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
What's the Minimum Weight For Mounjaro in the UK?
Mounjaro (tirzepatide) is a prescription-only weight loss injection available in the UK, but there's no fixed minimum weight—eligibility is based on BMI and health conditions instead. Adults with a BMI of 30 or above, or BMI of 27–29.9 with weight-related health conditions like type 2 diabetes, high blood pressure, or sleep apnoea, may qualify. If you're a South Asian, Chinese, Black African, or Black Caribbean adult, lower thresholds may apply. Your GP or a licensed prescriber will assess your individual circumstances during a clinical consultation. Use our free BMI calculator above to check your personal BMI and see where you fall within the eligibility range.
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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.
Mounjaro Eligibility: BMI Thresholds and Health Conditions
Mounjaro eligibility in the UK is determined by BMI, not absolute weight. Since BMI combines weight and height, two people at the same weight may have different BMIs and eligibility status. The standard criteria are:
- BMI 30 or above: Obese category — generally eligible
- BMI 27–29.9 with a weight-related health condition: May qualify with evidence of type 2 diabetes, prediabetes, high blood pressure, abnormal cholesterol, sleep apnoea, or cardiovascular disease history
- Ethnicity adjustment: South Asian, Chinese, Black African, or Black Caribbean adults may qualify at BMI 27.5+ due to higher metabolic health risks at lower BMI levels
As a weekly weight loss injection, Mounjaro works through dose titration starting at 2.5 mg and escalating to a maximum of 15 mg. Access routes differ significantly: NHS specialist weight management services have lengthy waiting lists in many regions, while private prescription routes offer faster access following an online clinical assessment. Cost varies by dose and provider on the private route.
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 vs Private Access: Routes and Realistic Timelines
NHS access: Referral to a tier 3 specialist weight management service from your GP. NICE has approved tirzepatide (Mounjaro) for NHS use, but availability varies by region and waiting times can extend 6–18 months in many areas. Private access: Online consultation with a UK-licensed prescriber, typically same-week assessment and prescription. A GPhC-registered pharmacy dispenses the medication. Private costs range from approximately £129–£320 per month depending on dose. Both routes require a clinical assessment; neither provides medication without proper evaluation. Try our GLP-1 weight loss calculator to explore projected outcomes at different doses, and use the weight converter tool if you need to compare your weight across kg, stone, and pounds.
- 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 there a minimum weight in kilograms to get Mounjaro in the UK?
No specific minimum weight exists. Eligibility is based on BMI (combined weight and height calculation) rather than absolute weight. You need a BMI of 30 or above, or 27–29.9 with weight-related health conditions. Use our free BMI calculator to check your personal threshold instantly.
Can I get Mounjaro on the NHS if my BMI is between 27 and 30?
Potentially, yes—if you have at least one weight-related health condition such as type 2 diabetes, high blood pressure, abnormal cholesterol, obstructive sleep apnoea, or a history of heart disease or stroke. You'd need referral to a specialist tier 3 weight management service from your GP.
How quickly can I access Mounjaro privately?
Private access is typically faster than NHS. After an online clinical assessment with a UK-licensed prescriber, you may receive a prescription within days. The medication is then dispensed by a GPhC-registered pharmacy. Timescales depend on individual assessment and prescription processing.
What's the difference between Mounjaro and Wegovy for UK eligibility?
Both use the same BMI eligibility thresholds (30+, or 27–29.9 with comorbidities). The main differences are the mechanism of action—Mounjaro is a dual GIP and GLP-1 agonist, Wegovy is GLP-1 only—and maximum doses. Clinical trial data showed slightly higher average weight loss with Mounjaro, though individual results vary significantly.
Will a prescriber assess my health before issuing Mounjaro?
Yes, absolutely. Both NHS and private prescribers conduct a clinical assessment covering your medical history, current medications, and health conditions. You'll be asked about contraindications, family history, and suitability. This is a mandatory step—Mounjaro is prescription-only and requires professional clinical judgment before dispensing.
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.