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 Smoking Help With Weight Loss?
Smoking does not help with weight loss in any meaningful or safe way. Whilst some people experience slight weight changes when smoking due to appetite suppression, the serious health risks far outweigh any temporary weight effects. If you're interested in sustainable weight management in the UK, prescription medications and lifestyle changes are far safer, more effective options backed by clinical evidence. This guide explores why smoking isn't a weight loss strategy and what actually works.
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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-Licensed Prescription Weight Management Options
If you're looking for evidence-based weight management in the UK, several prescription medications are available following clinical assessment. These offer real support for weight loss alongside lifestyle changes, unlike smoking which damages your health.
- Mounjaro (tirzepatide) — A dual GIP/GLP-1 receptor agonist. Clinical trials showed participants lost an average of 15–21% body weight over 72 weeks. Administered as a once-weekly injection with doses ranging from 2.5 mg to 15 mg.
- Wegovy (semaglutide) — A GLP-1 receptor agonist. STEP trial data showed average weight loss of approximately 15% body weight. Once-weekly injection with doses up to 2.4 mg.
- Saxenda (liraglutide) — A daily GLP-1 injection for weight management, with doses up to 3 mg per day.
All three are prescription-only medicines requiring assessment by a UK-licensed prescriber. You may be eligible if you have a BMI of 30 or above, or 27–29.9 with weight-related health conditions such as type 2 diabetes, high blood pressure, or sleep apnoea. Try our free GLP-1 weight loss calculator to explore potential outcomes with medication support.
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.
How to Access Weight Loss Support in the UK
Access to prescription weight management in the UK comes through two main routes. NHS access requires referral to specialist tier 3 weight management services through your GP, though waiting times and availability vary significantly across regions. Private access is available through online clinical assessments with UK-licensed prescribers, with no NHS referral needed.
The most effective approach combines medication with lifestyle changes: reduced-calorie diet, increased physical activity, and behaviour change support. Calculate your BMI using our free BMI calculator to understand your starting point, then discuss weight management options with your GP. They can advise on NHS eligibility or refer you to appropriate services. Individual results vary, and a prescriber will assess whether medication is suitable for your personal health 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.
Why do some smokers not gain weight when they quit?
Nicotine suppresses appetite temporarily and increases metabolism slightly, so quitting can lead to initial weight gain. However, this is temporary and manageable with healthy eating and activity. The long-term health benefits of quitting smoking far outweigh modest weight changes.
Is smoking ever recommended for weight management?
No. Smoking causes serious harm including lung disease, heart disease, and cancer. It's never medically recommended for weight loss. Safe, evidence-based alternatives like prescription medications and lifestyle changes are always preferable.
Can I use weight loss medication like Mounjaro while smoking?
Yes, but smoking whilst taking weight loss medication increases cardiovascular risk. Your prescriber will assess your overall health. Quitting smoking whilst using weight management support significantly improves health outcomes.
What's the best way to lose weight without smoking?
A combination approach works best: calorie deficit (approximately 500 kcal per day for 0.5 kg weekly loss), increased physical activity, and if eligible, prescription weight loss medication. Use our GLP-1 weight loss calculator to explore medication options and speak with your GP.
How long does it take to lose weight with prescription medication?
Individual results vary. Clinical trials typically show meaningful weight loss over 12–16 weeks, with continued loss over months. Results depend on dose, adherence, diet, and activity level. Your prescriber will monitor progress and adjust treatment accordingly.
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.