She does use dry shampoo "for the volume" but that wouldn't make it dark. It does seem fairly obvious that she's recently colored her hair. Actually in the video where she randomly insists she hasn't colored her hair, and the video before that, you can see her hair is MUCH darker than it was in the jenny craig taste tests videos. I'm talking about the top where people pointed out it was thinning, not the ombre horse tail she hadn't cut off yet. I don't know if she used actual boxed hair dye, or that color-in-a-can stuff trump uses, but you can see the texture of it sitting on her hair, I think I really noticed it in a video where she was braiding her hair in two stupid braids. But you can see the color sitting on her hair looks exactly like it does in some post-destiny videos after she had colored her hair. Either she's not rinsing it out well enough, or it's just temporary stuff that's collecting on her increasingly filthy hair. It's possibly dry shampoo residue that migrated from her scalp area, but that would explain the flat color, but not the darkness.