Do DEET-free 'natural' mosquito sprays work?
Quick answer
Some help briefly, but most fall short. Plant-oil "natural" repellents typically evaporate and lose effect within about 20 minutes, while EPA-registered actives like DEET and picaridin last for hours — DEET alone has 65+ years of safety data. "DEET-free" doesn’t mean safer; it usually means shorter-lasting.
Why it doesn't work
"DEET-free" and "all-natural" repellent sprays sell on two implied claims: that they’re safer than DEET, and that they protect as well. The evidence inverts both for most of the category.
On safety: DEET (N,N-diethyl-meta-toluamide) has been in civilian use since 1957 and is one of the most studied repellents in the world. The EPA’s reregistration review concluded it does not present a health concern to the general population when used as directed. "Natural" does not mean non-toxic — many essential oils are skin irritants or sensitizers, and most are not reviewed by EPA for efficacy because they’re sold as minimum-risk exempt products, meaning no agency has verified that they work.
On efficacy: the deciding variable is complete-protection time — how long until the first bite. Fradin & Day’s controlled NEJM study measured this directly: DEET-based products protected for hours in a dose-dependent way, while most pure plant-oil sprays (citronella, lemongrass, soybean without a fixative) failed within minutes to a small number of minutes. The reason is volatility: the light terpenes that do the repelling evaporate fast, so protection collapses long before the label’s optimism suggests.
There is one important, honest exception. Oil of lemon eucalyptus (OLE) and its refined active PMD are plant-derived and genuinely effective — the CDC lists them alongside DEET, picaridin, and IR3535 as recommended actives, with protection approaching lower-concentration DEET. So the accurate message isn’t "natural is fake," it’s "natural is not automatically safer or effective — choose by the registered active ingredient and its tested duration, not by the word ‘natural’ on the front." DEET, picaridin, IR3535, and OLE/PMD are the four that earn the recommendation; an unspecified "botanical blend" usually does not.
References
- Fradin, M.S. & Day, J.F. (2002), "Comparative efficacy of insect repellents against mosquito bites," NEJM 347:13–18.
- U.S. EPA, "DEET" reregistration / safety review.
- CDC, recommended repellent active ingredients (DEET, picaridin, IR3535, OLE/PMD).link pending verification
What to do instead
The honest answer isn't "give up" — it's to target the host-seeking females directly. A CO₂ + heat trap broadcasts the breath-and-body cues mosquitoes actually follow, drawing them away from you and capturing them, without spraying pesticide across your yard.
See the SkeeterSwitch bundleCommon questions
Are natural mosquito sprays as good as DEET?
Usually not. Most plant-oil sprays evaporate within minutes; DEET protects for hours. The exception is oil of lemon eucalyptus (PMD).
Is DEET safe?
Yes, when used as directed. The EPA found no health concern for the general population, and it has 65+ years of safety data.
Does "natural" mean safer?
No. Many essential oils irritate skin, and minimum-risk "natural" products aren't EPA-reviewed for whether they even work.
Which repellents actually work?
EPA-registered DEET, picaridin, IR3535, and oil of lemon eucalyptus (OLE/PMD). Choose by active ingredient and tested duration.