yes, keratin treatment damage hair especially with frequent use or improper application because of the presence of a high percentage of formalin may cause redness and itching of the eyes and skin. There are some unsubstantiated scientific opinions that it may cause certain diseases in the long term.Many traditional keratin treatments contain formaldehyde which can cause respiratory problems such as coughing, wheezing, eye irritation, headaches, dizziness and sore throats.