HAIR DAMAGE 45 .:. 0 • ::i::i•.:. '•::.• :i::•ii! :::!•, ' ...:11 :i:!,! .! i74• :.:.i:.! •:•-v. ::i•!•i :ii:! :i : i:. ..:: : 'i'i"• i:i::?. ??i :'.i: o.o '• ........................................................... •',',i,,j :. • :: .................................................... ' i:.•m: !':!i! .................................................... ill m I 2 3 4 5 Shampoo (Each value Is an average of three tressas. Observed diffarances are significant at p=O.05 level for all shampoos as tested above). Figure 1. Effect of various shampoos on post-shampoo protein loss from European hair during combing. provide superior hair protection during combing as shown above. For such studies, multiple hair tresses were shampooed either with the conditioning shampoo (shampoo 5) or with a non-conditioning shampoo (for normal hair), followed by conditioner 2 ... I 2 3 5 CONDITIONER (2in1 Shampoo) (Each value is an average of 3-5 tresses. Obsarved differencas ara significant at p=0.05 level behveen #5 vs. #1 and #2) Figure 2. Effect of various conditioners on post-shampoo protein loss from European hair during combing.

46 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS application @ 1 cc/tress). Results (Figure 2) show that protein loss during combing was significantly less (p = 0.05) from hair treated with conditioning shampoo 5 vs condi- tioner 1 or 2 the differences between shampoos 5 and 3 are, however, not statistically significant. Furthermore, the differences in protein loss among the three conditioners tested (shampoos 1, 2, and 3) are also not significant. This suggests that these three conditioners are very similar with respect to hair protection efficacy. EFFECT OF COSMETIC TREATMENTS ON PROTEIN LOSS FROM HAIR DURING COMBING Damage to hair from cosmetic treatments is well documented (1,3,16). As the hair weathers or is physically or chemically damaged (perming/bleaching), the scales begin to lift and partially detach from the fiber surface (3, 16). It has been shown that chemically damaging treatments such as permanent waves and bleach treatments in- crease interfiber friction and make hair more difficult to comb (8). We previously reported that the permed/bleached hair surface is more susceptible than undamaged hair to protein loss when such hair is shaken in water (12). Experiments were designed to test whether we could demonstrate greater protein loss due to combing from chemically damaged hair as compared to undamaged hair. To pursue our goal, two separate ex- periments were performed in which European hair tresses, prepared from a single bundle of hair, were tested for protein loss due to combing before and after chemical treatment. Damage to hair was induced under controlled laboratory conditions by perming followed by bleaching, using commercially available products as previously described (12). Un- damaged and damaged hair were conditioned in the manner described above by using two leading-brand conditioners (identified as conditioners 1 and 3, Figure 2) and a 2-in-1 conditioning shampoo (shampoo 5). The treated tresses were then subjected to protein loss measurements by the proposed methodology. Results of these experiments are summarized in Figure 3. As shown in the figure, protein loss during combing is significantly greater (p = 0.05) from the permed/bleached hair as compared to the same hair before the chemical treatments. This suggests that chemical treatments make hair more susceptible to damage from combing. These results support our previous observations on protein loss from shaking chemically damaged hair in water (12). Furthermore, statistical analysis of the data also show that, on undamaged hair, the protein loss from hair treated with test product 5 is significantly less (p - 0.05) as compared to test product 1, a leading-brand conditioner the differences in protein loss between 5 vs 3 and 1 vs 3 were not signif- icant. However, when the hair was chemically damaged, the efficacy of these three conditioners to protect hair against combing damage changed. Protein loss measure- ments suggest that following chemical damage, the superiority of product 5 over product 1 to protect hair against combing damage was lost, whereas product 3 was now found to provide significantly better protection over both 5 and 1. Therefore, these studies suggest that a conditioner that is found to show superior efficacy on undamaged hair may not provide the same protection against combing damage if the hair is chem- ically damaged by cosmetic treatments such as permanent waving and bleaching. It is well known that chemical damage to hair changes the surface properties. It is therefore conceivable that changes in the surface properties of hair due to chemical treatments not only make hair more susceptible to protein loss during combing but also change its substantivity toward different conditioners and the subsequent conditioning/protective effects.