Gray leap forward: Xi Jinping shows natural hair color in a rare move for Chinese politics
https://edition.cnn.com/style/article/xi-jinping-gray-hair/index.html
In countries where dictatorship is common, personal preference of the leader like dying hair is also related with political message.
It would be troublesome even for rulers to be regulated about such a trivial thing. But, for those who like to get aristocratic power would be able to tolerate those regulations.