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
Best Carbs for Weight Loss — UK Medication Perspective
When it comes to weight loss, carbohydrate choice matters, but prescription medication can provide additional support for eligible UK adults. While managing carb intake through diet remains important, many people find that combining dietary changes with prescription weight management options offers better results. This guide covers carbohydrate choices for weight loss alongside UK-licensed medication options that may help you achieve your goals. Our GLP-1 weight loss calculator can help you explore how medication might support your journey alongside dietary changes.
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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 Weight Loss Medication Options
Three prescription-only medications are licensed in the UK for weight management: Mounjaro (tirzepatide), Wegovy (semaglutide), and Saxenda (liraglutide). These GLP-1 and GLP-1/GIP medications work alongside reduced-calorie diets to help regulate appetite and support weight loss. In clinical trials, patients on these medications lost an average of 14–21% of body weight over 12–18 months, though individual results vary significantly.
- Mounjaro: Once-weekly injection, dual GIP/GLP-1 agonist, doses from 2.5 mg to 15 mg
- Wegovy: Once-weekly GLP-1 injection, doses from 0.25 mg to 2.4 mg
- Saxenda: Daily GLP-1 injection, doses from 0.6 mg to 3 mg
Each medication requires a prescription and clinical assessment to determine eligibility. Prescription medications work most effectively when combined with healthy carbohydrate choices and increased physical activity.
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 vs Private Access in the UK
NHS access to prescription weight loss medication is through specialist tier 3 weight management services. Eligibility typically requires a BMI of 30 or above, or 27–29.9 with weight-related health conditions such as type 2 diabetes or high blood pressure. Waiting lists vary significantly by region. Private access is available through GPhC-registered online pharmacies following an online clinical assessment, without NHS referral. Your GP can advise whether you meet eligibility criteria and discuss which route is appropriate for you. Combine medication with a balanced, carb-conscious diet and regular physical activity for best results.
- 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 are the best carbs for weight loss?
Complex carbohydrates with high fibre content are generally best: oats, brown rice, sweet potatoes, lentils, beans, and wholemeal bread. These digest slowly, keeping you fuller longer. Simple sugars and refined carbs (white bread, pastries, sugary drinks) cause rapid blood sugar spikes and should be limited. Our weight converter and BMI calculator can help you track progress as you adjust your diet.
Can prescription weight loss medication help if I'm eating carbs?
Yes. Mounjaro and Wegovy help regulate appetite and reduce cravings, making it easier to make healthier food choices—including better carb selections. These medications don't require eliminating carbs; they support you in eating smaller portions and choosing more nutritious options. Results are best when combined with dietary changes.
How do I know if I'm eligible for prescription weight loss treatment in the UK?
You may be eligible if your BMI is 30 or above, or 27–29.9 with weight-related health conditions like diabetes, high blood pressure, or sleep apnoea. Contact your GP for an assessment, or explore private online clinics offering clinical evaluations. Eligibility is assessed on an individual basis.
What's the difference between NHS and private prescription weight loss in the UK?
NHS access is through specialist services (tier 3) with waiting lists and regional variation. Private access is faster via online prescribing services following clinical assessment, but involves a cost (typically £130–£320 per month depending on dose). Both routes require a valid prescription from a UK-licensed prescriber.
How quickly will I see weight loss results with prescription medication?
Clinical trials show an average of 0.5–1 kg loss per week in the first weeks, with cumulative weight loss of 14–21% over 12–18 months. Individual results vary significantly and depend on dosage, diet, and physical activity. Use our GLP-1 weight loss calculator to estimate potential outcomes at different doses based on your personal context.
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.