Kombucha tea drinking makes my hair gradually return to dark, if I do it regularly for 6 months or so. It has come back in in multicolors, and thicker and healthier.
It is white/grey with little dark, but after 5 weeks, it is beginning to darken from the back to forward.
The theory is that the K. heals the area of the intestines where melanin is produced.
It may also be that it draws copper from the tea, now that you mention copper....
I would advise against taking copper as a supplement, such as the kind Twinlab makes.
Its a heavy metal, and bad news in that high concentrate.