Probing calcium and sulfur distribution and pattern in hairs using micro-proton induced X-ray emission （MPIXE）
January 2007
in “
中国科学通报：英文版
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TLDR Women's hair has more sulfur, and black hair has more calcium than white hair.
The study used micro-proton induced X-ray emission (MPIXE) to analyze calcium and sulfur distribution in over 20 hair samples from several individuals. It found that sulfur content was higher in women, while calcium levels were significantly higher in the medulla core. Both male and female hair exhibited daily rhythms, and sulfur showed monthly rhythms along the longitudinal axis. A gradual decrease in sulfur content from tip to root was observed, and more calcium was deposited in black hair compared to white hair.