Mosquitoes are attracted to humans and other warmblooded vertebrates by sweat and the heat from our bodies. It’s only the female of certain species of mosquito that will feast on our blood to feed her offspring and the only way you can stop her from doing that, thereby preventing an itchy bite and potential disease, is by making your skin a far less appealing prospect.
DEET is an acronym for a chemical compound that was developed by the US Army following World War II. Like many other insect repellents – both natural and synthetic – it essentially makes your skin a very nasty-smelling place for the mosquito to land and feed on.
It can be toxic in high concentrations, though as long as the DEET-based repellent is applied responsibly, it’s both safe and very effective.