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 Swimming Help in Weight Loss?
Yes, swimming is an effective form of physical activity that can support weight loss when combined with a calorie-reduced diet. Swimming burns significant calories, improves cardiovascular fitness, and is gentle on joints, making it ideal for sustainable weight management. However, weight loss ultimately depends on creating a calorie deficit — exercise alone is rarely enough. If you're looking to lose weight in the UK, understanding all available options — including lifestyle changes and prescription medication if eligible — can help you achieve better results.
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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
For adults struggling with weight management in the UK, prescription medications may be available alongside diet and exercise. Three GLP-1 medications are currently licensed for weight loss in the UK:
- Mounjaro (tirzepatide) — a dual GIP/GLP-1 injection helping reduce appetite and food cravings
- Wegovy (semaglutide) — a once-weekly GLP-1 injection that may support weight loss alongside lifestyle changes
- Saxenda (liraglutide) — a daily GLP-1 injection
Eligibility typically requires a BMI of 30 kg/m² or above, or 27–29.9 kg/m² with weight-related health conditions like type 2 diabetes or high blood pressure. Clinical trials showed these medications may help participants lose an average of 15–21% of their body weight — though individual results vary significantly. Use 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.
Accessing Weight Loss Support in the UK
If you're interested in prescription weight loss medication, your first step is to speak with your GP, who can assess your eligibility and discuss whether medication is appropriate for you. NHS access is through specialist tier 3 weight management services — though waiting lists can be lengthy in some areas. Private options are also available through GPhC-registered online pharmacies following an online clinical assessment. Regardless of the route, prescription medications work best when combined with diet and exercise — swimming is an excellent complementary activity. Use our free BMI calculator to check your starting point and understand your eligibility for medication 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 many calories does swimming burn per hour?
Swimming typically burns 250–500 calories per hour depending on intensity, stroke type, and body weight. A faster, more vigorous swim burns more calories than leisurely swimming. Combined with a reduced-calorie diet, swimming can support steady weight loss of approximately 0.5–1 kg per week.
Can swimming alone lead to weight loss?
Swimming alone is unlikely to produce significant weight loss without dietary changes. Exercise creates only part of the calorie deficit needed — most weight loss comes from eating fewer calories than you burn. Swimming should be combined with healthy eating for best results.
Is swimming suitable for everyone trying to lose weight?
Swimming is generally excellent for weight loss because it's low-impact and safe on joints, making it suitable for most people, including those with arthritis or mobility issues. However, if you have health concerns, check with your GP before starting any new exercise programme.
What prescription weight loss options are available on the NHS in the UK?
The NHS offers GLP-1 medications (Mounjaro, Wegovy, Saxenda) through specialist weight management services for eligible adults. Eligibility is typically a BMI of 30 or above, or 27 or above with weight-related health conditions. Your GP can refer you to local services.
Should I use weight loss medication instead of exercising?
No. Prescription weight loss medications are designed to work alongside diet and exercise, not replace them. Swimming and other physical activity remain important for cardiovascular health, muscle tone, and long-term weight management success.
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.