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 Food Delivery and Prescription Medication in the UK
Weight loss food delivery services can support your weight management goals, but combining them with prescription medication may offer additional benefit for eligible adults. The UK has several prescription-only weight loss medications available through NHS specialist services or private prescribing. This guide explains your options, how they work together, and whether you might be eligible for prescription support alongside dietary changes.
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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 Prescription Weight Loss Options and Eligibility
Three prescription-only weight management medications are currently licensed in the UK: Mounjaro (tirzepatide), Wegovy (semaglutide), and Saxenda (liraglutide). All work by mimicking natural hormones that regulate appetite and help you feel fuller after smaller meals. Eligibility typically requires a BMI of 30 or above, or 27 or above if you have weight-related health conditions such as type 2 diabetes, high blood pressure, or cardiovascular disease. Adults of South Asian, Chinese, Black African, or Black Caribbean heritage may have lower BMI thresholds. Clinical trials show these medications support weight loss alongside a reduced-calorie diet and increased physical activity — they work best when combined with lifestyle changes, including structured meal planning or food delivery services focused on balanced, portion-controlled nutrition.
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 Access vs Private Prescribing
In the UK, you can access prescription weight loss medication through two routes. NHS access is via referral to a tier 3 specialist weight management service, though waiting lists vary significantly by region and availability is patchy. Private prescribing is available through online consultations with UK-licensed prescribers, followed by dispensing through a registered pharmacy — no NHS referral required, though there is a cost. Before pursuing either route, speak with your GP about whether you're eligible, whether medication is appropriate for you personally, and how it fits with any food delivery or dietary plan you're already following. Your GP can also advise on NHS availability in your area and help you understand what weight management support is available to 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.
Can I use weight loss food delivery instead of prescription medication?
Yes — food delivery services focused on balanced, calorie-controlled meals are an excellent first-line approach and are available without prescription. However, if you have a BMI of 30 or above, or 27 or above with weight-related health conditions, prescription medication may be an option to discuss with your GP. Many people benefit from combining dietary support with medication.
How do prescription weight loss injections work?
Medications like Mounjaro and Wegovy are GLP-1 or GIP/GLP-1 receptor agonists that mimic natural hormones regulating appetite. They help reduce hunger, increase feelings of fullness, and slow digestion. Individual results vary, and they work best alongside a reduced-calorie diet and increased physical activity.
What's the difference between Mounjaro and Wegovy?
Mounjaro (tirzepatide) activates two hormone pathways (GIP and GLP-1), whilst Wegovy (semaglutide) activates one (GLP-1 only). Both are once-weekly injections. Clinical trials show Mounjaro may support slightly higher average weight loss, but individual results vary significantly. Both require a prescription and clinical assessment.
How do I check if I'm eligible for prescription weight loss medication?
Start by speaking with your GP about your weight and health. They can calculate your BMI and discuss eligibility based on your personal health profile. You can use our free BMI calculator on this page to understand where you sit, then bring that conversation to your GP.
Can I use our free weight loss calculator to estimate results if I start medication?
Yes — our GLP-1 weight loss calculator can help you project potential weight loss outcomes at different doses, based on clinical trial data. Remember that individual results vary, and any projection is an estimate. Always discuss realistic expectations with your prescriber or GP.
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.