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).

338 JOURNAL OF COSMETIC SCIENCE 5 5 5 5 4.5 4.5 • 4.5 • 4.5 4,5 / • 3ø5 3 3 // 3 3 1 2 3 4 5 6 7 % ATTRIBUTES Without Coconut Oil [] With Coconut Oil us Prcwush I Figure 11. Effect of coconut oil on cosmetic attributes of bleached hair (in vitro panel test): Protective effect in improving appearance, fiber is swollen. Introduction of this hydrophobic component reduces the swelling propensity of the cuticle, which limits the upward curving of the surface cuticle. This reduces the chipping away of the cuticle cells, which reduces protein loss, as observed in this work. Because of its low molecular weight (-1000) the oil may also penetrate the cortex. Once again, because of the introduction of hydrophobic functionality into the fiber, the WRI is reduced. Reduction of water absorption and associated swelling seems to be the dominant mechanism of protection from the coconut oil. Lubrication provides an ad- ditional level of protection in grooming processes. CONCLUSIONS This study has firmly established the protective effect of coconut oil on hair damage in grooming processes when it is used as prewash conditioner. It also has a protective effect on chemically treated hair and hair treated with boiling water (i.e., hair in water at 100øC for 2 hr). The hydrophobicity of coconut oil seems to be responsible for this effect. Coated on the fiber surface, it can prevent or reduce the amount of water penetrating into the fiber and reduce the swelling. This in turn reduces the lifting of the surface cuticle and prevents it from being chipped away during wet combing. A reduction in the WRI is additional evidence for the decrease in water absorption. In addition to its protective effect, coconut oil seems to improve a number of cosmetic attributes of hair. Other benefits of this natural prewash hair conditioner are under investigation. ACKNOWLEDGMENT The authors would like to thank Dr. Yash Kamath, Director of Research, T.R.I., Princeton, New Jersey, for his valuable guidance in writing this paper.