On stage at a sales convention, XanGo executive Joseph Morton said that when he first stumbled across mangosteen, a tropical fruit with purported curative powers, "I didn't have to have it confirmed in the New England medical journal before I would listen."

more stories like thisThe multilevel marketing company has built a huge business around its mangosteen-based juice, which it promotes as an immunity booster. The company still hasn't proved its health benefits - which it says could include a stronger immune system and improved joint function - to skeptical experts. XanGo's website includes a disclaimer, noting the juice is not meant to treat or prevent disease. A lab test arranged by The Associated Press found its antioxidant power to be on par with other fruit juices.

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