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
Mounjaro and Diabetes — What UK Patients Need to Know
Mounjaro (tirzepatide) is a prescription-only injection that works differently for diabetes management compared to traditional insulin. In the UK, it's increasingly prescribed through NHS specialist services and private clinics for adults with type 2 diabetes who need better blood sugar control. This dual GIP and GLP-1 receptor agonist not only helps regulate glucose levels but may also support weight loss, which is important because many people with type 2 diabetes are overweight or obese. Understanding how Mounjaro fits into NHS diabetes care and what eligibility looks like can help you have an informed conversation with your GP about whether it might be suitable for you.
10,000+ calculations today · NHS-aligned thresholds · 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/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 Mounjaro Works for Type 2 Diabetes in the UK
Mounjaro is a dual GIP and GLP-1 receptor agonist — meaning it activates two natural hormone pathways involved in blood sugar regulation and appetite control. Unlike traditional diabetes medications, tirzepatide (the active ingredient in the Mounjaro KwikPen) helps your body use insulin more effectively and slows how quickly food leaves your stomach, which steadies blood sugar after meals.
In the UK, type 2 diabetes patients are typically offered Mounjaro when:
- Other medications haven't achieved adequate blood sugar control
- Weight management is also a priority (especially important as excess weight worsens diabetes)
- You have cardiovascular risk factors or existing heart disease
- You're referred to a specialist diabetes or weight management service
The NHS is increasingly recognising that GLP-1 medications like Mounjaro can benefit both blood sugar and weight — addressing two major risk factors simultaneously. NICE guidance supports their use in specialist tier 3 diabetes services, though availability varies by region.
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 Access, Eligibility, and the Private Route
NHS access: Type 2 diabetes patients can be referred to specialist tier 3 diabetes services by their GP, where Mounjaro may be considered if other treatments have not worked. Waiting times vary significantly by region, and some areas have limited availability.
Private access: You can also obtain Mounjaro privately through a UK-licensed prescriber via an online consultation, then collect from a GPhC-registered pharmacy. This route bypasses NHS waiting lists but requires payment.
Eligibility: For diabetes specifically, your GP or specialist will assess whether Mounjaro is appropriate based on your HbA1c (average blood sugar over 3 months), kidney function, and other medications. Use our free BMI calculator and GLP-1 weight loss calculator to understand your baseline metabolic health before your consultation.
Dose and expectations: Mounjaro starts at 2.5 mg once weekly, increasing gradually to a maximum of 15 mg. Clinical trials showed significant HbA1c reductions and modest weight loss alongside lifestyle changes. Your prescriber will adjust your dose based on blood sugar readings and side effects. Monitor your progress using our free progress tracker to log weight, blood sugar readings, and energy levels over time.
- 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 get Mounjaro on the NHS for type 2 diabetes?
Yes, Mounjaro can be prescribed through NHS specialist diabetes services (tier 3), but you'll need a GP referral and availability varies by region. Waiting lists can be several months in some areas. Private prescription is also available through UK-licensed online prescribers without an NHS referral, though this requires payment.
Does Mounjaro replace insulin?
Mounjaro is not insulin — it works by activating GLP-1 and GIP receptors to improve your body's own insulin use. Some patients can reduce or stop insulin, but this must be managed by your prescriber. Never adjust insulin independently when starting any new diabetes medication.
How much weight loss should I expect with Mounjaro for diabetes?
Weight loss varies significantly between individuals. Clinical trials showed an average loss of 15–21% of body weight alongside a reduced-calorie diet and increased activity. Some people lose more, others less. Calculate your personal projections using our GLP-1 weight loss calculator above.
What are the side effects of Mounjaro for diabetes?
Most common side effects are nausea, diarrhoea, vomiting, and constipation — usually mild and improve over time. Serious side effects (severe stomach pain, gallbladder problems, pancreatitis) are rare but require urgent medical attention. Always report new symptoms to your diabetes team.
How does Mounjaro compare to Wegovy for diabetes?
Both are GLP-1-related medications, but Mounjaro is a dual GIP+GLP-1 agonist while Wegovy is GLP-1 only. Mounjaro may offer better blood sugar control for diabetes patients. Your prescriber will recommend which is most suitable based on your individual health profile and HbA1c targets.
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.