Once a multipurpose product used only in the kitchen, apple cider vinegar has now become a hot-ticket ingredient in health, skin and hair care formulations. Now, Redken will launch the Redken Color Extend Vinegar Rinse in May. The product is designed to condition, smooth, strengthen and purify your hair with each use. The new treatment, designed to be used once a week for a few minutes, also rebalances hair’s pH and gently cleanses for enhanced smoothness and shine, according to Redken.   It i...