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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Weight Loss Injections News in the UK
Weight loss injections are prescription medications that help some adults manage their weight through appetite suppression and metabolic support. In the UK, GLP-1 medications like Wegovy and dual GIP/GLP-1 drugs like Mounjaro have become increasingly prominent in weight management uk discussions. These are licensed prescription-only medicines available through NHS specialist services or private online prescribing. They work alongside dietary changes and physical activity, not as standalone solutions. Recent NHS guidance has expanded access to these medications for eligible adults, marking a significant shift in how prescription weight loss uk is approached within the healthcare system.
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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.
How Weight Loss Injections Work
GLP-1 receptor agonist medications like Wegovy (semaglutide) activate natural hormone pathways that regulate appetite and blood sugar. They signal to your brain that you are fuller after smaller meals, reduce food cravings, and slow how quickly food leaves your stomach. Dual GIP/GLP-1 medications like Mounjaro (tirzepatide) activate two pathways simultaneously, offering a different mechanism that some evidence suggests may produce greater average weight loss.
Clinical trials showed meaningful results: Wegovy users lost approximately 15% of body weight on average, whilst Mounjaro participants lost 15–21% depending on dose. However, individual results vary significantly. These medications are most effective when combined with a reduced-calorie diet and increased physical activity. Use our free GLP-1 weight loss calculator above to explore estimated outcomes at different dose levels.
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.
Prescription Weight Loss UK — Access and Eligibility
NHS access: Weight loss medication through the NHS is available via tier 3 specialist weight management services. Your GP can refer you, though waiting lists vary considerably by region and some ICBs have limited availability. Private access: Available through online prescription services following a clinical assessment with a UK-licensed prescriber.
Eligibility criteria include a BMI of 30 or above, or 27 or above with weight-related health conditions (type 2 diabetes, hypertension, cardiovascular disease, sleep apnoea). For adults of South Asian, Chinese, Black African, or Black Caribbean heritage, lower thresholds may apply due to higher health risks at lower BMI levels. A prescriber will assess your individual suitability during consultation. Track your progress with our free progress tracker once treatment begins.
- 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 weight loss injections available on the NHS?
Yes, through specialist tier 3 weight management services. Your GP can refer you, but availability varies by region and waiting times can be lengthy. Private prescription is available immediately through online services following clinical assessment.
What's the difference between Wegovy and Mounjaro?
Wegovy (semaglutide) is a GLP-1 agonist; Mounjaro (tirzepatide) is a dual GIP/GLP-1 agonist. Clinical trials showed Mounjaro achieved slightly higher average weight loss (15–21% vs 15%), though results vary individually. Both are once-weekly injections and prescription-only.
How much weight can you lose with weight loss injections?
Clinical trials showed average weight loss of 15% body weight with Wegovy and 15–21% with Mounjaro over approximately one year. Individual results vary based on dose, adherence, diet, and exercise. These medications work best alongside lifestyle changes, not as standalone treatment.
Are weight loss injections safe?
Both Wegovy and Mounjaro are licensed medications with established safety profiles. Common side effects include nausea, diarrhoea, and constipation, usually mild and temporary. Serious side effects are rare but include severe stomach pain (possible pancreatitis). Always discuss risks with your prescriber beforehand.
Can I use weight loss injections without changing my diet?
No. These medications are most effective alongside a reduced-calorie diet and increased physical activity. The NHS and clinical trials show best results with combined lifestyle changes. Use the BMI calculator above to assess your starting point, then discuss a plan with your healthcare provider. ```
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.