The first time I ordered henna I got indigo too intending to do a treatment with both. But I never used the indigo because other than the gray you can't tell I dye my hair. Still reddish brown like before. Plus I do add coffee/black tea which is recommended by Henna Sooq to get more brown than red.
"More people would learn from their mistakes if they weren't so busy denying them." - Harold J. Smith.