(This may work great on those who have not damaged their hair too much, such as those who only dye with semi-perm dye, or those who have not lightened their hair. I'm also only talking about the Clear Gloss, not the colors in the line.)
I write from my own experience, using it on hair that was lightened to a level 9 blonde, then dyed brown with permanent dye (you may know, there is no duller looking hair than this). I had hoped to use this product to add shine to my hair. I found the instructions a bit baffling. They implied that this was a dye or a diluter, and that it should be applied, left on for a few minutes, then rinsed out (not shampooed out). So I did a test on a big clump of hair near the front.
I found that not only did this add no shine whatsoever, it smelled terribly (it just smelled like dye), even after it was rinsed out. I did as it said, rinsing, not using shampoo, but I could smell my test strand for 2 days until I finally did shampoo my hair. If I had done my whole head the smell would have been quite terrible. Once my hair was shampooed, the smell was gone and all was well, but again, there was no added shine.
The lady at the beauty supply shop told me it was more of a leave-in type conditioner, that I could just apply to damp hair, comb through and style. I definitely wouldn't be doing that though - the smell - plus I couldn't be sure it was safe to leave it in and not causing damage.
I hope others who have used this product will use this thread to post their experiences if they have used it on less porous hair. I would imagine it was made to work great on somebody, and if I've used it wrong, do let me know!
Making metal barettes/concord clips hair safe, long hair style how to: http://alonghair.wordpress.com