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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Do Cold Showers Help With Weight Loss?
Cold showers may have a modest effect on calorie burning and metabolism, but the evidence is limited and the impact is small. While cold exposure activates brown fat and can increase energy expenditure slightly, it's not a reliable weight management strategy on its own. For adults in the UK seeking effective weight loss support, prescription medications and lifestyle changes offer more substantial, evidence-based results. This guide explores what the science actually shows about cold showers and the practical weight management options available through the NHS and private prescribing.
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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 looking for weight management in the UK, prescription medications offer clinically proven support for eligible adults. Three medications are currently licensed for weight loss:
- Mounjaro (tirzepatide) — a dual GIP and GLP-1 injection. Clinical trials showed an average weight loss of 15–21% of body weight at the maximum dose, taken once weekly.
- Wegovy (semaglutide) — a GLP-1 injection with an average weight loss of around 15% body weight in trials, also taken once weekly.
- Saxenda (liraglutide) — a daily GLP-1 injection, typically producing 5–clinically studied weight loss.
All three are prescription-only and require a clinical assessment to confirm eligibility. You can use our GLP-1 weight loss calculator to estimate potential results at different doses. The most effective approach combines medication (if eligible) with a reduced-calorie diet and increased physical activity.
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 through the NHS is available through specialist tier 3 weight management services — not from your standard GP. Access requires a referral and assessment, and availability varies significantly by region. Many areas have long waiting lists.
Private prescribing is faster: you complete an online clinical assessment with a UK-licensed prescriber, and if approved, your prescription is dispensed by a GPhC-registered pharmacy. Eligibility criteria are the same: BMI 30 or above, or BMI 27–29.9 with a weight-related condition (high blood pressure, type 2 diabetes, sleep apnoea, etc.).
Start by speaking with your GP about your options. Use our BMI calculator to check your current BMI and understand where you stand relative to eligibility thresholds. Your GP can advise on NHS access in your area or discuss private options.
- 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 cold showers actually burn fat?
Cold exposure does activate brown adipose tissue, which burns calories to generate heat — a process called thermogenesis. However, the effect is very small: studies suggest cold showers might burn an extra 100–150 calories per day at most. This is negligible compared to a 500 kcal daily deficit needed for sustainable weight loss. Cold showers are not a reliable weight loss method.
What's the difference between Mounjaro and Wegovy?
Both are once-weekly injections approved in the UK for weight loss. Mounjaro (tirzepatide) works on two hormone pathways (GIP and GLP-1) and produced an average 15–clinically studied weight loss in trials. Wegovy (semaglutide) works on one pathway (GLP-1 only) and produced around 15% average weight loss. Both require a prescription and clinical assessment. Your prescriber will advise which is more suitable for you.
Am I eligible for prescription weight loss medication in the UK?
You may be eligible if you have a BMI of 30 or above, or BMI 27–29.9 with a weight-related condition such as type 2 diabetes, high blood pressure, or sleep apnoea. For people of South Asian, Chinese, Black African, or Black Caribbean heritage, lower thresholds apply (from BMI 27.5). Speak with your GP or a licensed prescriber for a personal assessment.
How long does weight loss take with GLP-1 medication?
Most people see gradual weight loss over weeks 4–8 after starting. Maximum weight loss is typically achieved after 16–20 weeks on the maintenance dose. Results vary significantly between individuals. Weight loss medication works best alongside a reduced-calorie diet and regular physical activity — medication alone is not enough.
What if I don't qualify for prescription weight loss medication?
If your BMI is below 30 and you don't have weight-related health conditions, focus on sustainable lifestyle changes: a balanced, calorie-controlled diet, regular physical activity, and behavioural strategies. The NHS Weight Loss Plan and local weight management services (tier 1–2) offer free or low-cost support. Speak with your GP about what's available in your area.
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.