Picaridin and DEET are both on the CDC's list of active ingredients for EPA-registered insect repellents, and a 2018 Journal of Travel Medicine review found little difference between them when applied at the same dosage. DEET has the longer record and comes in higher strengths. Picaridin has little odor. Pick the one you will happily wear all evening.
A repellent only works if it is on your skin, and the evenings worth protecting are the long ones: patio dinners past sunset, the last mile of a trail. Here is the honest picaridin vs DEET breakdown, with the real study numbers, so you can choose and get back outside.
Picaridin vs DEET at a glance
| DEET | Picaridin | |
|---|---|---|
| What it is | Developed by the U.S. Army in 1946 (EPA) | A human-made compound first made in the 1980s, designed to resemble piperine from the black pepper plant family (NPIC) |
| Registered for public use | 1957 (EPA) | EPA registered 2001; in US stores since 2005 (NPIC) |
| Strengths for skin | 5 to 99% (EPA) | Under 30% in current formulations (2018 Journal of Travel Medicine review) |
| How long it lasts | Mosquitoes about 2 to 12 hours, ticks about 2 to 10 hours, depending on the percentage (EPA) | Higher percentages last longer (CDC); little difference from DEET at the same dosage (2018 review) |
| Ticks | On the CDC tick list | On the CDC tick list |
| Plastics and fabrics | Labels warn it can damage some plastics and synthetic fabrics, not cotton, wool or nylon (EPA) | Not covered by our sources |
| Odor | Not covered by our sources | Technical-grade picaridin is a colorless liquid with little odor (NPIC) |
| On the CDC repellent list | Yes | Yes |
What is DEET?
DEET is the long-standing name in repellents. According to the EPA, it was developed by the U.S. Army in 1946 and registered for use by the general public in 1957.
It also comes in the widest range of strengths: the EPA notes that formulations registered for direct application to skin contain from 5 to 99% DEET. If you want a very long stretch of protection from one application, that range gives you higher-strength options.
What is picaridin?
Picaridin (sometimes typed "picardin," as in "picardin vs deet" searches) is the newer of the two. The National Pesticide Information Center (NPIC) describes it as a human-made compound first made in the 1980s, designed to resemble piperine, a natural compound found in the group of plants used to produce black pepper.
The EPA first registered picaridin in 2001, and NPIC notes it has only been available in the United States since 2005. Outside the US you will often see the same ingredient called icaridin, and the CDC lists it as picaridin (KBR 3023). Same active, two names.
On the feel side, NPIC says technical-grade picaridin is a colorless liquid with little odor.
Does picaridin work as well as DEET? What the studies found
The honest answer comes from the studies that put the two side by side. Most guides skip the numbers. Here they are.
| Study | What was tested | What it found |
|---|---|---|
| Journal of Medical Entomology, 2004 (field trial, Northern Territory, Australia) | 19.2% picaridin vs 20% DEET in ethanol vs a 35% DEET gel, on people outdoors. Most mosquitoes caught were Culex annulirostris (57.8%), plus two Anopheles species | Against Culex annulirostris, 19.2% picaridin gave over 95% protection for 5 hours and both DEET products for 7 hours, which is when collections stopped. Against Anopheles, protection was relatively poor for all three: picaridin and the 35% DEET gel gave over 95% protection for only 1 hour, and 20% DEET fell under 95% at 1 hour |
| Journal of Travel Medicine, 2018 (review of published DEET vs picaridin comparisons) | Only eight field studies and three lab studies qualified, most at high risk of bias | Little potential difference between DEET and picaridin applied at the same dosage, with some evidence pointing to longer persistence for picaridin |
| New England Journal of Medicine, 2002 (lab test) | DEET, IR3535, botanical products and wristbands. Picaridin was not tested | Higher concentrations of DEET gave longer-lasting protection. A 23.8% DEET product averaged 301.5 minutes of complete protection, a soybean oil product 94.6 minutes, the IR3535 product 22.9 minutes, other botanicals under 20 minutes, and wristbands gave no protection |
The plain-English takeaway: at similar strengths, the head-to-head evidence shows picaridin and DEET performing in the same range. The 2018 review concluded that where only 30% DEET or lower is available, it is reasonable to offer DEET or picaridin as a first choice. Where DEET products above 50% are available, their longer protection time can make them the first choice.
One correction: the 2002 New England Journal of Medicine study is often quoted as comparing picaridin with DEET. It did not test picaridin at all. What it does show clearly is that with DEET, a higher percentage means longer protection.
A formulator's note: higher percentage means longer, not stronger
Cassidy and I spent two years with a Taiwan-based chemist developing our own spray, and this is the idea we came back to most. The CDC puts it simply: higher percentages of active ingredient provide longer protection. The percentage is mostly a clock, not a strength dial.
That is also why the 2018 review lands where it does. Picaridin's maximum concentration in current formulations is under 30%, which caps its longest stretch. DEET goes much higher, so it can offer longer single applications. For a typical evening outside, you rarely need the top of either range. You need something comfortable enough to put on, and to reapply when the evening runs long.
How long does each one last?
For DEET, the EPA says it repels ticks for about two to ten hours and mosquitoes for about two to twelve hours, depending on the percentage.
