Mice with isolated GH deficiency (IGHD) due to ablation of the GHRH gene or mutation of its receptor (Flurkey et al., 2001; Sun et al., 2013), as well as Ames dwarf (df/df) (with combined deficiency of GH, PRL, and TSH) and mice with global disruption of the GH receptor (GHRKO) (Aguiar‐Oliveira & Bartke, 2019; Bartke, 2011), live longer than their WT siblings. Here, PRL is linked to isolated congenital growth hormone deficiency.