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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Chia Seed Drinks for Weight Loss in the UK
Chia seed drinks are often promoted as a natural weight loss aid, and whilst they can be part of a healthy diet, the evidence for significant weight loss is limited. If you're looking for clinically proven support for weight management in the UK, prescription options like Mounjaro and Wegovy may be available. This guide explains how chia seeds compare to evidence-based weight loss medication, who is eligible in the UK, and how to find out if prescription support is right for you.
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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 Weight Management Medication Options
If you're exploring weight management in the UK, several prescription medications with proven clinical evidence are available. Unlike supplements, these medications have been rigorously tested and approved by UK regulators.
- Mounjaro (tirzepatide) — A dual GIP/GLP-1 receptor agonist injection. Clinical trials showed participants lost an average of 15–21% of their body weight over 72 weeks when combined with dietary changes and physical activity.
- Wegovy (semaglutide) — A GLP-1 receptor agonist injection. In the STEP-1 trial, participants achieved an average weight loss of approximately 15% body weight at the maximum dose.
- Saxenda (liraglutide) — A daily GLP-1 injection, also with clinical trial evidence for weight loss support.
All three are prescription weight loss medications available through NHS specialist services or private prescribing in the UK. Unlike dietary supplements, these medications work on appetite regulation and metabolic pathways proven to support weight loss alongside lifestyle changes.
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.
Eligibility and How to Access Weight Loss Support in the UK
To access prescription weight loss medication in the UK, you'll need to meet certain eligibility criteria. Adults with a BMI of 30 or above, or 27 or above with weight-related health conditions (such as type 2 diabetes, high blood pressure, or sleep apnoea), may be eligible.
On the NHS, you can ask your GP about referral to a specialist tier 3 weight management service, though waiting times vary significantly by region. Alternatively, private online prescribing is available — you complete a clinical assessment with a UK-licensed prescriber, who decides if medication is suitable for you. Use our free BMI calculator above to check your personal BMI, and our GLP-1 weight loss calculator to explore potential outcomes with prescription medication.
- 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.
Are chia seed drinks effective for weight loss?
Chia seeds are nutritious and may help with satiety due to their fibre content, supporting a healthy diet. However, evidence for significant weight loss from chia seed drinks alone is limited. Prescription medications like Mounjaro and Wegovy have much stronger clinical evidence when used alongside dietary changes.
What is the difference between Mounjaro and Wegovy?
Mounjaro (tirzepatide) is a dual GIP and GLP-1 receptor agonist, whilst Wegovy (semaglutide) is a GLP-1 agonist only. Both are once-weekly injections. Clinical trials suggest Mounjaro may produce slightly higher average weight loss, but individual results vary significantly.
Can I get weight loss medication on the NHS in the UK?
Yes. The NHS approves weight loss medications through specialist tier 3 weight management services. You'll need a GP referral, and eligibility depends on your BMI and health conditions. Waiting times vary by region (ICB). Private prescribing is also available without waiting lists.
How quickly can I expect weight loss with prescription medication?
Weight loss typically becomes noticeable within 4–8 weeks, with most weight loss occurring in the first 3–6 months. The NHS recommends aiming for 0.5–1 kg per week for sustainable results. Track your progress using our free progress tracker as you progress through treatment.
Do I need to change my diet if I take weight loss medication?
Yes. Prescription weight loss medications work best alongside a reduced-calorie diet and increased physical activity. They support appetite control, but dietary and lifestyle changes are essential for sustained weight loss and long-term health benefits.
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.