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
Insulin Resistance and Mounjaro in the UK
Insulin resistance is a metabolic condition where your body doesn't respond properly to insulin, increasing risk of type 2 diabetes and weight gain. Mounjaro (tirzepatide) is a prescription-only weight management injection that may help support weight loss and improve insulin sensitivity in eligible UK adults. This guide explains how to access Mounjaro in the UK, what it costs, and whether you might be eligible based on your health profile.
10,000+ calculations today ยท NHS-aligned thresholds ยท 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/mยฒ).
While BMI isn't a perfect measure โ it doesn't account for muscle mass, bone density, or fat distribution โ 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 โ 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 vs Private Access to Mounjaro in the UK
NHS access: Mounjaro is available through specialist tier 3 and tier 4 weight management services. You'll need a GP referral, and eligibility depends on your BMI, weight-related health conditions (including type 2 diabetes or prediabetes), and your local Integrated Care Board (ICB) commissioning decisions. NHS waiting lists for specialist services vary significantly across regions โ some areas have waiting times of several months or longer. Once approved through the NHS, Mounjaro is provided at no cost to you.
Private access: Mounjaro is available through GPhC-registered online pharmacies following a private clinical assessment with a UK-licensed prescriber. Private prescription costs typically range from ยฃ140 to ยฃ320 per month depending on your dose (tirzepatide doses range from 2.5 mg to 15 mg weekly). You don't need an NHS referral โ you can access private prescriptions directly. The Mounjaro KwikPen comes pre-filled with 4 weeks' supply of injections.
Individual circumstances vary; your GP can advise which route is most appropriate for you.
Clinically BackedWeight Loss
No appointments. No waiting rooms. Just care โ 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 โ 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 โ completely free.
Online Prescription Process and What to Expect
Private prescribing for weight management in the UK follows a structured clinical assessment. You'll typically complete an online health questionnaire covering your medical history, current medications, BMI, and weight-related health conditions. A registered UK prescriber reviews your information and decides whether Mounjaro is suitable based on NICE guidance and clinical appropriateness. If approved, your prescription is sent to a GPhC-registered pharmacy, which dispenses your Mounjaro KwikPen. Most first orders arrive within 2โ5 working days. You'll receive guidance on injection technique, storage (refrigerate until use, then room temperature for up to 30 days), and when to contact your prescriber if you experience side effects.
Use our free GLP-1 weight loss calculator to estimate potential outcomes at different Mounjaro doses, and check your starting point with our BMI calculator.
- 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 โ 5mg โ 7.5mg โ 10mg โ 12.5mg โ 15mg
- GLP-1 receptor agonist
- Up to 15โ17% body weight loss (STEP trials)
- Weekly injection, 5-step dose escalation
- NHS & private prescription available
- Doses: 0.25mg โ 0.5mg โ 1mg โ 1.7mg โ 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 | 15โ22.5% | 12โ17% |
| Key trial | SURMOUNT-1 (2022) | STEP 1 (2021) |
| Max dose | 15 mg weekly | 2.4 mg weekly |
| Escalation period | 20โ32 weeks | 16โ20 weeks |
| Administration | Weekly injection (pen) | Weekly injection (pen) |
| NHS availability | Private prescription only | NHS & private |
| Approx. private cost | ยฃ150โยฃ250/month | ยฃ150โยฃ300/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 โ 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.
Does insulin resistance make weight loss harder?
Yes. Insulin resistance often causes increased appetite, reduced fat burning, and easier fat storage โ making weight loss more challenging. Mounjaro may help by improving how your body uses insulin and reducing appetite. However, individual responses vary. Your GP can assess whether prescription weight loss support is appropriate for your specific situation.
How much does Mounjaro cost privately in the UK?
Private Mounjaro costs typically range from ยฃ140 to ยฃ320 per month depending on your dose. The starting dose (2.5 mg) is usually at the lower end; higher maintenance doses (10โ15 mg) cost more. Prices vary slightly between GPhC-registered providers. Always check the total cost including the prescription fee before ordering.
Can I get Mounjaro free on the NHS if I have insulin resistance?
Mounjaro may be available on the NHS if you meet NICE criteria: BMI of 30 or above, or 27โ29.9 with weight-related health conditions such as type 2 diabetes, prediabetes, or cardiovascular disease. Access is through specialist tier 3 weight management services via GP referral. Availability and waiting times vary significantly by region.
What's the difference between Mounjaro and Wegovy for insulin resistance?
Mounjaro (tirzepatide) is a dual GIP and GLP-1 receptor agonist; Wegovy (semaglutide) is a GLP-1 agonist only. Both are prescription-only for weight management. Mounjaro may work differently due to its dual mechanism. Clinical trials showed Mounjaro resulted in average weight loss of 15โ21%, though individual results vary. Your prescriber can advise which is more suitable.
How quickly will I see results with Mounjaro?
Weight loss with Mounjaro typically becomes noticeable after 4โ8 weeks, though individual timelines vary. Dose increases happen every 4 weeks, starting at 2.5 mg and escalating to a maintenance dose (usually 10โ15 mg). Results depend on your diet, physical activity, and individual metabolism. Track your progress with our free progress tracker.
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.