Board Thread:Theories and Speculation/@comment-44559522-20200130155655/@comment-43776375-20200130170604

Wood relase works by converting the chakra in life energy and Hashirama had good regenerative abilityes, he is supposed to rapresent yang, and goes well with the life energy

Naruto was full of the yang part of the fox and his regeneration was boosted up

Sozo saizei works by speeding up the cellular regeneration

So I'd say it's probable that medical ninjutsu has more to do with yang chakra than yin