My tongue used to go numb within 5 minutes of putting the dye on. I stopped doing it two years ago and switched to henna.
I stuck a strand of my hair into a little bottle of tincture this morning. Nothing really happened. It came out soft but the colour didn't change. I've loads of hair and it's long, I didn't want to use all my Lugol's... so I ended up just putting henna on it (after bleaching some 'highlights' in) - so at least the colour is right!
FM-