Hythiol-C is said to work well.
This is not applied on the skin. It is a tablet that is eaten, without side effects (they claim). The chemistry behind its formula seems to suggest it works.
Actually weird thing is when I was working in Japan and only for a year, my skin went a lot whiter naturally. My friends/family who visited me during that period noticed it too - so it wasn't just me looking at the mirror thinking what the XXXX happened. All returned to normal when I was back to Australia haha..
May have to do with weather, or the food? :O