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
Type 2 Injections — What UK Adults Need to Know
Type 2 injections refer to prescription-only medications that help manage weight and blood sugar in UK adults. These GLP-1 and GIP/GLP-1 receptor agonist medications are available through the NHS specialist weight management services or private prescribing. If you have type 2 diabetes, prediabetes, or excess weight alongside health conditions, your GP can discuss whether these injections may help. This UK health guide explains how they work, eligibility, and NHS access options.
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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.
How Type 2 Injections Work and UK Eligibility
Type 2 injections such as Mounjaro (tirzepatide) and Wegovy (semaglutide) are prescription-only medicines that activate natural hormone pathways to help regulate appetite and blood sugar. Both are licensed in the UK for weight management in adults, and semaglutide is also used for type 2 diabetes management under the brand name Ozempic.
UK adults may be eligible if they have a BMI of 30 or above, or a BMI of 27–29.9 with at least one weight-related health condition such as type 2 diabetes, prediabetes, high blood pressure, or heart disease. Lower BMI thresholds (starting at 27.5) apply to adults of South Asian, Chinese, Black African, or Black Caribbean heritage due to higher health risks at lower weights. Eligibility is assessed individually by a GP or specialist prescriber following a clinical review.
These injections are not insulin and work differently—they support your body's own regulatory systems rather than directly lowering blood sugar. Use our free BMI calculator above to check your personal BMI instantly and understand where you fall on NHS health thresholds.
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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 Access and What to Expect in the UK
In the UK, type 2 injections are available through two main pathways. NHS access is via specialist tier 3 or tier 4 weight management services, typically requiring a GP referral. Waiting times vary significantly by region—some areas have long waiting lists. Private access is available through GPhC-registered online prescribers following an online clinical assessment, without needing NHS referral.
These medications work best alongside a reduced-calorie diet and increased physical activity. Clinical trials show average weight loss of 15–21% body weight, though individual results vary significantly. Side effects may include nausea, diarrhoea, and constipation, typically improving over time. Your prescriber will discuss benefits, risks, and whether this treatment suits your health goals. Track your progress with our free progress tracker if you're managing weight and health alongside any treatment plan.
- 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.
Are type 2 injections the same as insulin?
No. Type 2 injections like Mounjaro and Wegovy are GLP-1 or GIP/GLP-1 receptor agonists that work by regulating appetite and blood sugar through natural hormone pathways. Insulin is a different hormone that directly replaces what the pancreas cannot produce. Injections for type 2 are prescription-only and work differently from insulin therapy.
How do I access type 2 injections through the NHS in the UK?
You'll need a referral from your GP to a specialist weight management service (tier 3 or 4). Your GP will assess whether you meet eligibility criteria based on BMI and health conditions. Availability and waiting times vary by region and NHS integrated care board. Private access is also available through GPhC-registered prescribers without NHS referral.
What is the difference between Mounjaro and Wegovy for type 2 management?
Mounjaro (tirzepatide) is a dual GIP and GLP-1 receptor agonist with a maximum dose of 15 mg weekly. Wegovy (semaglutide) is a GLP-1 agonist only with a maximum dose of 2.4 mg weekly. Both are licensed for weight management in the UK. Clinical trials show Mounjaro may achieve slightly higher average weight loss, though individual results vary. Your prescriber will recommend which is more suitable for you.
What side effects should I expect from type 2 injections?
Common side effects include nausea, diarrhoea, vomiting, constipation, and stomach pain—usually mild and temporary as your body adjusts. Less common effects include dizziness, headache, and fatigue. Serious side effects are rare but may include severe stomach pain (pancreatitis) or allergic reactions. Always report any concerning symptoms to your prescriber immediately.
Can I use the BMI calculator to check if I'm eligible for type 2 injections?
Yes. Our free BMI calculator shows whether your BMI falls in NHS overweight or obese ranges. However, BMI is only one eligibility factor—your prescriber will also assess any weight-related health conditions, medical history, and current medications. Use the calculator as a starting point, then discuss results with your GP for personalised eligibility advice.
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.