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
iHerb Store in the UK — What You Need to Know
iHerb is an online retailer based in the USA that ships herbal supplements, vitamins, and wellness products to the UK. Many UK residents use iHerb for health supplements, but it's important to understand how these products fit within NHS guidance and UK health information standards. This guide explains what iHerb offers, regulatory considerations, and how supplements relate to weight management and overall health. Always consult your GP before starting new supplements, especially if you're taking medications or managing health conditions like type 2 diabetes or weight-related concerns.
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.
How Supplements Fit Into UK Health Advice
The NHS advises that most UK adults can get essential nutrients from a balanced diet without supplements. However, certain groups may benefit from specific vitamins — such as vitamin D in winter months or folic acid during pregnancy. When considering herbal supplements from any retailer, including iHerb, remember that:
- Herbal products are not regulated as strictly as prescription medications in the UK
- The Medicines and Healthcare products Regulatory Agency (MHRA) oversees some herbal products, but many fall outside strict pharmaceutical oversight
- Quality and purity can vary between batches and suppliers
- Some herbs interact with medications or health conditions
- Supplements should complement, not replace, healthy eating and physical activity
If you're managing weight or metabolic health, focus first on NHS guidance around balanced nutrition and regular movement. Our free weight converter and BMI calculator can help you track your health metrics alongside any wellness decisions you make.
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.
Safety, Regulation, and When to Speak to Your GP
iHerb is a legitimate retailer, but as a US-based company, products may not meet the same UK standards as items sold by UK pharmacies. Before purchasing herbal supplements from any online source:
- Check if the product is on the MHRA register of traditional herbal medicines
- Discuss any new supplement with your GP, particularly if you have existing health conditions or take medications
- Be aware that some herbal products may affect blood sugar control or interact with weight management medications
- Look for third-party testing information on product pages
- Understand that postage times and import duties may apply to UK orders
Your GP or a registered dietitian can provide NHS health advice tailored to your individual needs. For practical health tracking, MyWeightCheck offers free tools to support your wellness journey.
- 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 iHerb safe to order from in the UK?
iHerb is a legitimate retailer, but as a US-based company, products may fall outside strict UK pharmaceutical regulation. Always check the MHRA register for herbal medicines before purchasing, and discuss any supplements with your GP — especially if you have health conditions or take medications that could interact.
Do I need supplements for healthy weight management?
Most UK adults can achieve healthy weight management through balanced nutrition and physical activity alone, according to NHS guidance. While some people benefit from specific vitamins, supplements should never replace the fundamentals of healthy eating. Our free BMI calculator and weight converter can help you track progress effectively.
What does the NHS say about herbal products?
The NHS recommends getting nutrients from food where possible. If supplements are needed, speak to your GP first. Some herbal products can interact with medications or health conditions. The MHRA registers traditional herbal medicines, so check the register before purchasing from any retailer.
Can herbal supplements affect weight loss or medications like Mounjaro?
Some herbal supplements may interact with weight management medications or affect blood sugar control. Always inform your prescriber about any supplements you're taking. For personalised UK health guidance on supplements and weight management, consult your GP or a registered dietitian.
How do I know if a product from iHerb meets UK standards?
Check the MHRA register of traditional herbal medicines for UK-approved products. Look for third-party testing information. Compare products available from UK-registered pharmacies as an alternative. Your GP can advise on quality and safety for your specific health needs.
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.