I consider Cholesterol a MOISTURIZING not protein conditioner( it has protein but not enough to warrant the use of a moisturizer after) .. I use it a lot , never experience any hardness
http://www.longhaircareforum.com/showthread.php?t=92906&highlight=cholesterol
There are conditioners with protein in them, with such low concentrations of proteins relative to moisturizers and humectants, that they give an overall moisturizing effect. Humecto and CON Nourishing conditioner are both conditioners that contain protein, but yield an overall moisturizing benefit. So, though they contain protein-- they are still considered moisturizing conditioners.
The next level would be protein-based or "protein rich" conditioners. These are regular conditioners that contain higher amounts of protein, relative to their moisturizing and humectant-like agents. These conditioners are generally more "surface-acting", contain larger protein molecules, and yield less dramatic results than “reconstructors. †Protein-based conditioners rinse away/wear off easily in a few days/washes because they do not penetrate the cuticle layers deeply. LeKair Cholesterol, ORS Replenishing pak, and Mane N Tail come to mind for examples. Because their formulas do contain moisturizing/conditioning agents, a moisturizing conditioner may not need to be used afterward.
The final level would be the treatments/reconstructors. These contain the highest amounts of protein compared to moisturizing agents, and offer very little actual conditioning. The results of reconstructors are usually more dramatic and longer lasting than protein-based conditioners, because they tend to contain concentrated, smaller hydrolized proteins that can penetrate and bind to the cuticle layers a little more deeply. These also vary in protein concentration compared to one another, but as a whole tend to contain more protein than everyday protein-based conditioners. Aphogee 2 Min Keratin reconstructor is an example of a light end reconstructor, and of course the Treatment for Damaged hair is on the heavy end. Because their sole job is to "repair" and/or "reconstuct" these treatments don't offer much in the way of conditioning, and usually have to be followed by moisturizing conditioner.