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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How to Get Weight Loss Injections on the NHS
Weight loss injections are now available on the NHS for eligible adults in the UK, though access varies by region. The main prescription options are Mounjaro (tirzepatide), Wegovy (semaglutide), and Saxenda (liraglutide)—all approved medications that may support weight management alongside lifestyle changes. Getting these injections through the NHS typically requires a referral to a specialist weight management service and meeting specific BMI and health criteria. This guide explains the eligibility requirements, how the NHS pathway works, and what you need to do to start the conversation with your GP.
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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.
UK-Licensed Weight Loss Injections and Eligibility
Three prescription weight loss injections are currently licensed in the UK for weight management. Mounjaro (tirzepatide) is a once-weekly dual GIP and GLP-1 receptor agonist that may help reduce appetite and support feeling fuller after meals. Wegovy (semaglutide) is a once-weekly GLP-1 injection, also designed to help with appetite regulation. Saxenda (liraglutide) is a daily GLP-1 injection option.
To be eligible for prescription weight loss medication through the NHS, you typically need 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, high blood pressure, abnormal blood fats, sleep apnoea, or cardiovascular disease. If you are of South Asian, Chinese, Black African, or Black Caribbean heritage, lower BMI thresholds may apply—eligibility may start at BMI 27.5 or above due to higher health risks at lower weights.
Check your personal BMI using our free BMI calculator to see where you fall, then discuss your options with your GP.
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 Referral Pathway and Regional Variation
Accessing weight loss injections on the NHS is not a simple GP prescription—it requires referral to a specialist tier 3 or tier 4 weight management service in your area. Your GP assesses your eligibility and refers you to the service if appropriate. However, availability varies significantly by region. Some areas have dedicated weight management clinics with relatively short waiting times, whilst others have lengthy waiting lists or limited capacity.
To find out what's available in your area, ask your GP about the weight management pathway or contact your local Integrated Care Board (ICB). Be prepared that waiting times can be several months or longer in many regions. If you cannot wait or services are unavailable locally, private weight loss medication options are also available through UK-licensed prescribers following an online clinical assessment.
- 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.
What BMI do I need to qualify for weight loss injections on the NHS?
Generally, you need a BMI of 30 or above, or 27–29.9 with weight-related health conditions like type 2 diabetes or high blood pressure. If you're of South Asian, Chinese, Black African, or Black Caribbean descent, lower thresholds may apply (starting at BMI 27.5). Your GP can assess your individual eligibility.
How long does the NHS referral process take?
This varies by region. After your GP refers you to a specialist weight management service, waiting times can range from a few weeks to many months depending on local capacity. Contact your local Integrated Care Board to find out typical wait times in your area.
Can I get Mounjaro or Wegovy without going through the NHS?
Yes. Both Mounjaro and Wegovy are available privately through UK-licensed prescribers following an online clinical assessment. Private access bypasses NHS waiting lists but involves upfront costs, typically ranging from £130–£320 per month depending on dose and provider.
Will my GP automatically prescribe weight loss injections?
No. GPs typically refer suitable patients to specialist tier 3 or tier 4 weight management services rather than prescribing injections directly. The specialist service then assesses you and decides on treatment, which may include lifestyle support before medication is offered.
What happens during a weight management service appointment?
The specialist team assesses your health history, current weight, BMI, and any weight-related conditions. They discuss lifestyle changes, may recommend support programmes, and if eligible, explain medication options including benefits, side effects, and realistic expectations. They'll also discuss your commitment to combining medication with diet and physical activity changes.
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.