Hi, so my hair is naturally dark brown but for the past.. five years I've been using semi-permanent black hair dye. Six/eight months ago I decided I wanted to get it back to a dark brown so I've used 'darkest brown' semi-permanent dye twice since then so keep my roots looking OK with the rest of the hair.

My hair is quite long and I like it that way so I don't want to cut it, I think the stained hair might be a fraction lighter than it was but is still very black. I use head and shoulders shampoo which might be helping take it our a little.
If the choice is between keeping my hair black and healthy or lightening it a few shades but making it dry and losing its shine I'm not sure I would risk it..

Are there any options that would keep it healthy?