Researchers also found the combination improved lipid and blood pressure profiles and was well tolerated by patients.
The studies were presented at the International Congress of Obesity in Sydney, Australia.
Lead investigator Dr. Vidhu Bansal of GlaxoSmithKline Consumer Healthcare tells Reuters Health the studies demonstrate that orlistat "is an excellent candidate for over-the-counter (OTC) use for weight loss."
Orlistat 60 milligrams, also referred to as Alli, is a watered-down version of Xenical, made by GlaxoSmithKline. It is currently being reviewed by the Food and Drug Administration.
Xenical is the name for the orlistat 120 mg capsules and will be available with a prescription.
Orlistat blocks the body from absorbing about 25 percent of consumed fat.
Bansal says it is indicated for people "18 years of age and older who are overweight and committed to losing weight and making the dietary changes that will be needed to be successful."
The three studies involved 1,729 overweight participants. They were placed on diets that were 30 percent fat, 20 percent protein and 50 percent carbohydrate. Some of them took 60 milligrams of orlistat as well.
After six months, nearly 50 percent of those taking orlistat lost 5 percent or more of their body weight. This is nearly double the 26 percent who lost weight solely by dieting.
