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
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Swimming Weight Loss Plan — Exercise, Medication & NHS Support
Swimming is one of the most effective forms of exercise for sustainable weight loss — it's low-impact, builds muscle, and burns significant calories. However, for many adults in the UK, combining swimming with medical weight management support can deliver better results. This guide explains how swimming fits into a weight loss strategy, and how prescription weight loss medication may help eligible adults alongside regular exercise and dietary changes.
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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 Prescription Weight Loss Options — Who's Eligible?
If you're overweight or obese and swimming alone hasn't achieved your weight loss goals, UK-licensed prescription medications may help. Three prescription options are available:
- Mounjaro (tirzepatide) — dual GIP and GLP-1 injection, once weekly, maximum dose 15 mg. Clinical trials showed average weight loss of 15–21% body weight over 72 weeks.
- Wegovy (semaglutide) — GLP-1 injection, once weekly, maximum dose 2.4 mg. STEP trials showed average weight loss of approximately 15% body weight at 68 weeks.
- Saxenda (liraglutide) — GLP-1 injection, daily dose up to 3 mg. Approved for weight management in UK adults.
You may be eligible if you have a BMI of 30 or above, or BMI 27–29.9 with a weight-related health condition (type 2 diabetes, high blood pressure, high cholesterol, or sleep apnoea). For South Asian, Chinese, Black African, or Black Caribbean adults, eligibility thresholds are lower. All medications are prescription-only and require clinical assessment. Individual results vary significantly.
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 — How to Get Started
You have two routes to prescription weight loss medication in the UK. NHS access is through tier 3 specialist weight management services — ask your GP for a referral. Waiting times vary by region (ICB) and can be several months. Private access is through online GPhC-registered pharmacies following a licensed prescriber assessment — this is faster but costs approximately £130–£320 per month depending on dose.
Whichever route you choose, medications work best alongside swimming, regular activity, and healthy eating. They reduce appetite and help you feel fuller, making it easier to stick to a calorie deficit. Use our free GLP-1 weight loss calculator to explore potential results at different doses, and our free BMI calculator to track your progress as you lose weight through swimming and medical 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.
Can I use swimming as my only weight loss method without medication?
Yes — swimming burns 200–500 calories per hour depending on intensity and body weight, supporting gradual weight loss when combined with a healthy diet. However, for many adults, results plateau after 6–12 months. Prescription medication can help overcome this plateau, but it's always optional and should be discussed with your GP.
What's the difference between Mounjaro and Wegovy?
Both are once-weekly injections. Mounjaro is a dual GIP+GLP-1 agonist (maximum 15 mg) showing average 15–clinically studied weight loss in trials. Wegovy is a GLP-1-only agonist (maximum 2.4 mg) showing average clinically studied weight loss. Mounjaro's dual mechanism may offer slightly greater results on average, but individual responses vary. A prescriber assesses which suits you.
Will I lose weight immediately on prescription medication?
No — weight loss is gradual. Most people lose 1–2 kg per week with medication, alongside diet and exercise. Maximum results typically appear after 16–20 weeks of dose escalation. Swimming regularly during this time amplifies results. Nausea and reduced appetite are common early side effects, which usually improve over time.
What happens if I stop swimming but continue medication?
Medication will still support weight loss through reduced appetite and increased fullness, but you'll miss the cardiovascular and muscle-building benefits of swimming. Combined approaches — medication plus regular activity — typically deliver better long-term results and improved fitness.
How do I know if I'm eligible for NHS weight loss medication?
If your BMI is 30 or above (or 27–29.9 with a weight-related health condition), ask your GP for a referral to your local tier 3 weight management service. They'll assess you and discuss options. For faster assessment, private prescribing through an online pharmacy is also available if you're eligible.
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.