Key metabolite of the ketolytic pathway generating acetyl-CoA. Stereoselective product of D-3-hydroxybutyrate dehydreogenase. Clinically and physiologically significant stereoisomer. Energy carrier from adipocytes to peripheral tissues during fasting or exercise. Endogenous inhibitor of histone deacetylases (HDACs) 1, 3 and 4. Ligand of free fatty acid receptor 3 (FFAR3; GPR41) and hydroxycarboxylic acid receptor 2 (HCAR2; GPR109B). NLRP3 inflammasome inhibitor. Prevents K+-efflux and reduces ASC oligomerization and speck formation.