(all-Z)-6,9,12,15,18-Heneicosapentaenoic Acid Methyl Ester-d3 is the isotope labelled analog of (all-Z)-6,9,12,15,18-Heneicosapentaenoic Acid Methyl Ester (H245615); the methyl ester derivative of (all-Z)-6,9,12,15,18-Heneicosapentaenoic Acid (H245600) which is a 21-carbon, ω-3 fatty acid and a dietary precursor to eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). Also administered in a high dose for pain relief.