Board Thread:Naruto Discussions/@comment-34436445-20181208160828/@comment-1512913-20181211141407

There is no evidence that Sasuke's injection had anything to do with Zetsu, only Hashirama's cells were mentioned. Same for Naruto's prosthesis, Tsunade cultivated it from Hashirama's cells, not Zetsu goo. But then again, it's possible. Both Kabuto and Tsunade had access to White Zetsu stuff.

Regardless, even White Zetsu-modified Hashi cells would still allow Naruto and Sasuke to use Wood Release, so they should be listed as users no matter how you look at it and the only reason they haven't is due to stubbornness.

Also Yamato doesn't have Hashirama's cells, he has some of his DNA, different kind of procedure.