122 citations
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October 2010 in “Clinica Chimica Acta” The study investigated the effects of shampoo and water washing on hair cortisol concentrations using hair samples from 20 rhesus monkeys. It found that repeated washing, whether with shampoo or water alone, significantly reduced hair cortisol levels. This reduction was primarily due to water exposure, as cortisol levels after 20 water-only washes were similar to those after 20 shampoo washes. The findings suggested that repeated exposure to water can leach cortisol from hair, potentially leading to underestimation of chronic hormone deposition in hair cortisol studies. Collecting samples close to the scalp and considering hair washing frequency were recommended for accurate human hair cortisol assessments.
95 citations
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January 2007 in “Human biology” Human hair can be classified into eight types based on physical features, not ethnicity.
93 citations
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January 2007 in “Skin Pharmacology and Physiology” Caffeine in shampoo quickly enters the body through hair follicles.
69 citations
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January 2005 in “The Journals of Gerontology Series A” Short telomeres may cause symptoms like hair loss and osteoporosis, offering insights into aging.
67 citations
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April 2007 in “Journal der Deutschen Dermatologischen Gesellschaft” Shampoos are designed to clean and improve hair and scalp health, with specific ingredients for different hair types and conditions.