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 With Avocado — UK Medication Options
Avocado is packed with healthy fats, fibre, and nutrients that support a balanced diet — but weight loss requires a broader approach. If you're looking to lose weight in the UK, you may have heard about prescription weight management options like Mounjaro and Wegovy. This guide explains how these medications work, who's eligible, and how to access them through the NHS or privately. Use our free BMI calculator above to check where you stand, then explore your options 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 Prescription Weight Loss Options
The UK has three prescription-only weight management medications licensed for adults with excess weight or weight-related health conditions:
- Mounjaro (tirzepatide) — a dual GIP and GLP-1 receptor agonist, once-weekly injection, starting at 2.5 mg up to 15 mg maximum. Clinical trials showed average weight loss of 15–21% of body weight alongside a reduced-calorie diet and increased physical activity.
- Wegovy (semaglutide) — a GLP-1 receptor agonist, once-weekly injection, doses from 0.25 mg to 2.4 mg. Clinical evidence suggests average weight loss around 14.9% of body weight.
- Saxenda (liraglutide) — a GLP-1 receptor agonist, once-daily injection, 0.6 mg to 3 mg daily. Typically produces more modest weight loss than Mounjaro or Wegovy.
Eligibility: You may qualify if you have a BMI of 30 or above, or a BMI of 27–29.9 with a weight-related health condition (type 2 diabetes, prediabetes, high blood pressure, sleep apnoea, or cardiovascular disease). For South Asian, Chinese, Black African, or Black Caribbean adults, lower BMI thresholds apply (BMI 27.5+). All medications are prescription-only and require a clinical assessment before dispensing.
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 — How to Get Started
Through the NHS: Ask your GP for a referral to your local tier 3 specialist weight management service. NHS access is available but varies significantly by region — some areas have waiting lists of several months. Your GP can advise on availability in your area and whether you meet local eligibility criteria.
Privately: Online prescribing services allow you to have a consultation with a UK-licensed prescriber without NHS referral. If approved, your prescription is dispensed by a GPhC-registered pharmacy. Private costs range from approximately £129–£320 monthly depending on medication and dose.
Next steps: Speak to your GP about which route is appropriate for you. Use our free GLP-1 weight loss calculator to explore potential outcomes at different doses, and track your progress with our free progress tracker once you begin any weight management 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.
Does eating avocado help with weight loss?
Avocado is nutrient-dense with healthy fats and fibre, which can support satiety and a balanced diet. However, it's calorie-dense (approximately 160 kcal per 100g), so portion control matters. Weight loss requires a calorie deficit — avocado alone won't create one. Combine it with other healthy foods and consider prescription options if needed.
Who is eligible for Mounjaro or Wegovy on the NHS?
Adults with a BMI of 30 or above, or 27–29.9 with weight-related health conditions like type 2 diabetes or high blood pressure, may be eligible. South Asian, Chinese, Black African, or Black Caribbean adults may qualify at lower BMI thresholds (27.5+). Your GP can assess your individual eligibility and refer you to specialist services.
What's the difference between Mounjaro and Wegovy?
Mounjaro is a dual GIP and GLP-1 agonist; Wegovy is GLP-1 only. Clinical trials suggest Mounjaro may produce slightly greater average weight loss (15–21% vs approximately 15% for Wegovy). Both are once-weekly injections. Individual results vary significantly. Your prescriber will recommend the most suitable option for you.
How quickly can I expect to lose weight with prescription medication?
The NHS recommends losing 0.5–1 kg (1–2 lbs) per week for sustainable results. Prescription weight medications work alongside reduced-calorie diet and increased physical activity — they're not replacements for lifestyle changes. Individual results vary. Our GLP-1 weight loss calculator can help you estimate potential outcomes at different doses.
Can I access prescription weight loss medication without seeing my GP?
Yes. Private online prescribing services allow consultation with a UK-licensed prescriber without NHS referral. If approved, a prescription is issued and dispensed by a GPhC-registered pharmacy. However, your GP can still offer valuable support and monitoring. Many people combine private prescription with NHS support from their 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.