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
Weight Loss Injections Available On The NHS
Weight loss injections are prescription-only medications that can help eligible adults manage their weight more effectively. In the UK, several GLP-1 and GIP receptor agonist medications are licensed for weight management and available through both NHS specialist services and private prescribing. This guide explains what options are available, who may be eligible, and how to access them through your GP or a licensed prescriber.
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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 medications are currently licensed for weight management in the UK: Mounjaro (tirzepatide), Wegovy (semaglutide), and Saxenda (liraglutide). Mounjaro and Wegovy are once-weekly injections, whilst Saxenda is injected daily. All three are prescription-only medicines that require a clinical assessment before being prescribed.
You may be eligible for weight management medication if you have a BMI of 30 kg/m² 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 cardiovascular disease. If you're of South Asian, Chinese, Black African, or Black Caribbean heritage, lower BMI thresholds may apply (from 27.5 kg/m²). Use our free BMI calculator to check your personal BMI and understand where you stand against NHS guidelines.
Clinical trials show that weight loss injections, alongside a reduced-calorie diet and increased physical activity, may help adults lose an average of 15–21% of their body weight, though individual results vary significantly.
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 And Next Steps
The NHS pathway to weight loss injections goes through specialist tier 3 weight management services. Your GP can refer you to your local service, but waiting lists vary significantly by region and can be several months long. Private prescribing offers faster access through licensed UK prescribers and GPhC-registered pharmacies without requiring an NHS referral, though this involves a cost.
To find out if you're eligible and which access route suits you, speak to your GP as a first step. They can assess your health, discuss your weight loss goals, and explain whether prescription medication might be appropriate for you. Your GP can also clarify NHS waiting times in your area or discuss private options. Try our GLP-1 weight loss calculator to explore potential outcomes at different medication doses.
- 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 is the difference between Mounjaro and Wegovy for weight loss?
Both are prescription weight loss injections, but they work slightly differently. Mounjaro (tirzepatide) activates two hormone pathways (GIP and GLP-1), whilst Wegovy (semaglutide) activates GLP-1 only. Clinical trials suggest Mounjaro may support slightly higher average weight loss (around 20.9% at the maximum dose), though individual results vary. Both require a prescription and clinical assessment.
How long does it take to get weight loss injections on the NHS?
Waiting times for NHS specialist weight management services vary significantly by region. Some areas offer appointments within weeks, whilst others may have waiting lists of several months. Your GP can refer you and tell you the specific waiting time in your area. Private prescribing typically offers faster access if you're willing to pay for treatment.
Am I eligible for weight loss injections if my BMI is 28?
At a BMI of 28, you may be eligible if you have at least one weight-related health condition (such as type 2 diabetes, high blood pressure, or cardiovascular disease). If you're of South Asian, Chinese, Black African, or Black Caribbean heritage, you may be eligible from a BMI of 27.5. Your GP or a licensed prescriber can assess your individual circumstances and confirm eligibility.
Can I get weight loss injections privately if the NHS waiting list is too long?
Yes. Weight loss injections are available through private online prescribing in the UK. You'll need a clinical assessment from a UK-licensed prescriber, and if approved, the prescription is dispensed by a GPhC-registered pharmacy. Private costs typically range from £129–£320 per month depending on the medication and dose.
Will weight loss injections work without diet and exercise changes?
Weight loss injections are most effective when combined with a reduced-calorie diet and increased physical activity. Clinical trials show that medication works best alongside lifestyle changes. Your prescriber will discuss diet and exercise as essential parts of your weight management plan, not as optional extras.
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.