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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Detox Smoothies and Weight Loss Medication in the UK
Detox smoothies can be a helpful part of a weight management plan, but for many people looking to lose weight in the UK, prescription medication options are also available. If you're interested in exploring all your options for sustainable weight loss, understanding what's available through the NHS and privately is important. This guide covers how smoothies fit into weight management, plus the prescription weight loss medications licensed in the UK and how to find out if you're eligible.
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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 Weight Loss Medications Available
For adults looking for prescription support alongside diet and lifestyle changes, three GLP-1 medications are licensed for weight management in the UK:
- Mounjaro (tirzepatide) — a dual GIP and GLP-1 receptor agonist that may help reduce appetite and support feeling fuller after meals. In clinical trials, participants on Mounjaro lost an average of 15–21% of their body weight over 72 weeks, though individual results vary significantly.
- Wegovy (semaglutide) — a GLP-1 receptor agonist that works similarly to Mounjaro but through a single mechanism. Clinical trials showed average weight loss of approximately 15% of body weight.
- Saxenda (liraglutide) — a daily GLP-1 injection, older than Mounjaro and Wegovy but still effective for eligible adults.
All three are prescription-only medicines. Eligibility typically requires a BMI of 30 or above, or 27 or above with weight-related health conditions such as type 2 diabetes, high blood pressure, or sleep apnoea. Individual results vary, and these medications work best when combined with reduced-calorie diet and increased physical activity — similar to the lifestyle approach that detox smoothies support.
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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 vs Private Access — How to Get Started
In the UK, prescription weight loss medication is available through two routes:
- NHS specialist services (Tier 3): Your GP can refer you to a specialist weight management service, where a clinical team will assess your eligibility and prescribe medication if appropriate. Availability varies significantly by region, and waiting lists can be lengthy in many areas.
- Private prescribing: UK-licensed prescribers offer online consultations followed by prescription if clinically suitable. This route doesn't require an NHS referral and is available without waiting lists, though there is a cost.
If you're considering weight loss medication alongside dietary changes like detox smoothies, start by discussing your options with your GP. They can assess whether medication is right for you and explain the NHS pathway in your area. You can also use our free GLP-1 weight loss calculator to estimate potential results at different doses, and our BMI calculator to check your current weight management category.
- 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 detox smoothies enough for weight loss, or do I need medication?
Detox smoothies can support weight loss as part of a reduced-calorie diet, but results vary widely between individuals. For some people, lifestyle changes alone work well. Others benefit from prescription medication alongside diet and exercise. This depends on your personal health, BMI, weight-related conditions, and how your body responds. Your GP can help you decide what approach suits you best. There's no one-size-fits-all answer — it's about finding what's sustainable for you.
What is a GLP-1 medication and how does it work?
GLP-1 medications like Wegovy and Mounjaro work by mimicking a natural gut hormone that signals fullness to the brain. They may help reduce appetite, decrease food cravings, and support feeling satisfied after smaller meals. They also slow how quickly food leaves your stomach. When combined with a reduced-calorie diet (like one featuring detox smoothies) and physical activity, clinical trials show they can support weight loss of 15–21% of body weight on average, though individual results vary significantly.
Am I eligible for prescription weight loss medication on the NHS?
You may be eligible if you have a BMI of 30 or above, or 27 or above with at least one weight-related health condition (such as type 2 diabetes, high blood pressure, or sleep apnoea). If you have South Asian, Chinese, Black African, or Black Caribbean heritage, lower BMI thresholds may apply. Your GP can assess your individual eligibility and, if appropriate, refer you to a specialist weight management service where medication can be prescribed.
How long does it take to see results with prescription weight loss medication?
In clinical trials, participants on Mounjaro and Wegovy saw gradual weight loss over 12–24 weeks as doses were increased, with continued loss over 68–72 weeks. However, individual timelines vary. Some people notice reduced appetite within days, whilst others take weeks to respond. Weight loss medication works best alongside a reduced-calorie diet and physical activity — consistency matters more than speed. Your prescriber will monitor your progress and adjust your treatment if needed.
Can I use detox smoothies with prescription weight loss medication?
Yes. In fact, homemade smoothies made from whole fruits, vegetables, and protein can fit well into a reduced-calorie diet alongside prescription weight loss medication. The key is ensuring smoothies are balanced (including protein and fibre) and portion-controlled. Avoid high-sugar shop-bought smoothies or "detox" blends with added sugars. When starting prescription medication, discuss your diet plan with your prescriber or a registered dietitian to ensure everything works together safely and effectively.
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.