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
Weight Loss Motivation: UK Medication & Support Options
Staying motivated during a weight management uk journey can be difficult, especially when trying to lose weight uk alone. If you've struggled with traditional diet and exercise approaches, prescription weight loss medication may be an option worth discussing with your GP. The NHS and private sector now offer evidence-based pharmaceutical support, including GLP-1 weight loss injections. Understanding what's available in the UK, who's eligible, and how these medications work can help you make informed decisions about your health and find the right approach for you.
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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 Prescription Weight Management Options
Three prescription medications are currently licensed for weight management in the UK: Mounjaro (tirzepatide), Wegovy (semaglutide), and Saxenda (liraglutide). Mounjaro and Wegovy are the most commonly prescribed for weight loss medication nhs and private use. Mounjaro works as a dual GIP and GLP-1 receptor agonist, whilst Wegovy is a GLP-1 agonist only.
- Mounjaro: Once-weekly injection, doses from 2.5 mg to 15 mg. Clinical trials showed an average weight loss of 15–21% body weight over 72 weeks alongside a reduced-calorie diet.
- Wegovy: Once-weekly injection, doses from 0.25 mg to 2.4 mg. Average weight loss around 15% of body weight in clinical trials.
- Saxenda: Daily injection, maximum dose 3 mg. Slightly lower average weight loss compared to Mounjaro and Wegovy.
Individual results vary significantly based on adherence, lifestyle changes, and personal metabolism. Our GLP-1 weight loss calculator can help estimate potential results at different doses. All three are prescription-only medicines requiring clinical assessment before being prescribed.
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
NHS route: Prescription weight loss uk through the NHS is available via specialist tier 3 weight management services. You'll need a GP referral, and access varies significantly by region and availability. Waiting lists can be lengthy in many areas. Your GP can assess your eligibility based on your BMI and any weight-related health conditions.
Private route: Available through GPhC-registered online pharmacies following a clinical assessment with a UK-licensed prescriber. No NHS referral needed; treatment is available more quickly. Costs typically range from £129–£320 monthly depending on dose.
Eligibility: Generally, adults with a BMI of 30 kg/m² or above, or 27–29.9 kg/m² with weight-related health conditions (type 2 diabetes, high blood pressure, sleep apnoea, cardiovascular disease) may be eligible. Use our free BMI calculator to check where you stand, then speak with your GP about prescription options.
- 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.
What's the difference between Mounjaro and Wegovy?
Mounjaro (tirzepatide) is a dual GIP and GLP-1 agonist, whilst Wegovy (semaglutide) activates GLP-1 only. Clinical trials suggest Mounjaro may produce slightly higher average weight loss (15–21% vs 15%), but individual results vary. Both are once-weekly injections. Your prescriber will recommend the most suitable option based on your health profile.
Can I get weight loss injections through the NHS?
Yes. Prescription weight loss through the NHS is available via specialist tier 3 weight management services with a GP referral. Access varies by region and waiting times can be long. If you're eligible, your GP can refer you. Private options are also available for faster access without an NHS referral.
How do I know if I'm eligible for prescription weight loss medication?
Eligibility is typically based on BMI 30 or above, or BMI 27–29.9 with weight-related health conditions like type 2 diabetes, high blood pressure, or sleep apnoea. Use our free BMI calculator to check your BMI, then discuss your eligibility with your GP or a licensed prescriber during a clinical assessment.
Will weight loss medication work without diet and exercise changes?
No. Prescription weight loss medications are most effective alongside a reduced-calorie diet and increased physical activity. Weight loss injections support appetite regulation and feeling fuller, but lifestyle changes are essential. Your GP or prescriber will discuss realistic expectations and the importance of behaviour change.
How can I stay motivated during weight loss treatment?
Set realistic goals, track your progress using tools like our free progress tracker, celebrate small wins, and stay connected with your GP or healthcare team for support. Many people find the physical effects of medication (reduced hunger) motivating. Remember that sustainable weight loss takes time — results typically appear over weeks and months, not days.
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.