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 Sweets and Prescription Medication in the UK
If you're looking for weight loss sweets or appetite-suppressing products, it's worth knowing that prescription weight loss medication offers clinically proven alternatives available in the UK. For adults with a BMI of 30 or above, or 27 or above with weight-related health conditions, several prescription options are available through the NHS or private prescribers. These medications work differently than sweets or supplements — they're backed by clinical evidence and require a medical assessment. This guide explains your options and how to find out if you're eligible for weight management medication in the UK.
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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 Medications
Three main prescription medications are currently licensed in the UK for weight management:
- Mounjaro (tirzepatide) — a dual GIP and GLP-1 receptor agonist given as a once-weekly injection. Clinical trials showed an average weight loss of 15–21% of body weight over 72 weeks, though individual results vary.
- Wegovy (semaglutide) — a GLP-1 receptor agonist also given once weekly. In clinical trials, it helped participants lose approximately 15% of their body weight alongside lifestyle changes.
- Saxenda (liraglutide) — a daily GLP-1 injection, effective but requiring once-daily administration rather than weekly.
All three are prescription-only medicines and require a clinical assessment before being prescribed. They work by regulating appetite hormones and helping you feel fuller after smaller meals. Unlike weight loss sweets or supplements, these medications have robust clinical evidence supporting their effectiveness for weight management in UK adults.
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.
Eligibility and How to Access Weight Loss Treatment in the UK
You may be eligible for prescription weight loss medication if you have a BMI of 30 kg/m² or above, or 27–29.9 with a weight-related health condition such as type 2 diabetes, high blood pressure, or cardiovascular disease. To check your BMI, use our free BMI calculator above — it takes seconds and gives you a personalised starting point.
NHS access is through specialist tier 3 weight management services (your GP can refer you), though waiting lists vary by region. Private access is available through GPhC-registered online prescribers following a consultation, typically without NHS referral. Either route requires a licensed prescriber to assess whether medication is suitable for your individual health. Speak to your GP to discuss which option is right for 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.
Are weight loss sweets effective compared to prescription medication?
Most commercial weight loss sweets lack clinical evidence. Prescription medications like Mounjaro and Wegovy have been tested in large clinical trials and shown significant average weight loss (15–21% body weight). However, individual results vary. Sweets may help with cravings as part of a wider strategy, but prescription medication provides medically proven support.
How do I know if I'm eligible for weight loss medication in the UK?
Use our free BMI calculator above to check your BMI. If it's 30 or above, or 27–29.9 with conditions like diabetes or high blood pressure, you may be eligible. Speak to your GP or visit a private prescriber for a formal assessment — they'll review your health history and determine if medication is appropriate.
Can I get weight loss medication through the NHS?
Yes. Your GP can refer you to a specialist NHS weight management service (tier 3), where a team can assess you and prescribe medication if suitable. Waiting times vary by region and NHS availability. Private online prescribers also offer access without NHS referral — both routes require a prescription from a licensed UK prescriber.
What's the difference between Mounjaro and Wegovy for weight loss?
Mounjaro (tirzepatide) is a dual GIP/GLP-1 agonist and showed average weight loss of 15–21% in trials. Wegovy (semaglutide) is a GLP-1 agonist with average loss around 15%. Both are once-weekly injections. Mounjaro may produce slightly greater weight loss on average, but individual responses vary significantly. Your prescriber will recommend which is more suitable for you.
Do weight loss medications work without diet and exercise changes?
No. Prescription weight loss medications are most effective alongside a reduced-calorie diet and increased physical activity. They help control appetite and support feeling fuller, making it easier to maintain lifestyle changes — but they're not a substitute for them. Our progress tracker can help you log both medication use and lifestyle changes together.
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.