Thread:Yukine14/@comment-29218475-20161017191726/@comment-26175537-20161019121119

I've tried looking as well, and I indeed found that the style is confirmed to be natural.

I do agree it's definitely possible that his hair turned white later on, be it by the lymphoma or by trauma. Yet, I'm still thinking that should his hair have been brown, it would've at least gotten some sort of shade in the manga. The storywriter of the game also worked along with the manga, so I think it's safe to assume that it's in any case reliable. It could still be that his hair /is/ brown or red but that it's not shaded, though.

But, let's wait for the OVA and hope that we'll get more information! If we don't, I think Nagito's previous hair colour will kind of stay a theory.

Also, I'm not able to find the original post I got the information from, but I did find this from another Tumblr account: