HSD17B13, also known as Hydroxysteroid 17-beta dehydrogenase 13, is an enzyme predominantly found in the liver and plays a role in the metabolism of steroid hormones and fatty acids. It is part of the hydroxysteroid (17-beta) dehydrogenase (HSD17B) family, which catalyses the conversion of hydroxysteroids to ketosteroids and the reverse. HSD17B13 is crucial for fatty acid metabolism, especially in the oxidation of long-chain fatty acids, and is localised to the peroxisomes — cellular organelles tasked with fatty acid processing. Its enzymatic function is vital for converting long-chain fatty acyl-CoAs into 3-ketoacyl-CoAs, supporting liver health and lipid metabolism.