I was always told that you should NOT use Keraphix every week unless you have EXTREME damage.
I used to use the Nexxus products a few years ago and then on and off as recently as last year. I have stopped using them altogether because the products were not doing very much for my hair, and I learned that there are some damaging ingredients in a few of the products. They were good for a few uses, but my hair started to feel dry over time. I figure that the mineral oil in the Humectress may have been the culprit, along with the detergents in the Therappe shampoo.
My conclusion is that the Nexxus products were OK for occasional use, but prolonged caused my hair and scalp to feel dry (my opinion).
AngieK