In summary, we measured the optical properties of human skin using a compact THz spectrometer. Spectra were collected from 0.1 to 2 THz, and measurements were made at three regions: palm, ventral (inner), and dorsal (outer) forearm. For all skin samples, the results show that the index of refraction () decreases with frequency, and the values for the absorption coefficient () increase with frequency. All skin regions exhibited comparable optical properties; however, skin from the ventral forearm and that from the palm exhibits the highest and lowest index of refraction values, respectively. Furthermore, the index of refraction for palm skin and dorsal forearm is statistically significant at most THz frequencies. In addition, the index of refraction values varies the most between tissues in the 0.2 to 0.4-THz frequency range. We also show that for all tissues the absorption coefficient increases with frequency from roughly at 0.2 THz up to at 1.2 THz. These values are comparable to those reported in previous reports.7,8,11–13 Finally, in this work, we demonstrate the slope of the absorption coefficient curves are strongly correlated with the TEWL values for each skin region. This data suggest that THz spectrometers may be a useful tool for measuring the hydration levels of tissues.