The present invention provides compounds, compositions and methods that enhance the transfer of an agent into a cell. The agents can include polypeptides, polynucleotides such as genes and antisense nucleic acids, and other molecules. In some embodiments, the agents are modulating agents that can modulate a cellular activity or function when introduced into the cell. The compounds, compositions and methods are useful for introducing agents such as genes into individual cells, as well as cells that are present as a tissue or organ.