In January 2001, we purchased a total of 16 products for testing,
choosing repellents with national, rather than local, distribution
(Table 1). Seven widely available botanical repellents were included
in the study. Multiple concentrations and formulations of DEET
are readily available. We chose and tested three DEET-based repellents
(ranging from 4.75 to 23.8 percent DEET) that we believe
represented the range of commonly purchased repellents in the
United States. We also tested a controlled-release 20 percent DEET
formulation to determine whether it had a longer duration of action.
The only synthetic repellent containing IR3535 (ethyl butylacetylaminopropionate)
that is available in the United States and three wristbands impregnated with either DEET or citronella were also
tested. Finally, we tested the efficacy of a proprietary moisturizer
that is commonly believed to have repellent effects.