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
Acetyl L Carnitine and Weight Loss — What UK Residents Should Know
Acetyl L carnitine is a naturally occurring compound often marketed as a weight loss supplement. However, it is not a prescription medication and evidence for significant weight loss is limited. If you're interested in effective weight management in the UK, prescription options like Mounjaro and Wegovy are available for eligible adults. This guide explains both supplement approaches and evidence-based prescription alternatives approved by UK health authorities, so you can make an informed choice about what's right for 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-Approved Prescription Weight Loss Options
If you're considering weight management in the UK, several prescription-only medications are licensed specifically for weight loss. These include Mounjaro (tirzepatide), a dual GIP and GLP-1 receptor agonist; Wegovy (semaglutide), a GLP-1 agonist; and Saxenda (liraglutide), also a GLP-1 agonist taken daily. All three are approved by UK health authorities and work through different mechanisms to support appetite control and weight management. Clinical trials show these prescription options produce more substantial and consistent results than most supplements. Mounjaro users lost an average of 15–21% of body weight in trials, whilst Wegovy users saw approximately 14.9% average loss. Individual results vary, but prescription medications typically deliver measurable outcomes when combined with lifestyle changes.
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 Support
To access prescription weight loss medication in the UK, you need to meet specific eligibility criteria. Adults with a BMI of 30 or above, or BMI of 27–29.9 with weight-related health conditions such as type 2 diabetes, high blood pressure, or heart disease, may be eligible. You can check your BMI instantly using our free BMI calculator above. Eligibility is assessed on an individual basis by a healthcare professional. Access is available through NHS specialist weight management services (tier 3) or through private online prescribing following a clinical assessment. Contact your GP to discuss referral to NHS services, or explore private prescribing options if you wish to proceed more quickly.
- 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.
Is acetyl L carnitine approved as a weight loss medication in the UK?
No. Acetyl L carnitine is a dietary supplement, not a licensed weight loss medication. The UK medicines regulator (MHRA) has not approved it as a prescription weight management drug. Evidence for significant weight loss is limited compared to approved medications like Mounjaro and Wegovy.
What are the main prescription weight loss options available in the UK?
The three main UK-licensed prescription weight loss medications are Mounjaro (tirzepatide), Wegovy (semaglutide), and Saxenda (liraglutide). All are GLP-1 or GIP/GLP-1 receptor agonists requiring a prescription and clinical assessment. They are available through NHS specialist services or private prescribers.
How do I know if I'm eligible for prescription weight loss medication?
Eligibility typically requires a BMI of 30 or above, or 27–29.9 with weight-related health conditions. Use our free BMI calculator to check your BMI, then discuss options with your GP or a private prescriber who will assess your individual circumstances and medical history.
What weight loss results can I expect from prescription medications?
Results vary between individuals. Clinical trials show Mounjaro users lost 15–21% of body weight on average, whilst Wegovy users saw approximately 14.9%. These results were achieved alongside reduced-calorie diet and increased physical activity. Individual outcomes depend on adherence, lifestyle changes, and personal factors.
Can I get prescription weight loss medication through the NHS?
Yes. The NHS offers prescription weight loss medications through specialist tier 3 weight management services. Eligibility and availability vary by region. Ask your GP about referral to your local specialist weight management service, though waiting lists can be lengthy in some areas.
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.