Do natural insect repellants work?
The answer, we can already go ahead, is a bit complicated. Two of the three active ingredients that have regularly earned recommended status in our insect repellent ratings (picaridin and oil of lemon eucalyptus, or ALE) are either derived from plants or synthesized to mimic the chemicals in plants. But several other plant-based chemicals, including lemongrass and soybean oil, generally finish at the bottom of our ratings.
The Natural Products Association, a trade group, has defended those low-scoring insect repellants, noting that there is variation in the effectiveness of all repellants, natural and synthetic.
But the discrepancy between what works and what is no less random than that statement suggests. An EPA registration means that the product has been evaluated by federal regulators to ensure its safety and efficacy. The agency requires this verification for some chemicals, such as deet, picaridin, and oil of lemon eucalyptus, but not for others.
Below is a quick breakdown of which compounds are EPA registered, which ones are not, and what our tests showed.
Lemon Eucalyptus Oil (ALE)
What is it? It is important not to confuse this product with oil of lemon eucalyptus. The names are very similar, but the two chemicals are quite different. ALE is an oil extracted from the gum eucalyptus tree (native to Australia); the extracted chemical is called PMD and has proven effective as an insect repellent.
Lemon eucalyptus oil, by contrast, is distilled from the leaves and twigs of the lemon eucalyptus tree. The distilled product contains several botanical substances, including citronella and a very low and variable amount of PMD.
Works? In our insect repellent tests, two products, Repel Lemon Eucalyptus insect repellent and Natrapel Lemon Eucalyptus insect repellent, earned our recommendation. However, none of these are labeled for use against ticks. If you know that you will potentially be exposed to ticks, you may want to choose a repellent that contains picaridin, two active ingredients in our other recommended repellants.
It is safe? The EPA classifies PMD as a biopesticide, which means it is subject to more safety testing than botanicals (see below), including oil of lemon eucalyptus, but less testing than synthetic chemicals such as deet and picaridin. . Both federal regulators and our experts agree that OLE is relatively safe.
OLE is not as well studied as other repellent ingredients. But the research we have suggests that adverse reactions are limited to irritation to the eyes and skin. ALE should not be used in children younger than 3 years old, in part because research on ALE in young children is lacking (both deet and picaridin are considered safe for use in children older than 2 months).
What is it? Picaridin is a chemical that is synthesized (that is, made in a laboratory) to mimic a compound found in bell pepper plants. Available as an insect repellent in the US since 2005.
Works? Sprays containing 20 percent picaridin performed well in our tests, but a wipe and lotion made with that concentration scored low. We don't know why picaridin seems to work better as a spray, says Joan Muratore, who leads bug repellent trials at CR, but it's probably wise to skip the wipe or lotion formulations of this ingredient.
It is safe? Picaridin can cause eye and skin irritation, but this is probably rare. In an analysis of poison control calls related to insect repellants, picaridin caused only a few problems, and almost none required a visit to the doctor's office or the emergency room.
What are they? Botanical repellants, which often have "natural" on the product labeling, can include any number of plant-based chemicals. Some of the most common are lemongrass, citronella, peppermint, geraniol, soybeans, and rosemary. Those ingredients can be oils extracted directly from plants or synthetic chemicals that exactly replicate their natural counterparts.
Do they work? These products are not registered with the EPA. Because the agency does not consider the chemicals they contain to pose serious safety hazards, it does not bother to evaluate them. As a result, companies that make botanicals are not required to prove to federal regulators that they actually work. And CR tests have repeatedly found that they don't work well.
They're safe? Yes and no. The chemicals in these products are unlikely to cause you serious harm, although they do contain known allergens, often in much higher concentrations than other natural products. But by using an unregistered botanical repellent, you put yourself at risk for serious mosquito and tick-borne diseases, some of which can be life-threatening.
The Bad About Bug Repellants
Insect bites are annoying and can also transmit disease. On the television show “Consumer 101,” host Jack Rico goes into Consumer Reports labs to find out how CR tests bug repellants to make sure you're getting the most protection.
Article in English.