How Insect Repellent Works

If you are heading outdoors, you know how aggravating bugs can be. The answer, of course, is to use insect repellent to keep them from biting. Ah, but how does insect repellent actually work?

Insect repellent is used as a catch-all term, but it really covers a subset of repellents based on their active ingredient used to keep the bugs off. There are chemical products based on ingredients such as DEET. There are also natural products using active ingredients such as Citronella and oils such as lemon eucalyptus. The chemical products tend to be toxic to some extent, so repellents with natural active ingredients are generally better for you.

Given the name, most people would assume insect repellent works by repelling mosquitoes, flies and so on. Some do, but some do not. Some insect repellents work by making you smell or taste bad to a bug. Other work by masking your skin odor. The process can be analogized to stealth plane technology. The bug uses its "radar" to identify tasty humans to bite, but you are hidden from the radar by the insect repellent.

If you wear insect repellent, it is important to understand there is a second reason you may get bit. While bugs are attracted to the odor of your skin, they are also attracted to another odor you give off. In this case, we are talking about the carbon dioxide in your breath.

Insect repellents tend to be effective over only short distances. As a result, you may see mosquitoes and other bugs flying fairly closely to you. This does not mean they are biting you, but it can lead to a sensation indicating they are. The best way to determine if you are being bit is to look at the spot where the sensation is occurring. If you are, then put more repellent on!

So, should you walk around lathered in insect repellent all day long? If you are in an area with a high concentration of bugs, then you should. That being said, the biggest risk time tends to be dusk or dawn. This is the feeding time for many bugs, particularly mosquitoes.

John Grimes is with All Terrain - makers of natural insect repellent for the outdoors.