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

Abstract

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 divided into control and experimental group who used regular shampoo and Urtica cannabina (U.cannabina) extract 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 scalp hair of Mongolian females was three times lower than the global average. The average increase in trace elements may be considered to be due to the transfer of an element into the human scalp during shampooing. These results indicate that some trace elements in human scalp hair are not only associated with nutritional status and environmental factors, but cosmetic products can also affect the trace element composition. 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 control 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.