I used Zizyphus twice now and I'm quite happy with it.
4 tbs of zizyphus
1 tbs of aloe powder
1 tbs of fenugreek
1 teaspoon of henna mix (henna, amla, cassia, shikakai, brahmi, reetha, tulsi, bhringraj)

The addition of henna did not change my color, the whites are still there (I'm growing out henna hair and my roots are medium blonde) but it might be different for other people.