I want to know if my Wudu will be accepted, as I apply gel to my hair. So when I wipe the head with my wet hand, if I have gel in my hair, will this affect my Wudu.

All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad is His slave and Messenger. We ask Allaah to exalt his mention as well as that of his family and all his companions.

If the substance you are using is solid and impermeable that prevents water from reaching the hair then the ablution is not valid; you must remove it. If one performs ablution without removing the substance then his ablution is not valid.

If the oil or cream are not solid but they left only their impression on the body like brightness or moistness then the ablution is valid. In this case, the person should pass his hand over his all parts to be certain that the water has actually reached them since the oil or cream may prevent the water from the parts.

On the other hand, we inform the brother that generally gel is made from gelatin which consists of animal derivatives. If it is the case then its lawfulness depends on the animals, whether they slaughtered according to Islam or not, and whether the animals themselves were lawful or not?  Any part derived by a dead animal which is not slaughtered, or pork is forbidden. So using them or eating them is forbidden in Islam.

Allaah knows best.