72 citations
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February 2011 in “American Journal of Biological Anthropology” The conclusion is that recognizing hair growth cycles can improve the precision of dietary and health assessments from hair analysis.
501 citations
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October 2008 in “Psychoneuroendocrinology” Hair cortisol levels can show increased stress during late pregnancy but only for up to six months.
68 citations
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March 1965 in “The BMJ” Hormones and genetics affect hair growth and patterns, with some changes reversible and others not.