All perfect praise be to Allah, The Lord of The Worlds; and may His blessings and peace be upon our Prophet Mohammad and upon all his family and companions.
Tahara( ritual purity)is a condition for the validity of prayer. The Messenger of Allah(PBUH) said, " 'Allah does not accept any prayer without purification."{An-Nassai}. Among the conditions for the validity of Taharah, whether it was attained by Ghusl(ritual bath) or ablution, is that there should be nothing on the organs that should be washed in ablution(Wudu).
Al-Imam Annawawi(May Allah have mercy on him) said, "If he applied cream or the like to his dry coarse feet or painted them with Henna and a perceptible layer has remained, then he is obliged to remove it because it prevents water from reaching the skin. However, if no perceptible layer remained but only a trace like the color of the Henna, then it doesn`t prevent water from reaching the skin and the ablution is valid."{Al-Majmou` 1/426}.
Accordingly, if this "Keratin" prevents water from reaching the hair, then it must be removed in order for the ablution to become valid. However, if it didn`t prevent the water from reaching the hair, then it is permissible to perform ablution while having it. And Allah knows best.
