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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Online Personal Trainer For Weight Loss — UK Options
An online personal trainer can provide motivation and exercise guidance for weight loss, but prescription weight management medications may also support your journey if you're eligible. In the UK, licensed options like Mounjaro and Wegovy are available through NHS specialist services or private prescription, alongside lifestyle changes. This guide explores how trainers fit into your overall weight management plan, what prescription options exist, and how to find out if you qualify.
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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 Prescription Weight Loss Medications
If you have a BMI of 30 or above, or 27–29.9 with weight-related health conditions, you may be eligible for prescription weight loss medication in the UK. The main licensed options are:
- Mounjaro (tirzepatide) — a once-weekly GIP and GLP-1 injection. Clinical trials showed participants lost an average of 15–21% of body weight over 72 weeks, alongside reduced-calorie diet and increased physical activity.
- Wegovy (semaglutide) — a once-weekly GLP-1 injection. Clinical trials demonstrated average weight loss of approximately 15% body weight at the maximum dose.
- Saxenda (liraglutide) — a daily GLP-1 injection, though less commonly prescribed than the weekly options.
These are prescription-only medicines requiring a clinical assessment before being prescribed. Individual results vary, and medication is typically used alongside diet and exercise, not instead of them.
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: Refer to your GP to request assessment by a tier 3 specialist weight management service. Eligibility criteria apply, and availability varies significantly by region — waiting lists can be lengthy in many areas.
Private route: Access through GPhC-registered online prescribing services. You'll complete an online health assessment with a UK-licensed prescriber, who will assess suitability. If approved, a prescription is issued and dispensed by a regulated pharmacy.
Whether you work with an online personal trainer or consider prescription medication, start by speaking to your GP about your weight management goals. They can advise on options best suited to your health profile and help you access NHS services if appropriate.
- 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.
Can an online personal trainer help me lose weight?
Yes. Online trainers provide structured exercise programmes, motivation, and accountability, which are all important for sustainable weight loss. However, weight loss also depends on diet, sleep, and other lifestyle factors. For best results, combine training with a reduced-calorie diet and consider speaking to your GP about your overall weight management plan.
What's the difference between Mounjaro and Wegovy for weight loss?
Mounjaro (tirzepatide) is a dual GIP and GLP-1 receptor agonist; Wegovy (semaglutide) is a GLP-1 agonist only. Clinical trials suggest Mounjaro may produce slightly greater average weight loss, but individual results vary significantly. Both are prescription-only and require a clinical assessment. Your GP or prescriber will advise which suits your circumstances.
Am I eligible for prescription weight loss medication on the NHS?
You may be eligible if you have a BMI of 30 or above, or 27–29.9 with weight-related conditions like type 2 diabetes, high blood pressure, or sleep apnoea. South Asian, Chinese, Black African, or Black Caribbean adults may have access at lower BMI thresholds. Speak to your GP about referral to a specialist weight management service in your area.
How quickly will I lose weight with Mounjaro or Wegovy?
Clinical trials showed average weight loss of 15–21% (Mounjaro) or approximately 15% (Wegovy) over several months, but this varies widely between individuals. Weight loss typically progresses over weeks and months as your dose increases. Combined with diet and exercise, results are best achieved over a longer timeframe rather than rapid loss.
Can I use an online personal trainer while taking weight loss medication?
Yes. Prescription weight loss medications work alongside lifestyle changes including diet and exercise. An online trainer can provide structured, safe exercise guidance. Always inform your trainer and GP about any medication you're taking, and start exercise gradually if you're new to training or managing a health condition.
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.