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
How to Get Mounjaro in the UK
Mounjaro (tirzepatide) is a prescription weight loss injection available in the UK through two main routes: NHS specialist services and private online prescribers. Access depends on your BMI, health conditions, and which pathway you choose. The NHS typically requires referral to a tier 3 specialist weight management service, whilst private routes offer faster access following an online clinical assessment. Understanding your options helps you decide which route suits your circumstances and timeline.
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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.
NHS Access vs Private Prescribing Routes
NHS route: Mounjaro is approved by NICE for use in NHS specialist weight management services. You'll need a referral from your GP to a tier 3 or tier 4 specialist service. Eligibility generally requires a BMI of 30 or above, or 27–29.9 with weight-related health conditions (type 2 diabetes, hypertension, sleep apnoea). NHS prescribing varies significantly by region — some areas have long waiting lists of months or years, while others have limited availability. Once approved, the NHS covers all costs.
Private route: You can obtain a Mounjaro prescription through GPhC-registered online pharmacies without NHS referral. You'll complete an online consultation with a UK-licensed prescriber who assesses your suitability. If approved, your prescription is dispensed and delivered. Private costs typically range from £129–£320 monthly depending on dose. This route offers faster access but you pay the full cost.
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.
Mounjaro Kwikpen Dosing and Titration Timeline
Mounjaro comes as a pre-filled KwikPen device containing 4 weekly doses. Treatment starts at 2.5 mg weekly, with dose increases every 4 weeks: 5 mg, 7.5 mg, 10 mg, 12.5 mg, and finally 15 mg as the maximum. Your prescriber may keep you on a lower maintenance dose if you're managing well. Each KwikPen lasts 4 weeks. You inject subcutaneously (under the skin) into your stomach, thigh, or upper arm, rotating sites weekly. Storage requires refrigeration at 2–8°C unopened; after first use, pens can remain at room temperature for up to 30 days.
- 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 difference between getting Mounjaro on the NHS versus privately in the UK?
NHS access requires GP referral to a specialist weight management service and can involve long waiting lists, but treatment is free once approved. Private access is faster — you book an online consultation with a licensed prescriber, receive a prescription if suitable, and pay £129–£320 monthly depending on dose.
Am I eligible for Mounjaro on the NHS in the UK?
Generally, yes, if you have a BMI of 30 or above, or 27–29.9 with weight-related conditions like type 2 diabetes, high blood pressure, or sleep apnoea. South Asian, Chinese, Black African, and Black Caribbean adults may qualify at lower BMI thresholds (27.5+). Your GP assesses eligibility during referral.
How long does the Mounjaro dose titration take?
Full titration to the maximum 15 mg dose takes approximately 20 weeks, as you spend 4 weeks on each dose before increasing. Most people stay at a lower maintenance dose (5–10 mg) if they're achieving good results. Your prescriber decides the final dose based on your response.
Can I switch from Wegovy to Mounjaro in the UK?
Yes, though it requires prescriber guidance. Mounjaro uses a dual GIP and GLP-1 mechanism versus Wegovy's single GLP-1 action, so switching is a clinical decision, not automatic. Approximate dose equivalence exists, but your prescriber will reassess you and may restart titration.
How quickly can I start Mounjaro privately versus NHS in the UK?
Privately, you could have a prescription within days or weeks. NHS timelines vary by region — some specialist services have waiting lists of 6–18 months or longer. If speed is a priority, private prescribing offers much faster access, though at personal cost.
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.