Shih Tzus have a double coat, consisting of a long outer coat and a dense, soft undercoat. The outer coat will grow continuously, and the undercoat will shed lightly, getting trapped in the topcoat, making frequent grooming essential to prevent matting and knots. This breed can handle both cold and heat thanks to its insulating undercoat. Lillian Ruff formulates de-shedding dog shampoo to maintain coat health for double-coated dogs.