Understanding weight
Is Obesity a Disease?
Understand how biology, health and everyday circumstances affect weight, and why long-term support can matter.
Understand obesity and long-term care →
For treatment information alongside these guides, see our weight loss medications overview.
Explore Weight Loss Medication Guides
Mounjaro
Guides covering side effects, dosage, diet plans, comparisons and practical support.
Wegovy
Guides covering treatment timelines, side effects, eligibility and support.
Weight-Loss Pills
Explore guides on oral weight-loss medicines, including Wegovy tablets, Foundayo and emerging treatment options.
New to Weight Loss Treatment? Start Here
Start with clear, practical information on how treatment works and its possible side effects, then use the calculators to understand your calorie needs and whether you may meet the usual starting criteria.
Beginner's guide
Weight Loss Injections Explained
Learn how GLP-1 weight loss injections work, how treatments differ and what to expect from assessment, results and side effects.
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Beginner's guide
Weight Loss Injection Side Effects
Understand the most common side effects, what may help and when symptoms need prompt or urgent medical advice.
Understand injection side effects →
Calculator
Weight Loss Medication Calorie Calculator
Estimate a practical daily calorie target using your height, weight, age and activity level.
Use the calorie calculator →
Calculator
BMI Weight Loss Calculator
Check your BMI and get an initial indication of whether you may meet the usual criteria for prescription treatment.
Use the BMI weight loss calculator →Cost & Value
Practical advice to help you understand treatment costs, compare options and make a safe, informed decision.
New & Emerging Topics
Clear, clinically responsible coverage of developing weight-loss treatments, research and safety questions.
Explore More Weight Loss Guides
Retatrutide Side Effects: What the Trials Show
Quick answer: The most commonly reported Retatrutide side effects in clinical trials have been nausea, diarrhoea, constipation and vomiting. Some participants have also reported altered skin sensations, while an earlier trial found a temporary, dose-related increase in heart rate. Retatrutide...