Although I personally wear lipstick, I know people that don’t for tznius reasons.
AFAIK if it’s not meant to be eaten and derive benefit from ingesting it, it’s okay to apply kashrus-wise. (NOT talking about Pesach here.)
Lightbrite and many others might want to be machmir, but all things NOT being equal, it makes more sense to do so for tznius reasons vs. kashrus reasons. Even more so if one wears (or is tempted to wear) the bold colors trending nowadays.