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
Does Lymecycline Cause Weight Loss?
Lymecycline is an antibiotic used to treat acne and other infections in the UK — not a weight loss medication. While some people report minor weight changes when taking antibiotics, lymecycline is not designed for weight management. If you're interested in evidence-based weight loss support, the UK has several prescription options available. This guide explains what lymecycline actually does and introduces NHS-approved alternatives for eligible adults seeking weight management help.
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.
UK-Licensed Weight Loss Medications
If you're looking for prescription weight loss medication in the UK, there are three licensed options approved specifically for weight management. These are very different from antibiotics like lymecycline and work through hormonal pathways that regulate appetite and fullness.
Mounjaro (tirzepatide) is a dual GIP and GLP-1 receptor agonist licensed by the MHRA. Clinical trials showed participants lost an average of 15–21% of body weight over 72 weeks alongside reduced-calorie diet and increased physical activity. Wegovy (semaglutide) is a GLP-1 injection licensed for weight management, with trial data showing approximately 15% average body weight loss. Saxenda (liraglutide) is a daily injection option also approved in the UK.
All three require a prescription and clinical assessment. Individual results vary significantly, and these medications are used alongside, not instead of, lifestyle changes. Try our free GLP-1 weight loss calculator to explore potential outcomes at different doses.
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 to Weight Loss Treatment
In the UK, weight management medication access comes through two routes. The NHS offers specialist tier 3 and tier 4 weight management services in many areas — your GP can refer you if eligible. However, waiting lists are often long, and availability varies by region and ICB. Private prescribing is available through GPhC-registered online pharmacies following an online clinical assessment, offering quicker access without NHS referral.
Eligibility for prescription weight loss treatment generally requires a BMI of 30 or above, or BMI 27–29.9 with weight-related health conditions like type 2 diabetes or high blood pressure. Calculate your personal BMI using our free BMI calculator to see where you fall. Discuss options with your GP — they can advise whether you're eligible and which route is best for you.
- 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.
Does lymecycline cause weight loss?
No. Lymecycline is an antibiotic used to treat acne and bacterial infections — it is not a weight loss medication. While some people may experience minor appetite changes with any medication, lymecycline is not prescribed or intended for weight management.
What are the actual UK-approved weight loss injections?
The three MHRA-licensed medications for weight management in the UK are Mounjaro (tirzepatide), Wegovy (semaglutide), and Saxenda (liraglutide). These are GLP-1 or dual GIP/GLP-1 receptor agonists — entirely different from antibiotics. All require a prescription and clinical assessment.
How much weight can I expect to lose with prescription weight loss medication?
Clinical trials show average weight loss of 15–21% of body weight depending on the medication and dose. However, individual results vary significantly. These medications work best alongside a reduced-calorie diet and increased physical activity — they are not standalone solutions.
How do I find out if I'm eligible for NHS weight loss treatment?
Generally, you need a BMI of 30 or above, or BMI 27–29.9 with weight-related health conditions. Speak to your GP, who can assess your eligibility and refer you to a specialist weight management service. Use our free BMI calculator to check your current BMI.
Can I access weight loss medication privately in the UK without NHS referral?
Yes. GPhC-registered online pharmacies offer prescription weight loss medications following an online clinical assessment with a UK-licensed prescriber. This route is faster than NHS but involves private costs. Always ensure you use a registered pharmacy and qualified prescriber.
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.