Answer
In the Name of Allah, Most Gracious, Most Merciful.
All praise and thanks are due to Allah, and peace and blessings be upon His Messenger.
In this fatwa:
1- If this “keratin” prevents water from reaching the hair, then it must be removed in order for the wudu to become valid.
2- However, if it didn’t prevent water from reaching the hair, then it is permissible to perform wudu while having it.
Answering your question, the General Iftaa’ Department in Jordan, states the following:
Taharah ( ritual purity) is a condition for the validity of prayer. Prophet Muhammad (peace be upon him) said, “Allah does not accept any prayer without purification.” (An-Nasai)
Among the conditions for the validity of ritual purity, whether it was attained by ghusl (ritual bath) or wudu (ablution), is that there should be nothing on any organ that prevents water from reaching it.
Al-Imam An-Nawawi (may Allah have mercy on him) said,
“If one applies cream or the like to his dry feet or paints them with henna and a perceptible layer remains, then one is obliged to remove it because it prevents water from reaching the skin. However, if no perceptible layer remains 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-Majmu` 1/426)
Accordingly, if this “keratin” prevents water from reaching the hair, then it must be removed in order for the wudu to become valid.
However, if it didn’t prevent water from reaching the hair, then it is permissible to perform wudu while having it.
Almighty Allah knows best.
Source: www.aliftaa.jo