Does wash out hair dye damage hair?

I have natural blonde hair and I want to try something different. I want to permanently dye it but I know that damages hair and I eventually want my old colour back, and I'm trying to grow my hair out. I don't do anything to damage it but I was wondering if wash out dye would? My hair grows about 1/2 - 1 inch every six months. I trim and everything, it just doesn't grow, so doing anything to damage it is a big no no for me. Would wash out dye slow down the growing proses?