Shares of GNC Holdings (GNC -5.6%) and Vitamin Shoppe (VSI -3.3%) slide after the FDA cracks...

|About: GNC Holdings, Inc. (GNC)|By:, SA News Editor

Shares of GNC Holdings (GNC -5.6%) and Vitamin Shoppe (VSI -3.3%) slide after the FDA cracks down on companies offering supplements containing the stimulant DMAA. The agency claims the ingredient increases the risk of higher blood pressure and could lead to possible cardiovascular events if overused.