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 for Weight Loss — With Prescription Support in the UK
Swimming is one of the most effective forms of exercise for weight management, burning significant calories whilst being gentle on joints. However, for many UK adults, combining regular swimming with prescription weight management medication may offer better results. If you have a BMI of 30 or above, or 27 or above with weight-related health conditions, you may be eligible for GLP-1 weight loss medication on the NHS or through private prescription. This guide explores how swimming supports weight loss and what prescription options are available in the UK.
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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 Weight Loss Medications Available
Three prescription-only weight management medications are licensed in the UK for adults who meet eligibility criteria:
- Mounjaro (tirzepatide) — a dual GIP and GLP-1 receptor agonist administered once weekly. Clinical trials showed an average weight loss of 15–21% of body weight over 72 weeks alongside reduced-calorie diet and physical activity.
- Wegovy (semaglutide) — a GLP-1 receptor agonist injected once weekly. Clinical evidence from trials demonstrated an average weight loss of approximately 14.9% of body weight when combined with lifestyle changes.
- Saxenda (liraglutide) — a daily GLP-1 injection with average weight loss of around 5–10% in clinical studies.
All three are prescription-only medications requiring a clinical assessment before dispensing. They work by helping regulate appetite and supporting feelings of fullness, making dietary changes easier to sustain. Individual results vary significantly, and medication is most effective when combined with regular physical activity like swimming and a balanced reduced-calorie diet.
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
In the UK, you can access weight loss medication through two routes:
- NHS: Referral to a tier 3 specialist weight management service by your GP. Availability and waiting times vary significantly by region. NICE has approved tirzepatide (Mounjaro) for NHS use, though regional variation means access is not universal.
- Private: Online consultation with a UK-licensed prescriber followed by prescription dispensing by a GPhC-registered pharmacy. Available without NHS referral, typically within days.
Your GP can assess your BMI and health status to determine eligibility. Use our free BMI calculator to check your current BMI before your appointment. If you're interested in projecting potential weight loss results with medication, our GLP-1 weight loss calculator can provide estimates at different doses. Combining swimming with appropriate medication—if eligible—may help you achieve sustained weight management and improved fitness.
- 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 for weight loss?
Swimming burns 200–600 calories per hour depending on intensity, stroke, and body weight. Freestyle at moderate intensity typically burns around 400–500 calories in an hour for an average adult. Combined with a calorie deficit (created through diet or medication), regular swimming can significantly support weight loss goals.
Can I take weight loss medication whilst swimming regularly?
Yes. In fact, combining prescription weight loss medication with regular physical activity like swimming often produces better results than either alone. Your prescriber will assess your individual health before prescribing. Always inform them of your exercise routine. Some people find they have more energy for swimming once nausea side effects settle.
What is the NHS eligibility for weight loss medication in the UK?
You may be eligible if your BMI is 30 or above, or 27–29.9 if you have weight-related health conditions (type 2 diabetes, high blood pressure, cardiovascular disease, or sleep apnoea). For South Asian, Chinese, Black African, or Black Caribbean adults, lower BMI thresholds apply. Your GP can assess your eligibility.
How long does it take to see weight loss results with medication?
Clinical trials typically show measurable weight loss within 4–8 weeks on prescription medication, with continued progress over 12–24 weeks. However, individual responses vary. Most people experience gradual, steady weight loss rather than rapid results. Combining medication with swimming and healthy eating supports sustainable outcomes.
Is prescription weight loss medication safe for active people?
Yes, when prescribed appropriately following clinical assessment. Common side effects like nausea typically reduce over time as your body adjusts. Always discuss your fitness level and swimming frequency with your prescriber. They can monitor your progress and adjust doses if needed to support your exercise routine safely.
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.