SELENOS and alopecia: While mice unable to express selenoproteins in epidermal cells (Sengupta et al., 2010) or in osteo‐chondroprogenitor cells (Downey et al., 2009) show age‐related alopecia and bone abnormality, knockout of glutathione peroxidase‐1, a major selenoprotein accounting for 58% of total Se in liver (Cheng et al., 1997), does not render the mice discernible aging phenotypes up to 20 months of age (Ho et al., 1997).