For picaridin, the field trial above showed 19.2% picaridin giving over 95% protection against Culex mosquitoes for 5 hours, with the DEET products reaching 7 hours when the test ended. Against Anopheles, all three dropped off after about an hour.
The practical rule is the CDC's: pick a higher percentage for a longer day, a lower one for a short evening, and always use insect repellent as directed. If you are also wearing sunscreen, the CDC says to apply sunscreen first and insect repellent second.
Picaridin vs DEET for ticks
Good news for hikers: you do not have to pick a side. The CDC's tick prevention guidance lists EPA-registered repellents containing DEET, picaridin, IR3535, oil of lemon eucalyptus (OLE), para-menthane-diol (PMD) or 2-undecanone.
The CDC adds a second layer for clothing: products containing 0.5% permethrin, which can be used on boots, clothing and camping gear and stays protective through several washings. That is why picaridin vs permethrin is not really a contest. Permethrin goes on your gear, and the CDC says not to use it directly on skin. Your skin gets the DEET or picaridin. Unsure which product suits your trip? The CDC points to the EPA's repellent search tool.
Is picaridin safer than DEET?
Rather than ranking one as "safer," here is what each regulator has found.
DEET (EPA): after its 1998 review, the EPA concluded that insect repellents containing DEET do not present a health concern. Its 2014 interim registration review stated that the Agency has not identified any risks of concern to human health, non-target species or the environment. The EPA notes a final decision is still waiting on endocrine screening, so the 2014 finding is an interim one.
Picaridin (NPIC): picaridin is not considered a skin irritant and is not a sensitizer, though it can cause slight to moderate eye irritation.
Both are on the CDC's list. The habit is the same for either: read the label and follow it.
Plastics, fabrics and feel
This is where the two differ most day to day. DEET labels warn it can damage some plastics and synthetic fabrics, as well as leather, painted or varnished surfaces and watch crystals. The same labels say it does not damage cotton, wool or nylon. Worth knowing if you hike in a synthetic shirt.
Picaridin's appeal is mostly the feel: little odor, per NPIC, which also notes that picaridin applied to cloth deterred insects from biting through the cloth to the skin.
Where plant-based PMD fits
The CDC's list also includes IR3535, oil of lemon eucalyptus (OLE), para-menthane-diol (PMD) and 2-undecanone. PMD is the one we chose to build on. A 2006 paper in the Journal of the American Mosquito Control Association titled "PMD, a registered botanical mosquito repellent with deet-like efficacy" describes PMD as a compound from the leaves of the lemon-scented gum, a spent product of the distillation. It notes that in April 2005 the CDC added two non-DEET mosquito repellents, including PMD, to its guidance, and the authors' view is that this probably underestimates the value of PMD as a DEET alternative.
Our Bloc Off Mosquito Repellent Spray uses 8% plant-based PMD derived from lemon eucalyptus, with 6+ hours of protection in our lab testing. It is DEET-free, alcohol-free and water-based, with aloe vera and chamomile, in a 4 oz (118 ml) bottle. If you want the full picture of the plant-based options, our complete guide to natural repellents walks through each one.
Which one to pack
Think about the day you are planning, not the ingredient debate.
- A backyard evening or patio dinner. A few hours close to home. Choose a comfortable formula you will actually reapply as the evening stretches on. This is the moment our Bloc Off spray was made for.
- An all-day hike in tick country. Treat boots and clothing with 0.5% permethrin ahead of time, then use DEET or picaridin on skin. Pick a higher percentage for a longer day, and mind synthetic gear if you choose DEET.
- Carry-on travel. Liquids rules shape what you can bring, so check our guide on bringing bug spray on a plane before you pack.
- A tropical trip. Our Thailand bug spray guide covers what to bring and how the CDC's traveler advice applies.
Whatever you choose, the goal is fewer bites cutting the day short, and more time out there enjoying it.
FAQ
Is picaridin safer than DEET?
The EPA's 2014 interim review of DEET identified no risks of concern to human health. NPIC reports picaridin is not a skin irritant or sensitizer but can cause slight to moderate eye irritation. Both are on the CDC's list. Follow the label for either.
Does picaridin work as well as DEET?
At the same dosage, a 2018 Journal of Travel Medicine review found little potential difference between them, with some evidence that picaridin lasts longer. DEET's advantage is that it comes in much higher strengths, while picaridin formulations stay under 30%.
Is DEET or picaridin better for ticks?
Both are on the CDC's tick prevention list. The CDC also recommends 0.5% permethrin on clothing, boots and gear, never directly on skin.
What is picaridin made from?
According to NPIC, it is a human-made compound first made in the 1980s, designed to resemble piperine from the black pepper plant family. Outside the US it is often called icaridin.
Can you use picaridin and DEET together?
Our sources do not cover layering two skin repellents, so we cannot recommend it either way. The CDC's guidance pairs an EPA-registered repellent on skin, used as directed, with 0.5% permethrin on clothing and gear for tick country.
Written by Tanya Lee, Co-Founder, with formulator Cassidy Huang. Sources: CDC mosquito prevention, tick prevention and Thailand traveler guidance; EPA DEET page and Recognition and Management of Pesticide Poisonings, chapter 14; National Pesticide Information Center picaridin general and technical fact sheets; Journal of Medical Entomology (2004); Journal of Travel Medicine (2018); New England Journal of Medicine (2002); Journal of the American Mosquito Control Association (2006).