I'm the natural mosquito repellent...

I got bitten like crazy by mosquitoes this past July 4th. It's my own fault because I don't like to use insect repellent because I don't want to absorb stuff like DEET through my skin. Besides, when I've actually succumbed to using mosquito repellent, I still get bitten. N,N-diethyl-meta-toluamide (DEET), the active ingredient in the most effective insect repellent formulations, is absorbed through the skin in varying amounts depending on its concentration and the presence of other chemicals (such as alcohol) in the product. Furthermore, once in the body, DEET can cross the placenta in pregnant women. Now if I were going to be in an environment where there was a very high risk of catching mosquito-borne illnesses, like West Nile Virus, malaria, or encephalitis, then I would use it, since the benefits outweigh the risks.

In any case, I was the mosquito repellent for everyone else at the party, since all the mosquitoes were attracted to me... Now, recently, I got excited when I saw the ads for the new OFF! Clip On Mosquito Repellent. What a great idea, I thought. The device is pretty simple. The "refills" consist of a piece of paper that has been impregnated with the active ingredient, and a little battery-powered fan disperses the repellent in the air around you. Then I wondered what the active ingredient was. Metofluthrin. Metofluthrin vaporizes pretty readily at room temperature, which makes it ideal for this application. Then I looked more carefully at the EPA report on the chemical, and was somewhat disturbed to find that it has been classified as "likely to be carcinogenic to humans." Great. If this is indeed the case, I'm not sure I want to be breathing in this stuff as it's dispersed in the air around me. It's still a relatively new chemical, so who knows?

Here's the California Department of Pesticide Regulation Public Report on Metofluthrin.

How well does the OFF! Clip On mosquito repellent work? People I know claim that it works well only if you're not moving too much. For example, wearing it while walking your dog will probably not work too well, because by the time the repellent has been dispersed in the air around you at any given moment, you will have moved away from that location...

There are some plant-based mosquito repellents, such as citronella, geraniol, p-menthane-3,8-diol (from eucalyptus), and soybean oil, but just because they seem more "natural" doesn't mean they're healthier. They also have their own health risks.