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 Herbs and Prescription Medication in the UK
Weight loss herbs are popular in health food shops and online, but evidence for their effectiveness is limited. If you're looking for clinically proven weight management support in the UK, prescription medications are available for eligible adults. This guide explains what herbs claim to do, why prescription options exist, and how to find out if you qualify for NHS weight loss support or private prescription medication.
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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 Options
If you're interested in medically supported weight management in the UK, three prescription medications are licensed for this purpose: Mounjaro (tirzepatide), Wegovy (semaglutide), and Saxenda (liraglutide). These are GLP-1 and GIP/GLP-1 receptor agonist medications that work differently to herbal supplements — they're injected medications that help regulate appetite and support feeling fuller after meals. Clinical trials show Mounjaro helps participants lose an average of 15–21% of body weight, while Wegovy supports an average loss of around 15%. Individual results vary significantly. These medications are prescription-only and require a clinical assessment to determine eligibility. You can access them through NHS specialist weight management services or private prescribing following an online consultation with a UK-licensed prescriber. Calculate your current BMI using our free BMI calculator above to see where you stand relative to NHS eligibility thresholds.
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 Eligibility and How to Get Started
In the UK, you may be eligible for prescription weight loss medication if you have a BMI of 30 or above, or a BMI of 27–29.9 with weight-related health conditions like type 2 diabetes, high blood pressure, or sleep apnoea. South Asian, Chinese, Black African, and Black Caribbean adults may have access to lower BMI thresholds due to higher health risks at similar weights. To explore your options, start by speaking with your GP about weight management support. Your GP can refer you to tier 3 specialist services for NHS medication access, though waiting lists vary by region. Alternatively, private online prescribing allows eligible adults to access prescription weight loss treatment without an NHS referral. Try our free GLP-1 weight loss calculator to understand potential outcomes, and use the weight converter on this page to track your current weight in metric and imperial measurements.
- 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.
Do weight loss herbs actually work?
Most weight loss herbs have limited scientific evidence. Some, like green tea extract, show modest effects in studies, but results are typically small compared to dietary changes or exercise. Herbal supplements are not regulated as strictly as medications, and quality varies widely. If you're seeking evidence-based weight management, prescription medication or lifestyle changes supported by an NHS programme may be more effective.
What's the difference between herbs and prescription weight loss medication?
Weight loss herbs are unregulated supplements with minimal clinical evidence. Prescription medications like Mounjaro and Wegovy are licensed by the MHRA, undergo rigorous clinical trials, and have proven effectiveness. Prescription medications require a clinical assessment and prescription from a licensed healthcare professional, whereas herbs can be bought without oversight.
Am I eligible for NHS weight loss medication?
You may be eligible if you have a BMI of 30 or above, or 27–29.9 with weight-related health conditions. Ethnicity-adjusted thresholds apply for South Asian, Chinese, Black African, and Black Caribbean adults. Speak with your GP to discuss eligibility and potential referral to specialist weight management services in your area.
Can I get prescription weight loss medication privately if I'm not eligible on the NHS?
Yes. Private prescription weight loss medication is available through UK-licensed online prescribers for eligible adults. A prescriber will assess your health and determine suitability. Private access bypasses NHS waiting lists but involves a cost, typically ranging from £129–£320 monthly depending on medication and dose.
Should I try herbs before seeing my GP about weight management?
If you're seeking weight management support, it's worth speaking with your GP first. Your GP can discuss your health, any underlying conditions, and which approaches — including prescription medication, NHS programmes, or lifestyle changes — might suit you best. This ensures you get evidence-based advice tailored to your individual situation.
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.