It’s a simple question, one that readers ask us every summer: Do natural insect repellents work? 

The answer is a bit tricky. Two of the three active ingredients that earned our recommendation this year (picaridin and oil of lemon eucalyptus, or OLE) are derived from plants. But several other plant-based chemicals (including lemon grass and soybean oil) remain at the very bottom of our ratings list.

Daniel Fabricant, executive director and CEO of the Natural Products Association, a trade group, has defended those low performers by pointing out that there’s variation in the effectiveness of all repellents, natural and synthetic.

But the discrepancy between what works and what doesn’t is less random than that statement suggests. All of our top-rated repellents are registered with the Environmental Protection Agency (EPA), and none of our bottom-rated ones are. An EPA-registration means that the product has been evaluated by federal regulators to ensure safety and effectiveness. The agency requires this verification for some chemicals (like deet, picaridin, and oil of lemon eucalyptus) but not others. 

Here’s a quick breakdown of which compounds are EPA-registered, which aren’t, and what our testing has found

Oil of Lemon Eucalyptus

What is it? It’s important not to confuse this product with lemon eucalyptus oil. The names are very similar, but the two chemicals are quite different. OLE is an oil extracted from the gum eucalyptus tree (native to Australia); the actual extracted chemical is called PMD and has demonstrated efficacy 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. 

Does it work? Yes. At least one OLE-based productRepel Lemon Eucalyptus, 30%, earned our recommendation this season. In our tests it warded off insects for at least 7 hours. 

Is it safe? The EPA classifies PMD as a biopesticide, which means it’s subject to more safety testing than botanicals (see below), including lemon eucalyptus oil, but less testing than synthetic chemicals like deet and picaridin. Both federal regulators and our experts agree that OLE is relatively safe.

But it’s important to use these repellents carefully and as directed, because when misapplied they can cause temporary eye injury. The product hasn’t been well-tested on children, and the Centers for Disease Control and Prevention and Consumer Reports advise against using OLE-based repellents on children younger than 3.

Picaridin

What is it? The picaridin molecule is synthetic, meaning it’s made in a laboratory by chemists. But it was modeled after—and closely resembles—a chemical found naturally in black pepper plants.

Does it work? Research suggests that at concentrations of at least 20 percent, picaridin can provide as much protection from bug bites as deet. Our testing also shows it to be a top performer; several products that earned our recommendation this year contain picaridin. But we also found that concentration matters. One picaridin product, this one just 5 percent, was our second-lowest-scoring insect repellent.

Is it safe? Repellents containing picaridin are EPA-registered and subject to the same level of EPA safety evaluation as deet and other synthetic chemicals. The agency found—and our experts agree—that picaridin is safe, even for use on infants. But use as directed because if misapplied, it can irritate your skin and eyes. 

Botanicals

What are they? Botanical repellents are those most likely to have "natural" on their product labeling. They can include any number of plant-based chemicals. Some common ones are lemon grass, citronella, peppermint, geraniol, soybean, 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 aren’t registered with the EPA. Because the agency doesn’t consider the chemicals they contain to pose any serious safety risks, they don’t bother to evaluate them. As a result, the companies that make these products aren’t required to prove to federal regulators that they actually work. And our testing has repeatedly found that, in fact, they don’t. 

Are they safe?  Yes and no. The chemicals in these products are unlikely to cause you any serious harm themselves, though they do contain known allergens, often at much higher concentrations than other natural products. But by using an unregistered botanical repellent, you expose yourself to the risk of serious mosquito- and tick-borne diseases, some of which can be life-threatening.  

A picture of several types of natural mosquito repellent.
None of these 'natural' insect repellents protected against Aedes mosquitoes for more than one hour.
Guide to Mosquito and Tick Diseases

Where Most Cases Occur
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Serious Side Effects

Symptoms appear

Treatments

Common Symptoms
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