, it's good practice to inform your GP that you're starting weight loss medication, especially if you take other medications like diabetes drugs, blood pressure medication, or oral contraceptives, as some interactions are possible and your GP can help monitor your progress.
What's the difference between Mounjaro and Wegovy pricing?
Both are similarly priced on the private market, ranging £129–£320/month depending on dose. Mounjaro typically starts at 2.5 mg (around £130–£160/month) and titrates to 15 mg maximum (£280–£320/month). Wegovy starts at 0.25 mg (around £129–£150/month) and titrates to 2.4 mg (£250–£300/month). Final costs depend on your prescriber and which dose you stabilise on. Compare with our GLP-1 weight loss calculator to see projected outcomes at each dose level.
If I start private, can I switch to NHS?
This varies by region and local ICB policy. Some NHS services may not accept patients already on private weight loss medication, while others might. If you're considering NHS access after private treatment, contact your local specialist weight management service or ask your GP. Eligibility and policy differ across England, Scotland, Wales, and Northern Ireland, so check your local NHS options early.
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.