This "spray on protein treatment" is one of the best products on the market! It does has to be rinsed out! You should also follow it with a moisturizing treatment. But hands down, if you are past due for your relaxer and need your hair to look like it has been relaxed or "straighter looking," then this is your product!
Redken CAT should be treated like a pure protein; so do NOT use it every week and DO balance it with a moisturizing conditioner. It works like the old "Dudley DRC-28" and the "Aphogee treatment" except it does not stink because it does not have the animal protein in it; no dryer heat nor dryer time is needed; and the application is an instant spray on, comb through, rinse out. You can use dryer time for your moisturizing treatment that you would use behind it if you would like or use an instant moisturizing treatment like the Uans crema.
Redken CAT strengthens, reinforces, and polishes the hair strands. It is great as a pre-relaxer treatment about a week before the relaxer is due. This is a professional use product. If you are using this at home, then you should let your stylist know as to not duplicate the protein treatments.
Please use this product wisely and around once a month if using a lot of heat styling. Please do not use this product nor any other "pure protein" on the same day as a relaxer. The "freshly relaxed" hair would absorb too much protein too quickly and may feel great temporarily while wet, but too much protein and dry hair is a recipe for breakage.
Most stylist charge extra for this treatment, but consumers are getting their hands on a lot of professional only products without a license to practice hair. Just don't overuse and communicate with your stylist. Also, please search for my article on "Moisture and Protein Balance."