Obesity is a chronic, multifactorial metabolic disease characterised by excess body fat associated with significant health risks including type 2 diabetes, cardiovascular disease, hypertension, sleep apnoea, and certain cancers. It affects over 40% of US adults (BMI ≥30) and is increasingly treated pharmacologically alongside lifestyle intervention. Anti-obesity medications act through diverse mechanisms: gastrointestinal fat absorption inhibition (orlistat), central appetite suppression (phentermine, bupropion/naltrexone — Contrave), glucagon-like peptide-1 receptor agonism (liraglutide — Saxenda; semaglutide — Wegovy), dopamine/noradrenaline reuptake inhibition with appetite suppression, or GLP-1/GIP dual agonism (tirzepatide — Zepbound).
Pharmacological treatment is considered an adjunct to — not a replacement for — reduced-calorie diet and increased physical activity. The most robust anti-obesity effect is seen with GLP-1 receptor agonists (semaglutide, tirzepatide), which achieve 15–22% mean body weight reduction in clinical trials. Orlistat (the only anti-obesity agent with both Rx and OTC forms) produces more modest weight loss (~3–5% additional vs lifestyle alone) but has a distinctly peripheral mechanism and no CNS effects, making it appropriate for patients who cannot use centrally acting agents.
Weight Loss Medications Available at Lucas Clinic
- Xenical / Alli (Orlistat) — pancreatic/gastric lipase inhibitor; blocks ~30% dietary fat absorption; OTC as Alli 60 mg and Rx as Xenical 120 mg capsules; safe long-term peripheral mechanism
Disclaimer: This page is for general informational purposes only and does not constitute medical advice. Always consult a licensed healthcare professional before making any treatment decisions. See our full disclaimer.