Orlistat

Orlistat is the generic name of the weight loss drug Alli (or Xenical). It is a type of enzyme inhibitor which works by preventing some of the fats in food from being absorbed by the body.

Orlistat is an offshoot of lipstatin – a natural product which inhibits the action of pancreatic lipase. This product was first isolated from ‘Streptomyces toxytricini’ – a bacterium which is responsible for producing antibiotics and other well known forms of medication.

The ease of use and simplicity of Orlistat meant that it was developed into a drug to treat obesity rather than lipstatin. How does it work? Orlistat acts upon the gastrointestinal tract (GI): it binds itself to two enzymes found in this tract called gastric and pancreatic lipases.

These lipases normally break down fat globules (triglycerides) in food into fatty acids, ready for absorption by the body. But Orlistat prevents this from happening.

It inhibits this action to the extent that 25 to30% of fats are unabsorbed.

This unabsorbed fat is then expelled from the body via faeces. Orlistat is effective at promoting weight loss although this is more noticeable when combined with a diet and exercise programme. Other benefits include a reduction in high blood pressure and the prevention of the onset of type 2 diabetes.