I didn't buy the caffeine one, but I bought the BB cream concealer one that claims to fade dark circles. It does feel really nice and cool when I apply it, but it looks stupid because I still have a faint tan. So I don't know if it does anything yet, but I kind of doubt it. Would work as a nice concealer when I am paler though.
People don't want to accept the truth either because they don't want it to be true, or they are afraid it's not true.