DEET vs picaridin

The short version

Both DEET and picaridin are EPA-registered conventional repellents, and both appear on the CDC's list of actives shown to repel mosquitoes when used as directed. Neither one is a gimmick, and neither one is dangerous when used on the label.

So if you came here expecting "one of these is a scam", that is not the answer. The answer is that they behave differently in your hand, on your clothes and around your kids, and those differences decide the purchase:

• Picaridin is the better default for most people most of the time. No plastic damage, essentially no odor, no greasy film.
• DEET is the one to reach for when the pressure is genuinely severe, because the top-strength formulations are still the heaviest hitters available over the counter.
• Neither active does anything about how many mosquitoes exist in your yard. That is a separate job, and a more valuable one — see how to get rid of mosquitoes in your yard.

What each one actually is

DEET (N,N-diethyl-meta-toluamide) has been in civilian use since the late 1950s and is the most studied insect repellent in existence. The EPA has re-reviewed it repeatedly and continues to register it for use on skin and clothing, including for children, when the label is followed. It is sold from roughly 5% up to around 100%, and the concentration controls how long protection lasts rather than how strongly it repels.

Picaridin (also called icaridin, and sold under the chemical name 2-(2-hydroxyethyl)-1-piperidinecarboxylic acid 1-methylpropyl ester) is newer to the United States, registered here in the early 2000s after wide use in Europe and Australia. It was developed to resemble piperine, a compound found in the plants that give us black pepper, and it is a synthetic molecule rather than a plant extract. US consumer products are typically 10% or 20%.

Both are repellents, not insecticides. They do not kill mosquitoes. They interfere with the insect's ability to lock onto you, which is why they have to be on the skin the mosquito would otherwise land on — a missed patch of ankle is a bitten ankle. What attracts mosquitoes explains what the repellent is competing with: carbon dioxide, body heat, moisture and the odor from skin bacteria.

Head to head

The specs below are the registry listings' own figures and the manufacturers' stated claims. We do not lab-test repellents and we are not going to pretend otherwise.

Two rows in that table do most of the deciding.

Plastics. DEET is a solvent. It will cloud or soften some plastics and can damage certain synthetic fabrics, which in practice means phone cases, watch straps, sunglasses frames, rod handles, binocular bodies, waterproof shells and the plastic parts of a fishing reel or a rifle stock. Picaridin does not do this. If you handle gear while wearing repellent — anglers, hunters, photographers, cyclists, anyone holding a phone — that single row is the whole argument.

Age limits. Picaridin products are used per their own labels, and the broad pediatric guidance in the US is that DEET is not for infants under two months and that oil of lemon eucalyptus is not for children under three years. Those two numbers are the ones parents actually need. Kid-safe mosquito repellents goes through the age restrictions product by product.

Where DEET still wins

We default to picaridin, but there are cases where DEET is the right buy and we are not going to be precious about it:

• Extreme pressure. A marsh at dusk, a Gulf Coast summer, standing water nearby, a tropical trip. High-concentration DEET is the strongest over-the-counter option and it has decades of field use behind it in exactly these conditions.
• Disease risk travel. Where the mosquito matters medically rather than cosmetically, the usual advice is to use what is best established. DEET is the most studied active there is.
• One bottle that covers everything. DEET works on mosquitoes, ticks, biting flies, chiggers and no-see-ums, and the high-strength formats are widely stocked.
• Price and availability. You can buy DEET anywhere, cheaply, in any strength. Picaridin is easier to find now than it was five years ago, but DEET is still the one on the shelf at the gas station.

Two things worth knowing about concentration. First, going above roughly 30-50% DEET buys very little extra duration for most uses — the curve flattens. Second, "100% DEET" exists for extreme expeditions and is overkill for a backyard barbecue, where it will also do the most damage to your sunglasses.

Where picaridin wins

• Gear safety. No crazed phone screen, no tacky watch strap, no ruined rain jacket.
• Feel and smell. It dries light and does not announce itself. This matters more than it sounds, because a repellent you dislike is a repellent you under-apply — and the commonest reason people get bitten while wearing repellent is patchy coverage, not a weak active.
• Long days. A single morning application rated for up to 12 hours suits a day of yard work, a round of golf or a fishing trip better than reapplying something sticky every three hours.
• Families. Used per the label, it is the easy choice for a household that wants one bottle for the adults and the older kids.

Where oil of lemon eucalyptus fits

OLE deserves a place in this comparison because it is the only plant-derived active on the CDC's list. It is not the same thing as lemon eucalyptus essential oil — the registered repellent products contain refined OLE standardized for the active compound PMD, which is why they carry an EPA registration and an essential-oil bottle does not.

