I put gel in my hair in the morning to keep my hair in shape— is that a chatzitza for my tefillin (shel rosh)? By the time I put my tefillin on, it is completely dry. Does the same apply to hair spray?
Without getting into the issue if it is Lo Tilbash, regarding a chatzitza for tefillin there are different opinions about this. Although the person putting the gel or powder in his hair wants it there and it wouldn’t be chatzitza, however regarding tefillin, it should be directly on the head. According to some poskim this is learned from what the posuk says “al yodecha”, that it should be directly on the hand without anything in between, (and the same would apply to the head). Therefore l’chatchila one should be careful not to put gel in his hair.
Kaf Hachayim 30-47, Ohel Yackov Lo Yilbash pg.343. Kaf Hachaim 27-18 in the name of the birkei Yosef, Pischei Teshuvos 27-8.