Braun LR, et al. - Physicians designed this study to examine changes in fibroblast growth factor 21 (FGF21) during tesamorelin treatment and to explain the interplay between FGF21, growth hormone (GH) augmentation, and liver fat reduction in humans. FGF21 was significantly positively correlated with liver fat in HIV-infected individuals. FGF21 decreased in association with reductions in liver fat, gamma-glutamyl transpeptidase (GGT), and FIB4, implying that FGF21 was upregulated in the context of steatosis and steatohepatitis and was reduced when these conditions improved. Furthermore, these data recommended that tesamorelin improved liver fat via pathways other than increasing serum FGF21.