13-POHSA (palmitoleic acid esterified to 13-hydroxy stearic acid) is a type of branched fatty acid esters of hydroxy fatty acids (FAHFAs), which have recently been discovered as endogenous lipids whose levels are modulated by fasting and high-fat diets, and are linked to insulin sensitivity in mice. Notably, the concentration of 13-POHSA in the serum significantly increases in glucose tolerant AG4OX mice, a model that overexpresses the Glut4 glucose transporter in adipose tissue, suggesting its physiological relevance. Like other FAHFAs, 13-POHSA is believed to enhance glucose tolerance, promote insulin secretion, and exert anti-inflammatory properties, highlighting its potential importance in managing metabolic syndrome and inflammation.