i voted other because i have been using henna consistently for about a year but i have never done a protein treatment... !!! shock and surprise. i have the protein in my cabinet but have never used it. anyway, recently, henna has thickened my strands. but in my earlier hennas, it would only give color. now, i give it longer time to release its dye (but i use an acidic mix. if you use water the dye will begin releasing immediately). i also use lemon juice, which many people have reported as drying (but it works fine for me...not drying, and i have fine 3c and 4a strands). also, it may take 3-4-5 times for the thickening effect to show up. it also depends on how often you henna because it can be a cumulative effect (depending on the amount of dye released, length of time henna is left in hair, etc). sooo, i think you just have to go for it and see what works for you. my hair is definitely thicker now that i use henna though. oh, and i'm natural