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
Non Prescription Weight Loss Supplements — What Works in the UK
If you're looking to lose weight without prescription medication, there are several evidence-based approaches available in the UK. While prescription weight loss injections like Mounjaro and Wegovy require a clinical assessment, many people successfully manage their weight through dietary changes, physical activity, and structured support programmes. This guide explains the non-prescription options available to you, how they work, and where to find reliable support through the NHS and other trusted sources.
10,000+ calculations today · NHS-aligned thresholds · 100% free
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.
Non-Prescription Weight Loss Options Available in the UK
The most effective non-prescription approach to weight management involves a combination of calorie deficit, increased physical activity, and behavioural support. The NHS recommends losing weight at a rate of 0.5 to 1 kg per week for sustainable results — this typically requires a calorie deficit of around 500 kcal per day.
- Dietary changes: Mediterranean diet, intermittent fasting (16:8 or 5:2), or low-carbohydrate approaches all show evidence for modest weight loss when combined with a calorie deficit
- Physical activity: Aim for at least 150 minutes of moderate activity per week, plus strength training twice weekly
- Behavioural support: NHS Weight Loss Plan (free online), local weight management groups, and apps can help sustain motivation
- Sleep and stress: Poor sleep and chronic stress increase appetite hormone levels — addressing these supports weight management
Use our free BMI calculator above to establish your starting point and healthy weight range for your height. Track your progress using our weight loss progress tracker throughout your journey.
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 Support and When to Consider Professional Help
The NHS provides free, evidence-based weight management support through a tiered pathway. Tier 1 includes self-help digital tools and community programmes. Tier 2 offers GP-led behaviour change support. Tier 3 provides specialist multidisciplinary weight management services, where prescription weight loss medication may be discussed if appropriate. Most people find success with non-prescription approaches first — your GP can advise you on local options and whether specialist referral would benefit you. If you have significant weight-related health conditions (type 2 diabetes, high blood pressure, sleep apnoea), professional support becomes increasingly valuable for achieving sustainable weight loss.
- 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's the difference between non-prescription and prescription weight loss approaches?
Non-prescription approaches rely on dietary changes, physical activity, and behavioural support to create a calorie deficit. Prescription weight loss medications (like GLP-1 injections) work alongside these lifestyle changes but require clinical assessment. Both can be effective — the choice depends on your individual circumstances and GP advice. Calculate your BMI first to understand your starting point.
Can supplements like green tea or garcinia help with weight loss?
Most over-the-counter weight loss supplements have limited evidence. Green tea shows modest effects (approximately 1–3 kg loss), and garcinia cambogia evidence is weak. None replaces the proven combination of calorie deficit and physical activity. Always discuss supplements with your GP before using them, especially if you take other medications.
How much weight can I realistically lose without medication?
With a 500 kcal daily deficit and increased activity, expect 0.5–1 kg per week. Even 5–clinically studied weight loss (achievable within 3–6 months) significantly improves health markers like blood pressure and blood sugar control. Use our GLP-1 weight loss calculator to explore how prescription options compare if you want to see alternative outcomes.
Is the NHS Weight Loss Plan actually free and effective?
Yes — the NHS Weight Loss Plan (available on the NHS website) is free and uses evidence-based behaviour change principles. It typically results in 5–8 kg loss over 12 weeks when followed consistently. Your GP can also refer you to local weight management services or digital programmes that are NHS-funded at no cost.
How long does non-prescription weight loss usually take compared to injections?
Non-prescription approaches typically take 3–6 months to see significant results, while GLP-1 injections (like Wegovy) may show faster early results in clinical trials — though individual outcomes vary considerably. The advantage of non-prescription approaches is they're sustainable long-term without ongoing costs or medication management.
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.