Gel In Hair And Wudu
Originally we are required to wash our hands, but when we apply nail polish, we use ‘ masah ijtihad ‘ over a part that was required to be washed initially. Head however is not required to be washed originally, instead the original requirement is masah itself, therefore applying gel on the head and peforming masah over it will still meet the original masah requirement. Therefore, nothing additional is required in this regard.