A hydroxy fatty acid; has been found in LPS from P. aeruginosa and the PHA polymers produced by P. oleovorans; agonist of GPR109B, increasing intracellular calcium in human neutrophils; prevents lipolysis of human adipocytes and is upregulated in human plasma in response to a ketogenic diet; plasma levels increase 3.41-fold in human male runners following a treadmill run to exhaustion as well as in a mouse model of ASD fed a high-glycemic diet