Comment by Não Sei on The Hunter Wants to Live Quietly - Chapter 48

@Não Sei the white hair was probably a result of finally coming out of that dungeo. He's always had black hair even as J

@Miramini he dyes it, it is white

@supatsiu I know he dyes it, but I thought that the person was talking about before the dungeon. The beginning chapters made him look like his hair was naturally dark when he was initially activ

@Miramini looking at the beginning, I guess his hair has always been white, he's just been continuously dying it (his hair is probs crispy lol

@Não Sei This is my theory, you know there's a time when someone's hair color change to white when they under stress or experience an extreme pain. 
And J's hair turned white after he survived the dungeon, in which everyone but him died.

@Não Sei honey bee gave him some super expensive hair dye that she promotes. He does dye it black but it eventually starts going back to white

@Não Sei I read the novel, but it was a long while ago so it might not be accurate, but heres the big spoiler:
I'm pretty sure J has white hair because of the result of the apocalypse, where J is slowly becoming more of a monster and less of a human. He dyes it regularly after he woke up from the West Sea Rift. I think it only started changing colour when he was stuck within the dungeon. The apocalypse is a result of this world's timeline colliding with the world we saw in Yoon-Gaeul's fragments (i think...?) and it makes the outside world's enviornment become similar to what we saw in the dungeon they just went in, with the white snowish substance floating down and the desolite look.

@Não Sei he has grey hair but dues it to hide his identity

@Não Sei guys hes been actively dyeing it.... they literally showed us him dyeing it like yeah he used to have black hair but ever since waking up its been white and he needs to ontinue dyeing it. Uless im schizo and totally making this up but ive reread this so many times it has to be real...........

@Não Sei did u even read the manhwa ? He is constantly dying his hair