A preparation is disclosed for producing enhanced blood flow in tissue thus causing beneficial effects such as promoting hair growth on scalp tissuelacking sufficient hair, restoring normal sexual function in males with erectile dysfunction. Specifically, this is a preparation which provides local delivery of the amino acid L-arginine, an important biological precursor to the main substance which is responsible for relaxation of blood vessels permitting enhancement of blood flow. In the preferred embodiments, the L-arginine is provided so that it can be topically applied to the scalp or penis. The preparation also contains an agent which aids in the transfer of L-arginine into the tissue. In the preferred embodiments this agent overcomes the resistance to transfer caused by the high charge density of L-arginine. In the preferred embodiments this means is high ionic strength created by addition of choline chloride, magnesium chloride and sodium chloride. This preparation when applied nightly to scalp tissue lacking sufficient hairfor a period of time causes substantial growth of hair on the scalp. Further, when applied to the penis of a subject with erectile dysfunction causes restoration of normal sexual function.