Hair Thickening Fibre Hair Thickening Fibers instantly cover bald spots, thinning, and patchiness across your temples, part, crown, and sides. Get everything you need to transform fine, thinning hair in seconds. At Rayon, we are committed to delivering results you can actually see in the mirror. Our advanced hair powder fibers boast follicle-mimicking molecules that allow seamless blending and a real-hair finish you’d swear was nothing but natural.