More than 20 hair strands obtained from several people are analyzed by non-invasive micro-proton induced X-ray emission (PIXE) for probing calcium and sulfur distribution and pattern. The sulfur con- tent in woman’s hair along the longitudinal axis shows a monthly rhythm whereas the level of Ca is much higher in the medulla core and exhibits a daily rhythm both in male and female hair. The Ca content gradually decreases from the tip to the root position in the shedding process and more Ca can be found in black hair compared to white hair.
