Board Thread:Naruto Discussions/@comment-33156423-20170923231447/@comment-1512913-20170926184112

Exactly, so that means if humans had had physical and spiritual energies before, they would have also had chakra, since a certain amount is always present in the body before more gets molded, which means that they didn't have those since Kaguya and her sons started the whole chakra thing on Earth.