Orlistat (Xenical / Alli)

Orlistat is a gastrointestinal lipase inhibitor that works locally in the gut to block the absorption of approximately 25–30% of dietary fat. It’s available both by prescription (Xenical) and over-the-counter (Alli) at a lower dose, making it one of the most accessible weight-loss agents. Orlistat does not affect appetite or central nervous system pathways, making it suitable for patients seeking a non-systemic approach. It’s most effective when used with a reduced-fat diet, as excessive fat intake can trigger bothersome gastrointestinal side effects like oily stools, flatulence, and fecal urgency. It remains a cost-effective adjunct to lifestyle modification.

• Manufacturer: Various (Rx Xenical; OTC Alli)
• Primary Use: Weight loss adjunct to diet
• Form: Oral

Common Side Effects

The most common side effects of Orlistat (Xenical / Alli) may include:

• Oily stools
• Flatulence
• Fecal urgency
• Abdominal discomfort

This is not a complete list. Always consult with your healthcare provider about potential side effects.