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
One Stone Weight Loss Before And After — What's Realistic?
Losing one stone (6.35 kg) is a significant and achievable weight loss goal for many UK adults. Whether through lifestyle changes alone or with prescription weight management support, one stone represents meaningful health improvements. This guide covers realistic expectations, UK-licensed medication options like Mounjaro and Wegovy, NHS weight loss pathways, and what eligible adults should know about prescription weight management options available in the UK today.
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 Medication Options
If you're looking at weight management in the UK, three prescription-only medications are currently licensed for weight loss support. Mounjaro (tirzepatide) and Wegovy (semaglutide) are once-weekly injections; Saxenda (liraglutide) is a daily injection. Clinical trials have shown these medications may help achieve average weight loss ranging from 15% to 21% of body weight when combined with a reduced-calorie diet and increased physical activity.
- Mounjaro: Dual GIP and GLP-1 agonist; doses 2.5 mg to 15 mg weekly; average loss ~15–21% body weight
- Wegovy: GLP-1 agonist; doses 0.25 mg to 2.4 mg weekly; average loss ~15% body weight
- Saxenda: GLP-1 agonist; daily injection; typically prescribed at 3 mg once daily
Individual results vary significantly. Eligibility requires a BMI of 30 or above, or 27 or above with weight-related health conditions such as type 2 diabetes, high blood pressure, or cardiovascular disease.
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 Versus Private Access in the UK
NHS access to weight loss medication is through specialist tier 3 or tier 4 weight management services, typically following GP referral. Availability and waiting times vary substantially by region and integrated care board (ICB). Many areas have significant waiting lists.
Private access is available through GPhC-registered online pharmacies following a clinical assessment with a UK-licensed prescriber, without requiring NHS referral. If you think you might be eligible, start by discussing your health with your GP, who can refer you to NHS services or advise whether private treatment might suit your circumstances. Your GP can also check for any medications or health conditions that might affect suitability.
Use our GLP-1 weight loss calculator to estimate potential weight loss at different medication doses, and our BMI calculator to check whether you fall within the eligibility range for prescription weight management support.
- 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.
How long does it take to lose one stone safely in the UK?
The NHS recommends losing 0.5–1 kg per week for sustainable results. One stone equals 6.35 kg, so safe weight loss would typically take 6–12 weeks. With prescription medication support alongside diet and exercise, results can be faster, but individual timescales vary. Always discuss realistic expectations with your healthcare provider.
Are Mounjaro and Wegovy available on the NHS?
Yes, NICE has approved tirzepatide (Mounjaro) and semaglutide (Wegovy) for NHS use through specialist weight management services. However, availability varies significantly by region, and referral through your GP to a tier 3 service is usually required. Private options are also available without NHS referral.
What results can I realistically expect from one stone weight loss?
Losing even one stone (6.35 kg) can meaningfully improve health markers including blood pressure, blood sugar control, cholesterol levels, and joint stress. Many people report improved energy, better sleep, and increased mobility. These benefits can occur at any weight, regardless of starting point.
What makes someone eligible for prescription weight loss medication in the UK?
UK eligibility typically requires a BMI of 30 or above, or BMI 27–29.9 with a weight-related health condition such as type 2 diabetes, high blood pressure, or cardiovascular disease. For South Asian, Chinese, Black African, or Black Caribbean adults, lower BMI thresholds may apply. Your GP or prescriber will assess your individual circumstances.
Can I use before-and-after photos to track one stone weight loss?
Yes, visual progress can be motivating. However, weight loss doesn't always show uniformly or immediately in photos. Use our free progress tracker to log your weight weekly alongside measurements and how you feel. This gives a fuller picture of progress beyond visual changes alone. ```
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.