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 Over The Counter in the UK
True over-the-counter weight loss products are limited in the UK — most effective weight management solutions require a prescription or clinical assessment. If you're looking to lose weight, the NHS recommends starting with lifestyle changes like reducing calorie intake and increasing physical activity. For those who need additional support, prescription weight loss medications like GLP-1 injections are available through NHS specialist services or private prescribing. Understanding your options — from self-help approaches to prescription treatments — helps you find the right path for sustainable weight management aligned with your health goals.
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.
What's Actually Available Over The Counter?
In the UK, genuine over-the-counter weight loss products are surprisingly few. Most supplements and herbal remedies lack strong clinical evidence for significant weight loss, and many are not regulated as strictly as prescription medications. Some over-the-counter options you may encounter include:
- Orlistat (Xenical, Alli) — A lipase inhibitor that reduces fat absorption. Available in lower doses without prescription, though prescription-strength versions exist. Evidence shows modest weight loss of around 2–3 kg more than diet alone.
- Caffeine and green tea supplements — Limited evidence for small, temporary weight loss benefits
- Fibre supplements — Help with satiety but not specifically licensed for weight loss
- Vitamin and mineral supplements — May support overall health but do not directly cause weight loss
The reality is that lifestyle changes — reducing calorie intake and increasing physical activity — remain the foundation of sustainable weight loss for most people. For significant weight loss support, prescription medications are considerably more effective than over-the-counter alternatives.
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.
Prescription Weight Loss Options — More Effective Alternatives
If over-the-counter options aren't delivering results, prescription weight loss medications offer substantially stronger evidence for success. In the UK, GLP-1 weight loss injections — including Wegovy (semaglutide) and Mounjaro (tirzepatide) — are prescription-only medicines licensed for weight management. Clinical trials showed these medications help adults lose an average of 15–21% of their body weight when used alongside reduced-calorie diet and increased physical activity. Access is available through NHS specialist weight management services (tier 3) or private online prescribing following a clinical assessment. Your GP or a licensed prescriber can assess whether prescription weight loss treatment is appropriate for you based on your individual health profile, BMI, and any weight-related health conditions.
- 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 you buy weight loss injections over the counter in the UK?
No. Medications like Wegovy and Mounjaro are prescription-only and require a clinical assessment before being prescribed. Access is through NHS specialist services or private prescribers — not over the counter.
Is orlistat available without a prescription?
Orlistat is available in lower doses (60 mg) without prescription as Alli, though prescription-strength versions (120 mg) are also available. Evidence shows modest results — around 2–3 kg more weight loss than diet alone over 6–12 months.
What's the most effective weight loss option available in the UK?
Prescription GLP-1 medications like Wegovy and Mounjaro have the strongest clinical evidence, with participants losing 15–21% of body weight on average. Combined with lifestyle changes, they're significantly more effective than over-the-counter supplements or orlistat.
How do I check if I'm eligible for prescription weight loss medication?
Adults with a BMI of 30 or above, or 27 or above with weight-related health conditions, may be eligible. Use our free BMI calculator to check your current BMI, then speak to your GP about referral to specialist services or exploring private prescribing options.
Should I try over-the-counter products before asking my GP about prescription options?
Not necessarily. If you've already tried sustained lifestyle changes without adequate results, prescription medications are often more effective. Discuss your weight loss goals with your GP — they can advise whether prescription treatment is appropriate for your circumstances rather than spending time on less-effective alternatives.
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.