Does coffee help repel mosquitoes?

Coffee is a favorite beverage of mankind, with obvious benefits that have been proven for centuries. And according to some recent online sources, coffee may also be a secret weapon against mosquitoes. So what's the truth?

Coffee helps repel mosquitoes?

The argument that coffee helps repel mosquitoes has been largely word of mouth, and the science behind it seems to be mixed up. Many people think that mosquitoes hate the smell of coffee and that caffeine is a natural insecticide (their tiny nervous system can't handle it). But unfortunately, repelling mosquitoes is not so simple.

Pouring coffee or sprinkling coffee grounds around the yard can reduce the number of mosquitoes that choose these areas to lay their eggs. However, this is not a guaranteed way to reduce the number of adult mosquitoes residing in your yard.

In theory, coffee contains diterpenes that can be toxic to insects. That's why you can use coffee grounds to repel mosquitoes, flies, beetles, and other pests. But actual studies show very little scientific evidence to support the theory that mosquitoes hate coffee so much that just smelling it keeps them away. As well as how much diterpenes concentration is enough to create an 'effective insect barrier'.

In other words, mosquitoes may not like the smell of coffee, but they are not completely afraid of it. Therefore, if you really want to protect yourself from mosquito bites, apply methods that have been proven to work. The use of coffee should only be an additional method of increasing effectiveness.

Marvin Fry

Update 25 May 2023