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 Protein Bar For Weight Loss — And When Medication Might Help
Protein bars can be a convenient, high-protein snack that supports weight loss efforts by helping you feel fuller for longer. However, if you're looking to lose weight in the UK, you may also want to know about prescription weight management options available to eligible adults. This guide covers how protein bars fit into a weight loss plan, plus information about NHS-licensed weight loss medication like Mounjaro and Wegovy that can provide additional support alongside lifestyle changes.
10,000+ calculations today · NHS-aligned thresholds · 100% free
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.
Prescription Weight Loss Options Available in the UK
If you have a BMI of 30 or above, or a BMI of 27–29.9 with weight-related health conditions such as type 2 diabetes, high blood pressure, or sleep apnoea, you may be eligible for prescription weight loss medication on the NHS or privately.
Three main options are licensed in the UK:
- Mounjaro (tirzepatide) — A once-weekly injection that works on two hormone pathways to reduce appetite. Clinical trials showed participants lost an average of 15–21% of their body weight.
- Wegovy (semaglutide) — A once-weekly GLP-1 injection. Average weight loss in trials was around 15% of body weight.
- Saxenda (liraglutide) — A daily injection, also a GLP-1 medication.
All three are prescription-only and require a clinical assessment. They work best when combined with a reduced-calorie diet and increased physical activity — similar to how protein bars work best as part of an overall weight management UK approach, not as a standalone solution. Individual results vary significantly.
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 Options — And How to Find Out If You're Eligible
You can access prescription weight loss medication through two routes in the UK:
- NHS: Refer to your GP, who can assess you and refer to a specialist tier 3 weight management service. Availability varies by region, and waiting lists can be long in some areas.
- Private: Prescribers at registered pharmacies offer online consultations and can issue prescriptions if clinically appropriate, without NHS referral.
Whether you choose protein bars, medication, or a combination of both, calculate your BMI using our free BMI calculator above to see where you stand. This gives your GP a clear starting point for discussing weight management options. Your weight loss journey is personal — your GP can help determine whether prescription medication is right for you alongside dietary changes.
- 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 protein bars actually good for weight loss?
Protein bars can help if they're low in sugar and calories, as protein supports satiety and helps maintain muscle during weight loss. However, they're best used as part of an overall calorie deficit, not as a replacement for whole foods. A reduced-calorie diet is the foundation of any weight loss plan.
Who is eligible for prescription weight loss medication in the UK?
Adults with a BMI of 30 or above, or 27–29.9 with weight-related health conditions (type 2 diabetes, high blood pressure, sleep apnoea, etc.) may be eligible. Your GP can assess whether Mounjaro, Wegovy, or another option is appropriate for you.
How much weight can you lose with Mounjaro or Wegovy?
Clinical trials showed average weight loss of 15–21% of body weight with Mounjaro and around 15% with Wegovy. However, individual results vary significantly depending on adherence, diet, activity, and personal metabolism. Results are best when combined with a reduced-calorie diet and exercise.
Can I get Mounjaro or Wegovy on the NHS?
Yes, both are available through NHS specialist tier 3 weight management services following GP referral. However, availability varies by region and waiting lists can be substantial. Private options are also available through registered pharmacies following an online consultation.
Can I use both protein bars and weight loss medication together?
Yes. Prescription weight loss medications like Mounjaro work alongside dietary changes — which is where protein bars can fit as part of a balanced, reduced-calorie diet. Your prescriber will give you specific guidance on nutrition. Our GLP-1 weight loss calculator can help you estimate potential results.
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.