I only ever do henna glosses, but I make them fairly thick/concentrated and have never noticed any dryness from hennaing. Some things to note:
It is recommended to henna on damp hair, and just like with a dye uptake will be better if your hair is freshly washed (even if the uptake is different with henna than with a traditional dye). And find that although I henna for the extra thickness it gives my fine strands and easier detangling, not color, I still find it works best when I use my henna gloss on freshly washed hair as though it were a moisture treatment.
Henna glosses rather than straight henna can be a good way to avoid the dryness that some can experience with henna. You may not need as much in the way of moisturizing treatments if your hair is protein deficient as it is easy for protein deficient hair to become over moisturized and "mushy".
I can't speak to doing roots only as I only ever do glosses, and have auburn hair anyway so my hennaed hair isn't a vastly different color than virgin hair for me, but I'd recommend checking out the henna thread for information.
Lastly, DO NOT henna if you're unsure, there are ways of removing it, but they are difficult and not guaranteed. If it's a protein treatment you're after there are products specifically designed to help with that, and plain coconut oil can help too.
Good luck whatever you decide, and smart idea to strand test!
Bookmarks