Adsorption Properties of Hair 356 deposition of a lamellar liquid crystal structure or silicone oil will have this effect. Water Content and Moisturization To scientists familiar with the technical literature and principles outlined to date, the comments and demands of hair care consumers appear puzzling. Consumers worry greatly about the “drying out” of hair and subsequently demand products that provide “moisturization.” However, as shown above, it is recognized that many forms of damage actually lead to higher levels of water in hair. Therefore, to the hair scientist, the popularly used descriptor “dry- damaged hair” is actually an oxymoron. Similarly, when considering consumer demands, one observes that highest moisture content is attained when hair is allowed to equilibrate in high humidity environments, but this condition typically represents the very definition of “a bad hair day.” As such, there is a definite disconnect between “consumer language” and “scientific language,” where an individual’s self-prognoses and the technical root cause are indeed different. This point was dramatically illustrated by Davis and Stoffel,29 who equilibrated hair tresses at both 15% and 80% RH before presenting them to panelists (N=50) for evaluation. The isotherm shown earlier in Figure 1 demonstrates how hair contains approximately 5% moisture at 15% RH, while this value rises to around 17% at 80% RH. When panelists were asked to select the tress that felt most moisturized, approximately 75% opted for hair that had been equilibrated at 15% relative humidity. Namely, three out of four panelists rated hair with the lowest water content as feeling “most moisturized.” Similarly, the tresses equilibrated at low humidity also scored equally lobsided wins in terms of smoothness, being less tangled, and feeling less damaged. These findings dramatically illustrate how higher water content in hair overwhelmingly leads to considerably diminished sensorial properties. An explanation for these findings likely returns to the ability for water to induce swelling of the hair fibers, where higher water content produces