NANOGEN FIBRES ARE KERATIN - THE SAME NATURAL PROTEIN AS YOUR HAIR. THIS IS THE IDEAL MATERIAL FOR HAIR THICKENING FIBRES AS ONLY KERATIN HAS THE SAME DENSITY AND FEELING AS HAIR. OTHER HEAVIER FIBRES CAN WEIGH HAIR DOWN, MAKING IT LOOK FLAT AND UNNATURAL, OR MAY CAUSE IRRITATION AND ALLERGIC REACTIONS. MANY PEOPLE TELL US THEY HAVE AN ALLERGY TO SYNTHETIC MATERIALS LIKE NYLON AND EVEN FIND COTTON ITCHY, BUT KERATIN FIBRES ARE COMFORTABLE ALL DAY – AFTER ALL NO-ONE IS ALLERGIC TO THEIR OWN HAIR!