MPEG2000-DMG is a large monofunctional PEG lipid containing a DMG group and a methoxy cap. The methoxy cap is inert while the DMG group is a popular ligand for developing PEG-lipids and lipid nanoparticles more broadly. Varying the size of a PEG linker greatly impacts its molecular dynamics, thereby affecting DMPK and ADME properties of a given API.