shampoo for thickening and softening bamboo fibers STRENGTHEN and THICKEN STRANDS: The strengthening formula in this 13-fluid-ounce bottle of Maui Moisture Thicken and Restore plus Bamboo Fibers Shampoo helps give brittle curls their maximum bounce back. Naturally curly hair care: The thickening shampoo is great for hair types ranging from wavy to tight curls. It also helps color-treated, transitioning, and natural hair types look renewed and nourished.