I am worried that they might build up in my lungs. I have been vaping it for two days. I originally mixed it to add to my juice. But I started vaping it strait. Just making sure it is safe.
You're vaping
STRAIGHT menthol juice??? ...as in menthol crystals dissolved in alcohol???
Man, that's hardcore.
I overdose on a lot of strong menthol juices, and I add a lot of Alien Visions' menthol drops to different pre-mixes, and I've felt no ill effects... but I can't imagine vaping straight menthol juice.
You get my vote for Menthol King.
But, to answer your question... Sorry, I have no idea if that's unhealthy or not.