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 and BMI 27: NHS Eligibility and Guidance
If you have a BMI of 27, you may be eligible for Mounjaro (tirzepatide) on the NHS or through private prescription, depending on your individual health circumstances. A BMI of 27 falls in the overweight category according to NHS guidelines, though eligibility for prescription weight loss medications depends on additional health factors, not BMI alone. This guide explains NHS eligibility criteria, how BMI is assessed, and what weight management options are available through the NHS. Use our free BMI calculator above to check your personal BMI and understand where you fall on the NHS health spectrum.
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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 BMI Categories and Eligibility for Mounjaro
According to NHS guidelines, a BMI of 27 falls in the overweight category (BMI 25–29.9). However, eligibility for Mounjaro is not based on BMI alone. The NHS states that adults with a BMI between 27 and 29.9 may be considered for prescription weight loss medication if they also have at least one weight-related health condition, such as:
- Type 2 diabetes or prediabetes
- High blood pressure (hypertension)
- Abnormal blood fats (dyslipidaemia)
- Obstructive sleep apnoea
- History of cardiovascular disease, heart attack, or stroke
If you're of South Asian, Chinese, Black African, or Black Caribbean descent, the NHS applies lower BMI thresholds due to higher health risks at the same BMI. For these groups, eligibility may begin at BMI 27.5 or above, even without additional health conditions. Our free weight converter and BMI calculator can help you understand your individual measurements and where you sit within NHS categories.
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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 Weight Management Pathway and How to Access Support
The NHS offers a four-tier weight management pathway. At BMI 27 with health conditions, you would typically progress through tier 1 (self-help and digital tools), then tier 2 (primary care advice), before potentially being referred to tier 3 specialist weight management services where Mounjaro may be prescribed. Access varies significantly by region and depends on local NHS commissioning. Your GP can assess whether you meet criteria and refer you to specialist services if appropriate. In the meantime, use our free progress tracker to monitor your health metrics, and discuss your individual circumstances with your GP, who can advise on whether prescription weight loss treatment is suitable for you.
- 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 a BMI of 27 considered overweight according to the NHS?
Yes. A BMI of 27 falls within the NHS overweight category (25–29.9). However, this is not the same as obese. Eligibility for medications like Mounjaro at BMI 27 requires at least one additional weight-related health condition such as type 2 diabetes, high blood pressure, or cardiovascular disease. Your GP can assess your individual situation.
Can I get Mounjaro on the NHS with a BMI of 27?
Potentially, but not automatically. NHS criteria state that adults with BMI 27–29.9 may be prescribed weight loss medication if they have a weight-related health condition. You would need referral to a tier 3 specialist weight management service. Access varies by region, and waiting lists can be significant. Your GP can advise on local availability.
What if I'm of South Asian or Black African heritage with BMI 27?
The NHS applies lower BMI thresholds for people of South Asian, Chinese, Black African, or Black Caribbean descent due to higher cardiovascular and diabetes risk at the same BMI. You may be eligible for weight loss treatment at BMI 27.5 without requiring an additional health condition. Speak to your GP about whether you qualify.
What are the alternatives to Mounjaro if I don't meet NHS criteria?
The NHS first recommends lifestyle changes (diet and physical activity), tier 2 primary care programmes, and digital tools. If weight loss medication is appropriate, Wegovy (semaglutide) and Saxenda (liraglutide) are also licensed alternatives. Private online prescribing is also available outside the NHS if you meet clinical criteria.
How do I know if I have a weight-related health condition?
Common weight-related health conditions include type 2 diabetes, prediabetes, high blood pressure, high cholesterol, sleep apnoea, and cardiovascular disease. Your GP can check your blood pressure, blood sugar, and cholesterol levels during a health check. Many people are unaware they have these conditions, so requesting screening is worthwhile if considering weight loss medication.
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.