Of the products tested, those containing DEET
provided the longest-lasting protection (Table 1). The
complete-protection times of DEET-based repellents correlated positively with the concentration of
DEET in the repellent. The formulation containing
4.75 percent DEET provided an average of 88.4 minutes of complete protection; the formulation containing 23.8 percent DEET protected for an average of
301.5 minutes. There was a statistically significant difference in complete-protection time between each
DEET-based repellent and the product with the next
higher concentration of DEET (P