The change of copper, zinc, iodine, and selenium contents in the scalp hair of healthy females and the efficacy of herbal extract shampoo treatment

We investigated shampoo-related changes in levels of some trace elements in the scalp hair of females and their impact on scalp skin properties. Sixty healthy women were divided into the con-trol and experimental groups who used regular shampoo and Urtica cannabina L. (U. cannabina) ex-tract shampoo, respectively. Scalp skin was examined using an electronic skin analyzer, and trichometric analysis was performed with a Folliscope. The collected scalp hair samples were digested and measured using inductively coupled plasma-mass spectrometry (ICP-MS). The average copper (p = 0.05), zinc (p = 0.0002), and iodine (p = 0.0004) levels increased notably, whereas the selenium content decreased slightly (p = 0.337) in the experimental group. We found that the average iodine content in the scalp hair of Mongolian females was three times lower than the global average. The average increase in trace ele-ments may be considered to be due to the transfer of an element into the human scalp during shampoo-ing. These results indicate that the composition of some trace elements in human scalp hair is affected not only by nutritional status and environmental factors but also by cosmetic products. The hair growth, diameter, and density gradually increased and were higher in the experimental group than in the control group. Scalp skin moisture, sebum, and pH values increased in the experimental group, whereas the con-trol group showed no notable difference. Herbal extracts may potentially support scalp hair growth and increase the hair density. This ability can be explained by the trace elements in the herbal extract, which may play a key role in inducing hair growth.