– All-cis-4,7,10,13,16-Docosapentaenoic acid (all-cis-4,7,10,13,16-DPA) methyl ester, also known as Osbond acid, is an isomer of DPA and a more lipid-soluble variant of the free acid, primarily found in fish oils as an ω-3, 22-carbon fatty acid. Despite being an ω-6 fatty acid synthesized through the elongation and desaturation of arachidonic acid, its levels can decrease due to fatty acid desaturase syndrome, potentially impacting development. Additionally, increased expression of hepatic elongation of very long fatty acids protein 6 and elevated levels of very long-chain fatty acids, including all-cis-4,7,10,13,16-DPA, are indicative of nonalcoholic steatohepatitis, a condition that precedes hepatocellular carcinoma.