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
What is a Weight Loss Aid and How Can It Help?
A weight loss aid is any tool, medication, or intervention that supports you in achieving sustainable weight reduction. In the UK, weight loss aids range from prescription injections and medications to dietary approaches, exercise programmes, and digital support tools. The most effective weight loss aids combine multiple strategies — medication alongside lifestyle changes typically produces better results than either approach alone. Whether you're looking to lose weight through NHS weight management services or exploring private options, understanding what's available helps you make informed decisions about your health.
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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.
Types of Weight Loss Aids Available in the UK
Prescription weight loss medications are among the most effective weight loss aids currently available. In the UK, GLP-1 weight loss injections like Wegovy (semaglutide) and Mounjaro (tirzepatide) are licensed for adults with a BMI of 30 or above, or 27 or above with weight-related health conditions. These medications work by reducing appetite and helping you feel fuller after smaller meals. Clinical trials showed that Wegovy users lost an average of 15% of their body weight, though individual results vary significantly.
- Prescription injections: Once-weekly GLP-1 medications (Wegovy, Mounjaro, Saxenda)
- Lifestyle interventions: Structured diet and exercise programmes, often through NHS weight management services
- Digital tools: Calorie tracking apps, weight loss calculators, and progress monitoring platforms
- Behavioural support: Group programmes and one-to-one coaching
Access to weight loss medication NHS services is through specialist tier 3 weight management clinics, though availability varies by region. Private prescribing is also available following an online clinical assessment with a UK-licensed prescriber.
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.
How to Choose the Right Weight Loss Aid for You
The best weight loss aid depends on your personal circumstances, health profile, and preferences. Start by checking your BMI using our free BMI calculator — this helps determine whether you're eligible for prescription options. If your BMI falls in the overweight or obese range, your GP can refer you to NHS weight management services, which typically begin with lifestyle support before considering medication.
For prescription weight loss UK treatment, a clinical assessment is essential — prescribers evaluate your health history, current medications, and specific weight-related conditions. Even with medication, bmi weight loss success requires lifestyle changes: a reduced-calorie diet and regular physical activity. Track your progress using our free progress tracker to monitor your results over time.
- 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 safest weight loss aid?
The safest approach combines evidence-based methods: a modest calorie deficit (500 kcal/day), regular physical activity, and professional support. The NHS recommends losing 0.5–1 kg per week. If prescription medication is appropriate, it should always be combined with lifestyle changes, never as a replacement for them.
Can I get weight loss medication on the NHS?
Yes. If eligible (BMI ≥30 or BMI 27–29.9 with health conditions), you can be referred to a specialist NHS tier 3 weight management service by your GP. Availability varies significantly by region and waiting lists can be long in many areas. Private prescribing is available through licensed prescribers.
How effective is Wegovy as a weight loss aid?
In STEP clinical trials, Wegovy (semaglutide) helped participants lose an average of 15% of their body weight alongside dietary changes and exercise. Individual results vary — some people lose more, some less. It's a prescription-only medication requiring a clinical assessment before prescribing.
Are weight loss injections suitable for everyone?
No. Weight loss injections are prescription-only and not suitable for pregnant or breastfeeding women, people under 18, or those with certain medical conditions. A prescriber will assess your individual health profile to determine suitability. Always consult your GP or a licensed prescriber.
What lifestyle changes complement weight loss aids?
Effective lifestyle changes include: eating a balanced, calorie-controlled diet (ideally 500 kcal below maintenance), doing at least 150 minutes moderate exercise weekly, staying hydrated, getting adequate sleep, and managing stress. Use our GLP-1 weight loss calculator to project potential results and our progress tracker to maintain motivation.
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.