I use a henna-type permanent hair color-Bigen Permanent Powder Hair Color. I have used it for 6-7 years off and on, and each time I am never disappointed. I re-touch the NG about every 3 months, that's when my natural color (light-med. brown) becomes noticeable. I LOVE IT. I am looking to possibly try just natural henna/indigo to dye my hair black but thinking I'll do that after I use all my 2.5 boxes of Bigen. It takes 3 boxes to do my hair root to tip, about 1 box to touch-up. I could get out much cheaper with henna/indigo as far as getting more for the money.