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 Weight Loss Injections — What You Need to Know
L carnitine weight loss injections are sometimes discussed as a weight management option, but they're not licensed or recommended by the NHS for weight loss in the UK. While L carnitine is a naturally occurring compound involved in fat metabolism, clinical evidence for injectable L carnitine as a standalone weight loss treatment is limited. If you're exploring weight management options, it's important to understand what evidence actually supports different approaches. Our free BMI calculator can help you assess your current weight status, and we'll explain what UK-approved weight management options actually offer based on clinical evidence.
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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.
L Carnitine vs. Licensed Weight Loss Injections
L carnitine is a compound naturally produced in the body that helps transport fatty acids into mitochondria for energy production. Injectable L carnitine supplements are marketed for weight loss, but they lack robust clinical evidence for this use in the UK. The NHS and NICE do not recommend L carnitine injections as a weight management treatment.
By contrast, GLP-1 weight loss injections like Wegovy (semaglutide) and Mounjaro (tirzepatide) are prescription-only medications licensed in the UK specifically for weight management. These have undergone rigorous clinical trials — the STEP trials showed semaglutide helped patients lose approximately 15% of body weight on average, alongside diet and exercise. Mounjaro demonstrated average weight loss of 15–21% across its SURMOUNT trials. Both are prescribed following clinical assessment and are supported by NHS guidance for eligible adults. Our GLP-1 weight loss calculator can help you explore potential outcomes with evidence-based medications.
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.
Getting Safe, Evidence-Based Weight Management in the UK
If you're interested in prescription weight loss support, the NHS recommends two main routes. First, speak to your GP about referral to a specialist weight management service — available free through the NHS, though waiting times vary by region. Second, private online prescribing services can assess you and issue a prescription for licensed weight loss medications like Wegovy or Mounjaro if clinically appropriate. Both routes require a clinical assessment; neither dispenses medication without prescription.
The most effective approach combines prescription medication (if eligible) with reduced-calorie diet and increased physical activity. Use our free weight converter to understand your current weight in different units, and our progress tracker to monitor changes over time as you work towards your health goals.
- 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 injection approved by the NHS for weight loss?
No. L carnitine injections are not licensed or recommended by the NHS for weight loss in the UK. While L carnitine plays a role in fat metabolism naturally, injectable supplements lack sufficient clinical evidence for weight management. The NHS recommends prescription medications like Wegovy or Mounjaro, which have undergone rigorous clinical trials and are specifically licensed for weight management.
How do GLP-1 weight loss injections differ from L carnitine?
GLP-1 medications (Wegovy/semaglutide, Mounjaro/tirzepatide) are licensed, prescription-only treatments with robust clinical trial data showing 15–21% average body weight loss. They work by activating hormone pathways that reduce appetite and support feeling fuller. L carnitine lacks this level of evidence. GLP-1 medications require clinical assessment and prescription; L carnitine supplements do not.
Can I get weight loss injections on the NHS in the UK?
Yes, but access is through specialist tier 3 weight management services. Your GP can refer you if you meet eligibility criteria (generally BMI ≥30, or BMI ≥27 with weight-related health conditions). Waiting times vary significantly by region. Private online prescribing services also offer licensed weight loss medications following clinical assessment, though these are not NHS-funded.
What does clinical evidence show about L carnitine and weight loss?
Clinical evidence for injectable L carnitine as a weight loss treatment is limited and inconsistent. Most studies are small, and results are modest at best. In contrast, GLP-1 medications have large, rigorous clinical trials (STEP and SURMOUNT trials) clearly demonstrating significant weight loss. Evidence-based weight management in the UK relies on these proven medications alongside lifestyle changes.
How do I know if I'm eligible for prescription weight loss treatment in the UK?
Generally, you may be eligible if you have a BMI of 30 kg/m² or above, or a BMI of 27–29.9 kg/m² with weight-related health conditions (diabetes, high blood pressure, sleep apnoea, etc.). Use our free BMI calculator to check your current BMI, then discuss eligibility with your GP or a private prescriber who can assess your individual circumstances.
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.