For the past 50 years, DEET has been the safest and most effective repellent available to fend off mosquitoes and minimize exposure to some of the diseases that they spread. A team of American chemists, however, have developed an alternative that lasts three times longer and might prove to be just as safe.

Looking for a replacement for N,N-diethyl-m-toluamide (DEET) has lead research chemists at the University of Florida and the US Department of Agriculture (USDA) to turn to acylpiperidines, an active ingredient in pepper, which has been found to repel mosquitoes in a laboratory setting for as long as 73 days, whereas the repellent properties of DEET usually last no more than 17 days. When using commercially produced DEET-containing products for personal application directly onto the skin, the products are most effective for only about five hours.

Further tests of the acylpiperidine-laced repellents are expected in order to determine how well the repellents last in a real-world setting, where evaporation, heat, and perspiration cause current repellents to break down and to determine any potential for skin irritation.

Mosquitoes spread diseases such as malaria, West Nile virus, and Rift Valley and yellow fevers throughout a wide swath of the world. Finding a safe effective mosquito repellent presents the possibility of saving thousands of lives every year.

The research team has published the findings of their study of acylpiperidines in Monday’s online issue of The Proceedings of the national Academy of Sciences.