5 Best Hair Building Fibers - May 2022 - BestReviews Best Bang for the Buck XFusion Keratin Hair Fibers Economy Size Check Price Customer Favorite This is like "hair magic." Makes you look like you're having a good hair day after one application. Great for root touch-ups, thinning hairlines, and bald spots. Creates the look of fuller, thicker hair. No need for hairspray. Washes out easily.