I think it's highly unlikely you're going to start growing hair on your fingertips, if that's what you're worried about. If you're worried about the small amount of absorption that could possibly occur via your fingertips, keep in mind you're slathering your scalp with the stuff anyway. I would take care with the S5 cream, however. I believe some degree of systemic absorption can occur if you regularly use too much (despite what the few, brief studies indicate).