I was curious so performed a brief search. What are your thoughts on this study, which suggests that cytochrome c oxidase is not involved in the effect?: https://doi.org/10.1016/j.jphotobiol.2019.03.015
I think your link is interesting, in that the group without the copper enzyme also benefited from red light exposure. The copper enzyme explanation seemed reasonable to me, but perhaps there’s better explanation for why people seem to benefit from red light exposure. Maybe the benefit from red light it multifaceted.