Board Thread:Episode Discussions/@comment-25319479-20160512105958/@comment-734582-20160516105430

Elveonora wrote: Well, I think even though humans had no chakra before and no chakra circulatory/pathway system, they still had physical and mental energies in them, there was just no way for them to get merged and chakra to get produced in the bodies. Presumably, yes. I think Hagoromo simply freed up people's spiritual energies in order to connect them, but people used that spiritual power to create chakra.

JouXIII wrote: @Thekillman Momoshiki and Kinshiki used pills, true. Kaguya, however, we don't know. Presumably she did. The Boruto Movie confirms the existence of at least one other Shinju, and thus one other fruit. Connecting the dots, it seems that they cultivated shinju to turn the fruit into pills (which is why it was forbidden to eat the fruit). It definitely explains how they traveled between worlds, using the pills.

The only real question is whether Kaguya got here herself, or whether she was sent by other otsutsuki. Either way, they seem to have ran out of pills, and Kaguya basically went against the plan and ate the fruit herself.