. "\"Any process that activates or increases the frequency, rate or extent of the chemical reactions and pathways resulting in the formation of interleukin-13.\" [GOC:go_curators]" . . "positive regulation of interleukin-13 biosynthetic process" . "positive regulation of IL-13 biosynthesis" . "positive regulation of IL-13 biosynthetic process" . "positive regulation of interleukin-13 anabolism" . "positive regulation of interleukin-13 biosynthesis" . "positive regulation of interleukin-13 formation" . "positive regulation of interleukin-13 synthesis" . "up regulation of interleukin-13 biosynthetic process" . "up-regulation of interleukin-13 biosynthetic process" . "upregulation of interleukin-13 biosynthetic process" . . . "activation of interleukin-13 biosynthetic process" . "stimulation of interleukin-13 biosynthetic process" .