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
Smoking Cigarettes and Weight Loss — What You Need to Know
Smoking is often mistakenly believed to aid weight loss, but the relationship between smoking and weight management is more complex than many people realise. Whilst nicotine can temporarily suppress appetite and increase metabolism slightly, smoking actually undermines sustainable weight loss and poses serious health risks. If you're considering weight management as part of improving your health, understanding how smoking affects your body is essential.
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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.
How Smoking Affects Your Weight and Metabolism
Nicotine does stimulate your central nervous system and can increase metabolic rate by approximately 4–10%, which explains why some smokers weigh less than non-smokers on average. However, this small metabolic boost comes with significant health costs. Smoking damages your cardiovascular system, reduces oxygen delivery to muscles, and impairs insulin regulation — all of which interfere with long-term weight management and fitness.
Smokers often consume more calories from alcohol, snacks, and sugary drinks, and quitting smoking frequently leads to improved appetite regulation rather than weight gain if dietary habits are managed well. More importantly, smoking dramatically increases the risk of type 2 diabetes, heart disease, cancer, and premature death — far outweighing any minor weight effect. If you're exploring weight management in the UK through proper channels like NHS support or prescription weight loss medication, quitting smoking should be a priority conversation with your GP.
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.
Weight Gain After Quitting Smoking — and How to Manage It
Many people gain 2–3 kg after stopping smoking, largely because appetite normalises and many rely on food as a replacement habit. This is temporary and manageable. Using the BMI calculator on this page, you can track whether any weight gain affects your health category. If you're concerned about weight changes after quitting, your GP can discuss options including lifestyle support or, if appropriate, prescription weight loss medication.
For sustainable weight loss in the UK, focus on reduced-calorie eating and increased physical activity — the same foundations that support any healthy weight management plan. The health benefits of quitting smoking vastly outweigh the temporary weight concern, and your cardiovascular fitness will improve within weeks, making exercise easier and more enjoyable.
- 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 smoking help you lose weight permanently?
No. Whilst nicotine temporarily increases metabolism by 4–10%, this effect is modest and comes with serious health risks including cardiovascular disease, cancer, and diabetes. Any weight benefit is far outweighed by smoking-related health damage. Sustainable weight loss comes from healthy eating and physical activity, not nicotine dependence.
Why do smokers often weigh less than non-smokers?
Nicotine slightly boosts metabolism and can suppress appetite. However, many smokers also have other health factors affecting weight. The weight difference is typically small, and smoking damages overall health far more than any weight effect. Quitting smoking with proper nutrition support leads to better long-term outcomes.
How much weight do people typically gain after quitting smoking?
Average weight gain is 2–3 kg in the months after quitting. This usually stabilises within a year. Gain can be minimised by maintaining regular physical activity and avoiding using food as a replacement habit. The health benefits of quitting far outweigh temporary weight changes.
Can I use weight loss medication if I smoke?
Prescription weight loss medications like GLP-1 injections are typically assessed on an individual basis by a prescriber. Smoking increases cardiovascular risk, so your GP will need to evaluate your overall health profile. Quitting smoking is generally recommended before starting any weight management programme, as it improves medication effectiveness and reduces health risks.
Should I quit smoking or focus on weight loss first?
Both are important, but quitting smoking should be the priority — the health risks of smoking outweigh weight concerns. You can address both simultaneously with NHS support. Your GP can refer you to smoking cessation services whilst also discussing weight management options if you have a BMI of 30 or above or weight-related health conditions.
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.