The National Football League would not allow GNC to run its commercial during the Super Bowl because the supplement and vitamin retailer sells products containing two of 162 substances it has banned. Robert Moran, interim CEO at GNC, said a new marketing program to rebrand the chain made less of an impact than it would have if the company’s Super Bowl spot ran during the broadcast. GNC’s same-store sales fell 3.9 percent for the quarter ending March 31.