I dont really know the answer to that one but i know the technology is real and isnt fake. The fibres are just micro keratine fibres (the same substance your hair is made out of) that add thickness to your hair. It technically isnt fake hair, just fibres that give the illusion you have more hair when it fact your hair has just gotten thicker.
My hair hasnt thinned enoughed for me to consider this option yet so thats my reason, but i may still consider this one day if things get worse.