There was a post I saw on twitter about Mephenesin changing hair color from black to blonde, and in the study they speculated the copper enzymes were affected by the drug somehow.
(https://hero.epa.gov/hero/index.cfm/reference/details/reference_id/7500912)
GGf8KsEa8AEmyt8.png
It seems to be one of the first sedative/muscle relaxants to the point of paralysis. It seems to increase glycine and oppose excitatory amino acids. The drawback being it destroyed red blood cells, and it's discontinued from most places.
(https://stuff.mit.edu/people/london/guai.html).
This link has interesting sources in it, but some extrapolations I don't really like, like fibromyalgia being unrelated to excess phosphate. They then state it's more related to PTH, without the connection that excess phosphate increases PTH (in relation to calcium). In any case it's a reasonable read on the background I think.
A good start I think would be to understand the process of naturally light blond people having their hair darken as they grow older on a molecular level, and the interaction with copper enzymes. And then work in reverse.
