Uptown curls, Pure henna can be used on color treated hair - but not henna products with metallic salts. Always do a test first on a discrete section of your hair first before doing your whole head, though.
Nikki, my original plan was to henna once a month, and use cassia in between. But I got caught up experimenting with the henna. Now, you're making me want to return to my plan and use cassia as my deep conditioner lol.
It's funny how, with the mixing and rinsing, even though it's more work than taking a store bought conditioner and slapping it on, I still look forward to doing my henna treatment. I actually like the process - like a spa treatment. And the results definitely justify the effort.