General Nutrition Center is an emporium of nutritional products. The stores carries its own brand of pill and powder supplements, and it offers a wide range of high-demand ones by manufacturers like CytoSport, MuscleTech, TWINLAB, SlimQuick, Gatorade and Met-Rx. When asked about his best advice to customers on staying healthy, a store manager responded, "take a multivitamin." GNC carries those, too.