A branched-chain ionizable cationic lipidoid; has been used in combination with other lipids in the formation of LNPs for the delivery of mRNA, siRNA, or saRNA; LNPs containing C12-200 and encapsulating an mRNA reporter selectively accumulate in the liver, and to a lesser extent in the spleen and pancreas, in mice; administration of human EPO mRNA or factor VII siRNA in C12-200-containing LNPs increases serum EPO levels and reduces factor VII serum levels, respectively, in mice