336 JOURNAL OF COSMETIC SCIENCE X 60 z z LI.I 3o 20 (:• •0 .• o 55.03 •• 38.02 • 31.6 2 • 27.23 • 1'9,68 20,00 20.19 14.35 T • • -- 13.62 15,0 7 16.15 DaMco Straicjht Wavy Curly HAIR TYPES W(thout Coconut Oil [•'lWith Coconut Oil as Postwash ['-I With Coconut Oil as Prcwash Figure 8. WRI of bleached hair with coconut oil as a pre- and postwash conditioner. 80 74 ,•4 64.92 61.07 57,19 52,35 , 55•j 53.59 ß ß 49,15 39,12 x 70 60 50 40 30 20 10 0 De M½o 5trai cjht Way y C u rl y HAIR TYPES []Without Coconut Oil E•]With Coconut Oil as Postwash [--IWith Coconut Oil as Prcwash I Figure 9. WRI of boiling-water-damaged hair with coconut oil as a pre- and postwash conditioner. oil, it is possible that the molecules of the oil penetrate into the cuticle and probably even the cortex. This may also be the case with undamaged hair, although the effect is small. The reduction in the WRI must be due to the introduction of the hydrophobic triglyceride into the keratin structure.

HAIR DAMAGE PREVENTION BY COCONUT OIL 337 BENEFITS ON COSMETIC ATTRIBUTES This study was conducted in vitro on undamaged and bleached hair using coconut oil as a prewash conditioner. Three judges ranked the cosmetic attributes, which have been listed earlier. The rankings are shown in Figures 10 and 1 l, respectively, for undamaged and bleached hair. The beneficial effects of coconut oil are seen for most of the cosmetic attributes of hair. MECHANISM OF PROTECTION BY COCONUT OIL The histology of a cuticle cell and the mechanism of damage in wet combing proposed by Swift (4,5) is shown in Figure 1. Because of cross-linking, the exocuticle is brittle and does not swell. The endocuticle and the cell membrane complex have less cross-linking and therefore swell significantly. This effect produces the tendency for the surface cuticle cells to curve upward and break when pressure is applied with a comb. Recent studies of Ruetsch and Weigmann (6) confirm that the endocuticle and the cell membrane complex (CMC) are the loci of weakness and that fracture occurs when the fiber is extended. Chemical methods weaken the adhesion of the cell membrane complex between the cuticle cells. The degree of swelling of the cuticular layers is increased by disulfide cleavage and oxidation. This enhances the combing damage and protein loss, especially in wet combing, as observed in this study. Coconut oil is mostly a triglyceride of lauric acid and hydrophobic. Application of coconut oil as a prewash conditioner coats the hair and inhibits the penetration of water into the hair. A small part of it is also absorbed into the hair during the wash when the 5 5 5 5 4.5 4.5 5 4.5 6.5 4,5 4 • 4 4 1 2 3 4 5 6 7 ATTRIBUTES Without Coconut Oil r•With Coconut Oil Figure 10. Effect of coconut oil on cosmetic attributes of normal hair (i. vitro panel test).