I have also dyed hair normaly after henna with no problems, their is theory that henna coats the shaft of hair so hair look ticker but hair dye can't penetrate inside, I give up but one but not forever if I found henna without green color for freshens and sand added I shall use it again, where I live we have only egles henna(wich have 3%ppd), some no name, and now Lush caca but mixed with butter.