I think it depends where you paint it, I painted 50 mg Lugol's on my head because I had a sensitive scalp, and it went straight to my thyroid which was deficient. I still feel a sore right side of my throat 3 to 4 weeks after stopping, and having a lot of emotional symptoms along with heart palpitations.
I wish I painted it on my heel so it could have worked through the body slowly, and fill in places with Iodine deficiencies before it went into my thyroid.
I also should have started painting with much less than 50 mg, hope I could have helped from my mistakes, good luck.