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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Calmi Ring Reviews and Weight Loss Medication in the UK
Calmi rings and similar wearables can track wellness metrics, but they don't directly cause weight loss. If you're looking to lose weight in the UK, prescription medications like Mounjaro and Wegovy are clinically proven options available through NHS specialist services or private prescribing. These GLP-1 injections work alongside diet and exercise to support weight management for eligible adults. This guide explains your options 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-Licensed Weight Loss Medications and How They Work
Wearable devices like Calmi rings monitor health metrics but don't replace medical weight loss treatment. For effective weight management in the UK, prescription medications have strong clinical evidence:
- Mounjaro (tirzepatide) — dual GIP and GLP-1 receptor agonist; clinical trials showed average weight loss of approximately 15–21% of body weight over 72 weeks when combined with a reduced-calorie diet
- Wegovy (semaglutide) — GLP-1 receptor agonist; STEP trials demonstrated around 14.9% average weight loss at the maximum 2.4mg dose
- Saxenda (liraglutide) — daily GLP-1 injection; typically produces modest weight loss of 5–10% body weight
All three are prescription-only medicines requiring clinical assessment. You can estimate potential outcomes using our free GLP-1 weight loss calculator above. Individual results vary based on adherence, lifestyle changes, and personal metabolism.
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 Access vs Private: Finding Your Weight Loss Path
In the UK, prescription weight loss medication is accessible through two routes:
- NHS: Referral to tier 3 specialist weight management services through your GP. Availability varies by region and waiting lists can be lengthy in many areas
- Private: Online consultation with a UK-licensed prescriber; if clinically appropriate, prescription dispensed by a GPhC-registered pharmacy. No NHS referral needed
To check if you're eligible, calculate your BMI using our free BMI calculator above. Adults with a BMI of 30 or above (or 27–29.9 with weight-related health conditions like type 2 diabetes or high blood pressure) may qualify. Your GP can assess whether prescription weight loss medication suits your health profile.
- 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 a Calmi ring help me lose weight on its own?
Calmi rings and similar wearables track wellness metrics like heart rate and sleep, which support healthy habits. However, they don't directly cause weight loss. Clinically effective weight loss requires a calorie deficit combined with lifestyle changes or, for eligible adults, prescription medication like Mounjaro or Wegovy alongside diet and exercise.
How do Mounjaro and Wegovy differ?
Mounjaro (tirzepatide) is a dual GIP and GLP-1 agonist with average weight loss around 15–21% in trials. Wegovy (semaglutide) activates GLP-1 only, with average weight loss around 14.9%. Both are once-weekly injections requiring prescription and clinical assessment. Individual results vary significantly.
What's my first step to access weight loss medication in the UK?
Start by calculating your BMI using our free BMI calculator on this page. If your BMI is 30 or above (or 27–29.9 with health conditions), speak to your GP about referral to specialist weight management services, or explore private prescribing options through a UK-licensed healthcare provider.
How quickly will I lose weight on prescription weight loss medication?
NHS guidelines recommend safe weight loss of 0.5–1kg per week. Clinical trials show Mounjaro and Wegovy users typically see noticeable results within 12–16 weeks when combined with a reduced-calorie diet and increased physical activity. Results vary between individuals.
Is prescription weight loss medication available on the NHS for everyone?
No. NHS access is through tier 3 specialist services and eligibility varies by region. You typically need a BMI of 30 or above, or 27–29.9 with weight-related health conditions. Waiting lists can be long. Private prescribing offers faster access for eligible adults without NHS referral.
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.