To learn more about the specifics of mosquito repellency, we spoke to Laurence Zwiebel, a professor of biological science and pharmacology at Vanderbilt University.Through that process I’ve spent at least 300 hours analyzing products, testing bug gear, reading dense studies on repellent and pesticide efficacy, and interviewing academics, manufacturers, and scientists at the EPA.The tests give you a clear understanding of the repellent, as well as an underlying assurance that it’s safe for use on adults, children, or animals.As Zwiebel told us, “I am very concerned about the lack of regulatory oversight and the ability to disinform or in some cases completely misinform consumers.“People think they are being protected from biting insects and ticks with these products and they are not protected.” —Leslie Vosshall, professor of neurobiology at The Rockefeller University.The agency requires that manufacturers list the ingredients and their concentration levels, that there be no misleading statements on the bottle, and that the repellent “may not bear claims to control rodent, insect or microbial pests in a way that links the pests with any specific disease.” In other words, an essential-oils label can say that the substance repels mosquitoes and ticks, but they can’t say it will protect you from Lyme, Zika, or any other vector-borne disease.One thing very few essential-oil labels indicate is how long the repellency will last—a crucial piece of information if your goal is to protect yourself from disease-ridden insects.These oils aren’t classified as pesticides, so they don’t merit testing under the EPA’s protocols, which are the single standard that judges repellency against disease vectors.In the meantime, we can only go on the science available, and that research leads most experts to dismiss oils as unsafe bug repellents for the same reason we discourage people from using them: uncertainty.Vosshall explained, “People think they are being protected from biting insects and ticks with these products and they are not protected.” She continued, “If these people are in areas where ticks are spreading Lyme and other related pathogens and mosquitoes are spreading Zika, malaria, dengue, yellow fever, west nile, and chikungunya they have the potential to be bitten and infected.” She told us that under no circumstances would she ever recommend an essential-oil repellent.An article in The New England Journal of Medicine, in a similar conclusion, notes, “Alternative ‘natural’ products generally fail to live up to their reputations for greater safety and effectiveness and offer their users a false sense of security.” Last, the Centers for Disease Control and Prevention recommends picaridin, DEET, or another EPA-regulated repellent.Even if essential oils were subject to the EPA’s efficacy-testing guidelines, all indications are that they would fall short of repellents containing picaridin and DEET.Another study, this one published in BioMed Research International, states that “insect repellents with citronella oil as the major component need to be reapplied every 20–60 minutes.”.Repellents such as picaridin and DEET, on the other hand, block a much wider number of receptors on a more consistent basis, as research like Vosshall’s confirms.As Zwiebel put it, “you end up smelling like a rotten fruit basket.” We much prefer the nearly odorless picaridin formulas that we’ve tested.Instead, you can find vague references to “outdoor protection” and “environmental annoyances.” There is no indication of how much to apply, how often, or even if the substance is a repellent at all (we’ve reached out to DoTerra for comment).Customer reviews tell a different story: Nearly all of them describe its efficacy against mosquitoes and other insects, and at least one says, “I would recommend this to anyone looking for a DEET alternative.”.The Amazon page for Mexitan’s Skedattle All Natural Anti-Bug Spray states that the formula is “16 TIMES AS EFFECTIVE as DEET bug repellents.” What does that even mean?No lie!” This is an alluring statement, but our research turned up only one study (PDF) making a similar claim—and, when put in context, it paints a very different picture
