I've always wondered how 
got their hair color. 
all definitely seem likes they got their hair color from magic/ powers of some sort. But don't really have powers. Also damn if hair-dye is a thing whoever is dyeing hairs in Piltover/ Zaun is dang insane at their job.
It's these sort of things that bring about funny ideas to me. If I were to bring out creative ideas as to why their hair colors are the way they are I would say;
It wouldn't be shocking to see Zaunites and Pilties use chemicals to change their hair color. Zaun is filthy, so character having their hair bleached for chemicals wouldn't be uncommon. If you don't want to appear as Zaun, maybe they would dye their hair with other chemicals.
I think it's safe to chalk down to that conclusion.
I would assume Fiora's hair to be a statement of her rejection of House Laurent's old ways.
It's safe to assume that Evelynn's hair is probably a result of her heritage/origins as inhuman.
Morgana's hair is a similar strain as Evelynnn. If you look at her Exiled skin you can see that her hair was originally a golden blonde color (The same color as Kayle's actually). Her Magic is of a dark purple color. You could assume the dark magic she uses has corrupted her body.
Varus's hair could be a case of Marie Antoniette Syndrome, or because of the corruption.
Elise's hair color could actually be natural. Vibrantly red hair of that shade is possible, it is however more common in people of African Descent.
Lastly we have Caitlyn, who's hair is more then likely an Art choice then being literally blue. When creating artworks, a stark black color needs to be avoided, as it can cause serious problems with colour composition in Artworks. Take for example, Wonder Woman's hair is very often being drawn as blue in the comics books, despite it being canonically black. It's as a result of colour restrictions and artistic choices that this is the case.
I'd say Caitlyn's hair is actually black, or a very dark brown colour, but has been coloured in her classic splash as with a blue shine to it, as to avoid having a dark void where her hair would be. The same idea applies to her in-game model, where if you had a stark black colour, it would not suit well when taking into account the lighting of the rift and could appear very stark (League of Legends models are light on the top and darker on the bottom).
A few other champions fall into the same situation as Caitlyn, such as 
and 
I mean, in a world where planet sized dragons can create stars out of sheer will and a man was transformed into a werewolf by chemicals, I don't think hair dye is all that strange. They might even be that colour naturally, aside from Jinx of course.
It's confirmed that while Jinx wasn't born with teal hair, it's permanent now.
Yes, hair dye is a thing and it's even better than the real life one - you don't have to re-dye it to keep the color - at least the Zaun one.
4/5 are from piltover and zaun. Those guys put metal, glass, and chemicals in their bodies for whatever reason they can argue.
i think they figured out and managed to market hair dye maybe just a little ways back.
is a Demacian
Or more hair color genes might be active in Runeterra
Ok, but one question remains...
WHAT COLOR IS 
HAIR?!? SERIOUSLY?
Who says it's dyed?
Even redheads don't have that deep of a red color in their hair.
