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
Actimel and Weight Loss: What You Need to Know
Actimel is a probiotic yogurt drink marketed for digestive and immune health, but it's not a weight loss medication. If you're looking for evidence-based weight management support in the UK, prescription medications like Mounjaro and Wegovy are available through NHS specialist services or private prescribing. These GLP-1 and dual GIP/GLP-1 receptor agonist injections have clinical trial evidence supporting weight loss alongside lifestyle changes. Our GLP-1 weight loss calculator can help you explore potential outcomes if you're eligible.
10,000+ calculations today · NHS-aligned thresholds · 100% free
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 weight management support, several prescription weight loss medications are licensed in the UK and available through NHS weight management services or private prescribing. Mounjaro (tirzepatide) is a once-weekly injection that activates both GIP and GLP-1 hormone pathways; clinical trials showed participants lost an average of 15–21% of their body weight. Wegovy (semaglutide) is another once-weekly GLP-1 injection, with trial evidence showing approximately 15% average weight loss. Saxenda (liraglutide) is a daily GLP-1 injection also licensed for weight management in UK adults.
These medications work best alongside a reduced-calorie diet and increased physical activity. Individual results vary significantly, and a prescriber will assess your eligibility based on your BMI and health history. Use our free BMI calculator to check where you stand, and our GLP-1 weight loss calculator can help estimate potential outcomes at different medication 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.
Eligibility and How to Access Weight Loss Support
To access prescription weight loss medication in the UK, you typically need 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. Your GP can refer you to a specialist tier 3 weight management service on the NHS, though waiting lists vary by region. Alternatively, prescription weight loss medication is available through private online prescribing with a UK-licensed prescriber—this route often has faster access without NHS referral.
Start by speaking to your GP about your weight management goals. They can assess your individual situation, discuss available options, and help you understand whether prescription support is appropriate for you. Track your progress with our free progress tracker once you've started any weight management 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.
Is Actimel scientifically proven to help with weight loss?
No. While Actimel contains probiotics that may support digestive health, there is no clinical evidence that it causes weight loss. It's a yogurt drink, not a weight loss medication. If you're seeking evidence-based weight management, prescription GLP-1 medications or lifestyle changes are more effective options.
What's the difference between prescription weight loss injections and supplements like Actimel?
Actimel is a food product marketed for general digestive health. Prescription weight loss injections like Mounjaro and Wegovy are pharmaceutical medications approved specifically for weight management, with clinical trial evidence demonstrating significant weight loss when used alongside diet and exercise.
Who is eligible for prescription weight loss medication on the NHS in the UK?
Generally, adults with a BMI of 30 or above, or 27 or above with weight-related health conditions, may be eligible. Eligibility is assessed individually by your GP or a specialist weight management service. Access varies by region, and waiting lists can be lengthy in some areas.
How much weight can you lose with prescription weight loss injections?
Clinical trials show average weight loss of approximately 15–21% of body weight with GLP-1 and dual GIP/GLP-1 medications, though individual results vary significantly. Weight loss depends on the specific medication, dose, your starting weight, diet, and physical activity. Use our weight loss calculator to explore potential outcomes.
Can I get prescription weight loss medication privately if the NHS waiting list is too long?
Yes. Private online prescribing is available in the UK through GPhC-registered pharmacies and UK-licensed prescribers. You can access prescription weight loss injections without an NHS referral, though you'll pay privately. Costs typically range from £129–£320 per month depending on dose and provider.
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.