Board Thread:Theories and Speculation/@comment-45444155-20200806213256/@comment-1512913-20200812084446

That's because it wasn't, Sage Transformation is result of Jugo and his clan bodily fluid's reaction, Jiraiya didn't have any of Jugo's powers.

And who knows, only thing we know for sure, is that too much natural energy = bad shit happens, too little natural energy = Senjutsu chakra doesn't get made. Thing is, it doesn't really make sense for everyone to start turning into toad statues... so perhaps those who learned at Ryuchi Cave start turning into snake statues instead... Jugo doesn't turn into a statue, he just gets mentally unstable and Kabuto and Mitsuki, both who have Jugo's power as a base, don't suffer from this at all.