Ethyl butylacetylaminopropionate is an insect repellent whose trade name is IR3535 and was developed and commercialized by Merck KGaA (Germany).

[4][5][6] IR3535 is effective in repelling several different insects such as mosquitoes species and also midges, ticks and head lice.

[7][8] A 2013 review concluded that IR3535 is as effective as 20% DEET against Anopheles, citing that some studies reported possibly shorter protection of just 3.8 hours.

[15] The mechanism of action is still under investigation, but it probably related to the intolerance of mosquitos and other invertebrate animals to its odor.

[2] IR3535 is approved by several authorities around the world, including ECHA (Europe)[17] and the EPA (US)[18] where it is considered a biopesticide.