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
Best Herbs for Weight Loss — and Prescription Alternatives in the UK
While certain herbs and supplements are marketed for weight loss, the most clinically proven options available in the UK are prescription weight management medications. If you're interested in weight management, it's worth understanding both herbal approaches and evidence-based prescription treatments that may be eligible for you. This guide covers what research shows about herbs and introduces the prescription weight loss options available through the NHS or private prescribing 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 Prescription Weight Loss Medications
For adults looking for robust clinical evidence, UK-licensed prescription weight loss medications offer significantly stronger support than herbal supplements. Three medicines are approved for weight management in the UK:
- Mounjaro (tirzepatide) — a once-weekly injection that activates two hormone pathways (GIP and GLP-1). Clinical trials showed average weight loss of 15–21% of body weight over 72 weeks, used alongside a reduced-calorie diet and increased physical activity.
- Wegovy (semaglutide) — a once-weekly GLP-1 injection with average weight loss around 15% of body weight in clinical trials.
- Saxenda (liraglutide) — a daily GLP-1 injection, typically resulting in modest weight loss for eligible adults.
All three are prescription-only medicines requiring a clinical assessment. Eligibility is based on BMI and weight-related health conditions. Use our free BMI calculator to check where you sit on the health weight scale, and our GLP-1 weight loss calculator can estimate 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.
NHS vs Private Access — How to Find Out if You're Eligible
In the UK, weight loss medication nhs access is through specialist tier 3 weight management services, usually requiring a GP referral. Waiting lists vary significantly by region. Alternatively, private weight loss medication is available through GPhC-registered online pharmacies following an online clinical assessment — no NHS referral required.
To find out if you're eligible for any weight loss treatment, speak to your GP about your health goals and any weight-related conditions (like type 2 diabetes, high blood pressure, or cardiovascular disease). Your GP can discuss prescription options or refer you to NHS specialist services. Track your weight loss progress using our free progress tracker once you begin any programme.
- 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 herbal weight loss supplements effective?
Some herbs (green tea, garcinia cambogia, conjugated linoleic acid) have modest research support, but effects are typically small. Prescription weight loss medications have far stronger clinical evidence. Always consult your GP before using supplements, especially if you're on other medications.
What's the difference between Mounjaro and Wegovy?
Mounjaro (tirzepatide) activates two hormone pathways and showed average weight loss of 15–21%. Wegovy (semaglutide) activates one pathway with average weight loss around 15%. Both are once-weekly injections. Individual results vary, and a prescriber will assess which is suitable for you.
Can I get weight loss medication on the NHS?
Yes, through specialist weight management services (tier 3). Your GP can refer you, though waiting lists vary by region and ICB. Private prescribing via online assessment is also available without an NHS referral for eligible adults.
Who is eligible for UK prescription weight loss medication?
Generally, adults with a BMI of 30 or above, or 27 or above with weight-related health conditions (type 2 diabetes, high blood pressure, cardiovascular disease, sleep apnoea). South Asian, Black African, Black Caribbean, and Chinese adults may have lower thresholds. Your GP can assess your individual eligibility.
How much weight will I lose on prescription weight loss medication?
Clinical trials show average weight loss of 15–21% of body weight, but individual results vary significantly. Weight loss depends on the specific medication, dose, adherence, diet changes, and physical activity. Use our GLP-1 weight loss calculator to estimate potential outcomes based on clinical trial data.
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.