Chapter 6 201 the analysis. One investigation determined that there were several differences in amino acids showing a deficiency in serine, theronine and excess tyrosine, phenylalanine and ammonia in African hair compared to Caucasian hair, while other studies indicated no such differences.1,20,25 In an internal L’Oreal study, 25 samples each of Caucasian, Asian, Latino and African-American hair were compared. All of the hair, with the exception of the African- American, was purchased from a vendor. The African-American hair was collected directly from subjects in the Chicago area after quality screening. Table 2 shows the results for the amino acids that varied between the Asian and African-American samples. The Caucasian and Latino samples were eliminated due to suspected quality issues. Table 2 Amino acids values for African American and Asian Hair (mean amino acid % ± confidence interval (CI) at 95%) Amino Acid African American N=25 Asian N=25 Aspartic Acid 5.73 ± .12 6.21 ± .05 Serine 9.41 ± .10 9.18 ± .06 Alanine 3.15 ± .03 3.27 ± .05 Valine 5.25 ± .04 5.37 ± .04 Leucine 6.51 ± .07 6.77 ± .05 Tyrosine 2.01 ± .11 2.44 ± .08 Phenylalanine 2.41 ± .03 2.49 ± .03 Lysine 2.84 ± .07 2.97 ± .04 Histidine 1.25 ± .05 1.07 ± .02 Proline 8.01 ± .22 6.73 ± .05 Various methods have been used to analyze the lipid content of hair, including extraction, FT-Raman, and more recently synchrotron infrared microspectrometry. The earlier methods involving extraction and chromatographic separation did not reveal any differences by class of lipids, (cholesterol, ceramides and fatty acids).28 While FT-Raman is an excellent tool capable of analyzing