I talk to anaesthetists though work and they say us redheads need more to be kept under. It’s my anecdotal experience with local as well, I always tell dentists and other non specialists that I need more than usual, they never believe me and then they have to give me additional shots later cuz it still hurts. Some try to perform the procedure anyway, which I usually can’t cope with, so I’m not so sure I can handle pain better than others.