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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Fat Legs Before And After Weight Loss: UK Prescription Options
Excess fat around the legs can be stubborn to shift, even with diet and exercise. If you're struggling with leg fat and other areas of excess weight, prescription weight management medication may help. In the UK, several licensed options are available through NHS specialist services or private prescribing, though eligibility depends on your BMI and health profile. This guide explains how prescription weight loss medication works and how to find out if you qualify.
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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 Prescription Weight Loss Options
Mounjaro (tirzepatide) and Wegovy (semaglutide) are the main prescription weight loss medications available in the UK. Both work by mimicking natural hormones that regulate appetite and help you feel fuller after smaller meals. In clinical trials, people using these medications alongside a reduced-calorie diet and increased physical activity lost an average of 15–21% of their body weight over one to two years — though individual results vary significantly.
A third option, Saxenda (liraglutide), is also available but requires daily injections rather than weekly doses. These are prescription-only medicines that require a clinical assessment before being prescribed. Weight loss typically begins within the first few weeks, and as overall body weight decreases, fat reduction from the legs and other areas becomes visible. However, genetics and metabolism mean fat loss from specific areas (like the legs) cannot be assured.
- Mounjaro: dual GIP and GLP-1 receptor agonist, once weekly injection, doses from 2.5mg to 15mg
- Wegovy: GLP-1 receptor agonist only, once weekly injection, doses from 0.25mg to 2.4mg
- Both require a reduced-calorie diet and increased physical activity for best results
Clinically BackedWeight Loss
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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 and Eligibility
In the UK, prescription weight loss medication is available through NHS specialist tier 3 weight management services or through private online prescribing. Access via the NHS requires a referral from your GP and an assessment by a specialist weight management team — waiting times vary significantly by region (ICB area). Private access is faster but involves a cost.
To be eligible, you typically need a BMI of 30 or above, or a BMI of 27–29.9 with weight-related health conditions such as type 2 diabetes, high blood pressure, or sleep apnoea. If you're of South Asian, Chinese, Black African, or Black Caribbean heritage, lower BMI thresholds may apply due to higher health risks at lower weights. The best first step is to speak with your GP, who can assess your suitability and discuss your options for weight loss medication in the NHS or private sector. You can also use our free BMI calculator above to check your personal BMI and understand where you fall on the weight scale.
- 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 prescription weight loss medication specifically target fat on my legs?
No. Weight loss medication works throughout the body, not in specific areas. Fat loss is determined by genetics, metabolism, and overall calorie deficit. As you lose weight generally, fat from the legs will reduce alongside fat from other body areas, but the rate and order of fat loss cannot be controlled.
How long before I see visible changes in leg fat with Mounjaro or Wegovy?
Most people begin to see weight loss within 4–8 weeks of starting medication, though this varies. Visible fat reduction in the legs typically takes 3–6 months or longer, depending on how much weight you need to lose overall and individual metabolism. Consistency with diet and exercise is essential.
What's the difference between Mounjaro and Wegovy for weight loss?
Mounjaro is a dual GIP and GLP-1 receptor agonist (likely slightly more effective in trials), whilst Wegovy is a GLP-1 agonist only. Mounjaro has a maximum dose of 15mg weekly; Wegovy's maximum is 2.4mg weekly. Both are once-weekly injections. In clinical trials, average weight loss was similar (around 15–21% body weight), but individual results vary significantly.
Am I eligible for weight loss medication on the NHS?
Eligibility typically requires a BMI of 30 or above, or 27–29.9 with weight-related health conditions. However, NHS availability varies by region and waiting lists can be long. Your GP can assess your eligibility and refer you to a specialist weight management service in your area. Private options may be faster but involve costs.
What happens to leg shape and tone after weight loss from medication?
Weight loss reveals underlying muscle and bone structure. Skin elasticity may take time to adjust, particularly if you've lost a significant amount of weight. Regular strength training and adequate protein intake can help maintain muscle tone. Loose skin is not dangerous, though some people consider cosmetic options after very large weight losses.
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.