A product is considered to be a conditioner if it improves the quality of the surface to which it is applied, particularly if this improvement involves the correction or prevention of certain aspects associated with surface damage. Conditioning of the hair and skin must be a continuous process, as both substrates are in a constant cycle of shedding and renewal. The main difference between hair and skin is that skin is basically a living organ that replaces its outermost layer on a frequent basis. Hair, in contrast, is basically dead material derived from a few live cells deep within the skin surface.