I used to have shockingly blonde hair as a kid (my grandmother's hair, her great grandmother was from Norway, so I mean THAT kind of super bleach-blonde. I missed out on the icy blue eyes though lol) but it went from that to "dirty dish blonde" then light brown/auburn and then getting darker and darker from there on out. And for the past several years it had been dark brown. Around the time I was already on T I noticed it coming in even darker than that to a kind of "soft black" variant. It now only looks brown when sunlight is on it, otherwise it looks more black.
I also seem to be one of those guys that developed oily (NOT greasy - if it's clean it's oily if its dirty its greasy, there IS a difference believe me) hair after T. Never had that problem before T and not that it's a problem, but I did absolutely have to stop using conditioner over it because that exacerbated it quite a lot. I also have to use selsun blue shampoo because anything else my hair doesn't like now. So I'm sure that also is playing with the color of it as well. When it's gelled or wet it's pure black too.
But yeah. My maternal grandfather had natural black hair (so not the blue-black type), and I do have his hair pattern genes (I'm talking body hair and hairline here, my dad definitely did not have the "M" hairline or body hair everywhere, nor was his hair ever as dark as mine either) so... I'm probably getting some of his hair color genes activating from the T. Or so I believe. He's the only one I know of who had blackish hair on either side of the family and I'm getting it only now and after T.
Hormone changes for me is what had always triggered my hair color to shift before (I mean from toddler to adolescent to teenager). So it's more than just likely that this is the reason for it changing again in my case.
My eye color has also changed but that has been subtler than the hair. They're hazel and always have been but they're just different now. There's more green than brown, but usually most people see them as brown unless the sunlight hits them, then they're more green. It's difficult to explain lol. Like, I know the base layer of my iris is brown but the green is now coming in more, over that so they look even darker but differently.
But yeah, check this out:
http://goaskalice.columbia.edu/why-do-blond-kids-go-brown"Hi Alice,
Why are some people born blonde but turn brunette as they get older?
Dear Reader,
People learn in school that hair color, like eye color, is determined by genes. Many think that everyone has one hair color gene, but that's not the case. Each person has several genes that determine his or her hair color, and different genes are active at different stages in that individual's life, resulting in changes in hair color. Our genes determine the level of pigmentation present in our hair (not to mention our eyes and skin).
When it comes to hair color, there are two types of pigment (melanin), called eumelanins and pheomelanins. Dark brown or black hair is a result of eumelanins, and pheomelanins are responsible for blond or red hair. The combination of these two pigments creates each individual's unique hair color, and the level of pigmentation changes depending on the genes that are active at that point in a person's life. Blond hair can turn brown, brown hair can turn darker brown, and red hair can turn auburn. And some people's hair even stays the same color.
Of course, most people also experience a change in hair color later in life, when their hair starts to turn grey or white as part of the aging process. This results not from a change in activity of specific genes, but the slowing down or ceasing of production of the enzyme that creates pigment."