Cortisol levels are correlated with stress and stress-induced illness, such as depression and anxiety.1 Analysis of cortisol concentration from hair samples is a standard technique in psychology. However, when testing human subjects' hair, many variables, including hair wash frequency, shampoo-type, chemical treatment, and hair strengtheners, may artificially alter the cortisol concentration.2 It is important to consider this when studying the cortisol levels in hair samples from the BIPOC community, where many commonly used products are sulfate-free. These shampoos are thought to be gentler on hair and remove less natural oil, which could lead to systematically higher measured levels of cortisol.3 Here, we will study how sulfate-free and sulfate-based shampoo-treated hair samples differ in measured concentration of cortisol using human hair samples that have been treated with each type of shampoo for several weeks. We aim to quantify cortisol levels using liquid chromatography-mass spectrometry (LC-MS) and will first determine an LOD and LOQ for our method. We hope our findings will highlight an important confounding variable in cortisol level studies and inform the community on ways to alter standard cortisol measuring practices to be more inclusive of all patients.