MANHATTAN BEACH, Calif., Sept. 1 /PRNewswire/ — On September 1st, leading weight-loss brand, the SENSA® Weight-Loss System will launch its products in 3500 GNC stores nationwide. GNC is SENSA®’s first retail store partner since its launch in 2008. Prior to GNC, SENSA® has been a leader in the online and TV shopping distribution channels. Developed by Dr. Alan Hirsch, the SENSA® Weight-Loss …