DEET

DEET is available in the US in many formulations with concentrations of 5%-40% and 100%; higher concentrations present complete protection for a longer period of time, but the duration of effectiveness reaches a plateau at a 50% concentration. A long-acting DEET formulation, originally developed for the US Armed Forces (US Army Extended Duration Topical Insect and Arthropod Repellent, EDTIAR) is available in the US as Ultrathon (3M). Ultrathon contains 25% (in aerosol) or 33% (in cream) DEET in a polymer formulation, which prevents loss from the skin surface by absorption and evaporation. Studies have shown that it gives complete protection against mosquitoes for 6-12 hours.