Age-related testosterone declines can be detected in men’s fingernails

Testosterone plays multiple roles in the regulation of development, physiology, reproduction, and behavior. Age-related testosterone declines are expected in the population. However, measuring circulating testosterone is especially challenging since concentrations are labile, responding to social situations and challenges. Matrices that integrate long-term testosterone levels are therefore valuable as biomarkers of mean, as well as chronic exposures. Here we report on a simple method to extract and measure accumulated testosterone from human fingernails using commercial EIA kits. Further, we demonstrate known human testosterone sex and age trends. Our method is especially useful for quantifying testosterone in menâ s nails, where a small amount of matrix is required. Thus, this approach is a potential tool for biomonitoring endogenous as well as exogenous testosterone exposure. We suggest considering nails as an alternative matrix for quantifying other steroids as well.The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author