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
L-Carnitine for Weight Loss in the UK
L-carnitine is a naturally occurring compound found in meat and dairy products, often marketed as a weight loss supplement. However, it is not a prescription weight loss medication available through the NHS. If you're interested in evidence-based weight management support, the UK does offer prescription options for eligible adults. This guide explains what l-carnitine is, how it differs from licensed weight loss treatments, and what prescription alternatives are available through the NHS and private healthcare in the UK.
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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 Prescription Weight Loss Options
If you're looking for clinically proven weight loss support, the UK offers three prescription-only medications specifically licensed for weight management: Mounjaro (tirzepatide), Wegovy (semaglutide), and Saxenda (liraglutide). These are not supplements—they are prescription medicines that work by regulating appetite through GLP-1 and GIP hormone pathways. Clinical trials have shown average weight loss of 15–21% of body weight over a year, with results varying by individual.
- Mounjaro: A dual GIP/GLP-1 receptor agonist, once-weekly injection, licensed for adults with BMI 30+ or 27+ with weight-related health conditions
- Wegovy: A GLP-1 receptor agonist, once-weekly injection, same eligibility criteria as Mounjaro
- Saxenda: A daily GLP-1 injection, approved for weight management in UK adults meeting eligibility criteria
All three are used alongside a reduced-calorie diet and increased physical activity. Individual results vary significantly. A prescriber will assess your suitability based on your personal health history and BMI.
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.
Accessing Weight Loss Support: NHS vs Private Routes
In the UK, you can access prescription weight loss medication through two routes: NHS specialist services or private prescribing. For NHS access, your GP can refer you to a tier 3 specialist weight management service, though waiting lists vary significantly by region. Private access is available through online consultations with UK-licensed prescribers, without an NHS referral—though there are costs involved. Before pursuing any weight loss treatment, use our free BMI calculator to check your starting point, and discuss your options with your GP. They can advise on eligibility, explain what to expect, and help you decide which route suits your circumstances.
- 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 l-carnitine an effective weight loss supplement?
L-carnitine is a naturally occurring amino acid, but scientific evidence for its weight loss effectiveness is limited and mixed. Some small studies suggest modest effects, but it is not a prescription medication and is not licensed for weight loss in the UK. For clinically proven weight loss support, prescription options like Mounjaro and Wegovy are more strongly evidence-based.
Can I get l-carnitine on the NHS?
No. L-carnitine is a supplement, not a prescription medicine, so it is not available on the NHS. If you're eligible for prescription weight loss medication (BMI 30+ or 27+ with weight-related conditions), your GP can refer you to specialist services where licensed options like Mounjaro or Wegovy may be prescribed.
What is the difference between l-carnitine and prescription weight loss injections?
L-carnitine is a supplement with limited weight loss evidence. Prescription weight loss injections like Mounjaro and Wegovy are licensed medicines with strong clinical trial data showing 15–21% average body weight loss. They require a prescription and clinical assessment, and work by regulating appetite hormones (GLP-1/GIP). Supplements and prescription medicines are very different products.
How do I know if I'm eligible for prescription weight loss medication in the UK?
You may be eligible if you have a BMI of 30 kg/m² or above, or 27–29.9 with a weight-related health condition (such as type 2 diabetes, high blood pressure, or sleep apnoea). Use our free BMI calculator to check your BMI, then speak to your GP about your options and whether a referral to specialist services is appropriate.
What should I do if I'm interested in weight loss support?
Start by calculating your BMI using our free BMI calculator on this page. Then arrange a conversation with your GP about weight management options available to you. They can assess your eligibility for prescription treatments, discuss the pros and cons, and either provide support through NHS tier services or discuss private options. Sustainable weight loss works best with professional guidance and lifestyle changes.
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.