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
Detox Weight Loss Smoothie Recipes and Prescription Support in the UK
Homemade smoothies can be a helpful part of a weight management routine, combining whole fruits, vegetables, and protein for balanced nutrition. However, if you're looking for additional support to lose weight in the UK, prescription weight management medications are now available for eligible adults through both NHS and private routes. This guide covers smoothie ideas alongside the medication options your GP can discuss with you.
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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
If you're pursuing weight management in the UK, three prescription-only medications are licensed for weight loss alongside lifestyle changes like healthier eating and exercise:
- Mounjaro (tirzepatide) — a once-weekly injection that activates dual GIP and GLP-1 hormone pathways. Clinical trials showed participants lost an average of 15–21% of body weight, though individual results vary significantly.
- Wegovy (semaglutide) — a once-weekly GLP-1 injection. Average weight loss in trials was around 15% of body weight when combined with reduced-calorie diet and physical activity.
- Saxenda (liraglutide) — a daily GLP-1 injection, offering another option for eligible adults.
All three are prescription-only and require assessment by a licensed prescriber before use. Your GP can advise whether any of these might be suitable for your individual circumstances.
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 Access vs Private Prescription Weight Loss in the UK
Through the NHS: Prescription weight loss medications are available via specialist tier 3 weight management services — typically requiring GP referral. Access varies significantly by region and waiting lists can be lengthy in many areas. Use our free BMI calculator above to check your starting point and share results with your GP when discussing referral options.
Privately: These medications are available through GPhC-registered online services following clinical assessment, without NHS referral. This offers faster access but involves private costs. Ask your GP whether prescription weight loss treatment might help you, or explore both NHS and private pathways to find what works best for your situation.
- 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.
Do detox smoothies replace the need for weight loss medication?
Detox smoothies can support a healthier diet and contribute to a calorie deficit, but they are not a substitute for prescription weight loss medication. If you have a BMI of 30 or above, or 27+ with weight-related health conditions, prescription options like Mounjaro and Wegovy may provide additional support alongside diet and exercise. Your GP can assess which approach is right for you.
Who is eligible for prescription weight loss medication in the UK?
Adults with a BMI of 30 kg/m² or above are generally eligible, or those with a BMI of 27–29.9 if they have weight-related conditions like type 2 diabetes, high blood pressure, or sleep apnoea. Eligibility varies by region and prescriber. Use the weight loss calculator on this page to explore potential outcomes, then speak with your GP about your specific eligibility.
Can I get Mounjaro or Wegovy on the NHS?
Yes — both are available through NHS specialist weight management services, though access varies by region and waiting lists can be significant. Your GP can refer you to your local tier 3 service if you meet eligibility criteria. Private prescription is also available through GPhC-registered providers for faster access, though this involves private costs.
What if I have a BMI in the overweight range but want to lose weight?
If your BMI is 25–29.9 (overweight), prescription medication may be available if you also have a weight-related health condition. Calculate your BMI using our free BMI calculator above, then discuss your health goals with your GP. Lifestyle changes including healthier smoothies, reduced-calorie diet, and physical activity are always appropriate starting points.
Are there side effects to weight loss injections?
Yes — common side effects include nausea, diarrhoea, constipation, and stomach discomfort, especially when starting or increasing doses. Most side effects improve over time. Serious side effects are rare but include severe stomach pain and allergic reactions. A prescriber will discuss all risks and benefits with you before prescribing.
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.