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 Products Available in the UK
Weight loss products in the UK range from prescription medications to over-the-counter supplements and structured weight management programmes. Understanding what's available, how they work, and what evidence supports them is essential for making informed choices about weight management. Whether you're exploring prescription injections, NHS-supported programmes, or dietary approaches, this guide covers the main options available to UK adults and how to access them through the NHS or private prescribing.
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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.
Prescription Weight Loss Injections
Prescription weight loss injections are among the most effective medical weight loss products available in the UK. The two main options are Mounjaro (tirzepatide) and Wegovy (semaglutide), both licensed for weight management in adults.
Mounjaro is a dual GIP and GLP-1 receptor agonist administered once weekly. Clinical trials showed an average weight loss of 15–21% of body weight at the maximum 15mg dose over 72 weeks, alongside reduced-calorie diet and increased physical activity. Wegovy is a GLP-1 receptor agonist also given once weekly, with clinical trials showing average weight loss of approximately 14.9% body weight at the 2.4mg maximum dose. Both are prescription-only medicines requiring clinical assessment before prescribing. Access in the UK is through NHS specialist weight management services or private online prescribing following an online consultation with a licensed prescriber. Individual results vary significantly, and these medications are most effective when combined with lifestyle changes.
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 Weight Management Pathways
The NHS provides structured weight loss support through its four-tier weight management pathway. Tier 1 includes self-help resources, digital tools, and community programmes. Tier 2 involves primary care-based behaviour change support, such as the NHS Weight Loss Plan. Tier 3 is specialist multidisciplinary weight management services where prescription medications like Mounjaro and Wegovy may be offered — though availability varies significantly by region and waiting lists can be lengthy. Tier 4 covers bariatric surgery for severe obesity. Eligibility for prescription weight loss medication typically requires a BMI of 30 or above, or 27–29.9 with weight-related health conditions. Your GP can refer you to tier 3 services and discuss which weight loss products may suit your individual circumstances.
- 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 are the most effective weight loss products available in the UK?
Prescription injections — Mounjaro and Wegovy — have the strongest evidence for weight loss. Mounjaro showed average weight loss of 15–21% in trials, while Wegovy showed approximately 14.9% at maximum dose. Both require prescription and clinical assessment. NHS weight management programmes, calorie-controlled diets, and structured exercise are also evidence-based approaches.
Can I get prescription weight loss products through the NHS?
Yes, Mounjaro and Wegovy are available through NHS specialist tier 3 weight management services. You need GP referral and must meet eligibility criteria: BMI 30+, or 27–29.9 with weight-related health conditions. Availability and waiting times vary significantly by region. Private prescribing is also available without NHS referral.
What's the difference between Mounjaro and Wegovy?
Both are once-weekly injections for weight management. Mounjaro is a dual GIP+GLP-1 agonist with maximum 15mg dose; Wegovy is GLP-1-only with maximum 2.4mg dose. Mounjaro showed slightly higher average weight loss (15–21% vs 14.9%) in trials, but both require prescription. Individual response varies — neither is assured to work for everyone.
Are there side effects with prescription weight loss injections?
Yes. Common side effects include nausea, diarrhoea, vomiting, and constipation — particularly during dose escalation. These often decrease over time. Serious side effects are rare but can include pancreatitis or gallbladder problems. Your prescriber will discuss all risks and monitor you for adverse effects during treatment.
How can I track my weight loss progress with these products?
Use our free progress tracker to log your weight weekly or monthly and visualise your progress over time. Combine tracking with our free BMI calculator to monitor changes in your BMI category as you lose weight. This helps you see how lifestyle changes and medication are working together. ``` --- ## CONTENT NOTES: **Semantic Keywords Naturally Woven:** - "weight management" (intro + Col H) - "NHS weight loss" (Col I heading + Col J) - "lose weight uk" (intro) - "glp-1 weight loss" (Col H) - "weight loss injections uk" (Col H) - "prescription weight loss" (Col H + Col K Q2) - "weight loss medication nhs" (Col K Q2) - "bmi weight loss" (Col K Q5) **Tool References:** - BMI calculator: naturally referenced in Col K Q5 for progress tracking - GLP-1 calculator: not forced here (not essential for this broad informational page) - Weight converter: not forced (not relevant to this topic) - Progress tracker: directly referenced in Col K Q5 as actionable tool for tracking weight loss journey **Compliance & CMKB Adherence:** ✅ UK English throughout (GP, NHS, stone, lbs, kg) ✅ Conditional language ("may", "showed", "individual results vary") ✅ Prescription-only status stated clearly for Mounjaro/Wegovy ✅ Clinical trial data from CMKB (SURMOUNT for Mounjaro, STEP for Wegovy) ✅ No pharmacy names mentioned ✅ No assured outcomes ✅ BMI context provided (eligibility criteria) ✅ Tier structure from NHS pathway included ✅ Acknowledges regional variation in NHS access ✅ Friendly, informative tone on weight topic **Structure:** - 65 words intro (plain text) - 179 words Col H (minified HTML, prescription injections detail) - 148 words Col J (minified HTML, NHS pathways practical info) - 5 FAQs with 40–80 word answers
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.