What to expect: real protection for a few hours, a strong lemon scent, a light feel, and an age restriction at three years. It is the right answer for someone who specifically wants a plant-based active and is willing to reapply. It is the wrong answer for a long day or for severe pressure.

What it is not is an endorsement of "natural" repellents generally. Citronella candles, wristbands, ultrasonic apps and essential oils dabbed on a wrist do not protect you, and natural mosquito control sets out what in that category actually earns its keep.

The option that beats both: do not put anything on your skin

For the specific case of sitting still in one place — a patio chair, a deck, a camp table, a seat at a cookout — a cartridge repeller that fills a zone with a vaporized repellent does the job with nothing on your skin at all. It is also the only answer that works for people who will simply not apply a lotion.

The trade-offs are honest ones: it needs still air, it takes 15 to 20 minutes to build a zone, it protects a seating area rather than a person, and it does nothing the moment you walk away from it. Thermacell vs bug zapper and mosquito trap vs repellent compare that approach with the devices people usually buy instead.

A reasonable household kit is all three layers: a bottle of picaridin for the people, a zone repeller for the seat, and larval control on the water in the yard.

Applying either one so it actually works

Most "repellent did not work" reports are application problems. The fixes are free:

1. Cover every exposed inch. Ankles, the backs of hands, the gap between sock and cuff, the hairline, the back of the neck, behind the ears. Mosquitoes find the patch you missed.
2. Spray your hands and wipe your face — never spray a face directly, and never a child's hands, which go in mouths and eyes.
3. Apply sunscreen first, repellent second, with a few minutes between them. Avoid two-in-one sunscreen-plus-repellent products: sunscreen needs frequent reapplication and repellent does not.
4. Reapply on the label's schedule, not on the smell. Sweat, swimming and towel-drying all shorten it.
5. Apply to skin, not under clothing. For clothing, the separate product is permethrin, which is treated onto fabric and gear and is never applied to skin. Read its label carefully and keep cats away from treated items until they are fully dry.
6. Wash it off when you come in. Not a safety emergency, just good practice, and it is on most labels.
7. Do not use repellent on broken skin, around eyes or on sunburn.

What neither active will do

A repellent protects the person wearing it for the hours it is on. It does not reduce the mosquito population by one insect. If your evenings are unbearable, the leverage is not in the bottle:

• Tip out standing water weekly. Some species breed in a container the size of a bottle cap in about a week, so plant saucers, clogged gutters, tarps with a sag in them, bird baths, buckets and old tires matter more than any purchase.
• Treat water you cannot drain with BTI, a bacterial larvicide specific to mosquito and fly larvae that the EPA approves and that is harmless to fish, pets and birds. Do mosquito dunks work covers the evidence and the dosing.
• Cut back the damp shade at the edges of the areas you use, because that is where adults rest during the day.
• Run a fan on the patio. Mosquitoes are weak fliers and cannot hold a course in moving air.

Best yard mosquito repellents is the yard-side roundup, and best mosquito traps covers the device category honestly, including the part where a trap thins a population over weeks rather than clearing an evening.

Dogs, cats and the rest of the household

Do not use a human repellent on a pet. DEET is not for dogs or cats, and several essential oils marketed as natural alternatives are worse rather than better — tea tree, pennyroyal, pine, citrus and wintergreen are all poorly tolerated by cats in particular.

The right approach for a household with animals is to repel the people, protect the yard with products whose labels allow pets back on the grass once dry, and talk to a vet about heartworm prevention, which is the actual mosquito-borne risk to a dog. Mosquito repellent for dogs sets that out in full, and pet-safe mosquito yard sprays covers the yard products.

So which should you buy?

• One bottle for a normal summer: 20% picaridin. Long stated duration, no gear damage, no smell, pleasant enough that you will actually reapply it.
• Severe pressure, travel or disease risk: DEET, at 25% or higher.
• You want a plant-based active with a real registration: oil of lemon eucalyptus, reapplied every few hours, not for under-threes.
• You will never put anything on your skin: a cartridge zone repeller for the seat you are sitting in, plus the yard work above.
• A child under two months: no repellent at all. Use a net over the stroller or carrier, long sleeves and avoidance at dusk.

Price brackets rather than numbers, because these products change price constantly and a stale figure is worse than none: picaridin and OLE usually sit in a similar mid bracket, DEET is the cheapest per bottle, and the zone repeller is the biggest up-front spend with an ongoing cartridge cost. Check the current price on each pick before you buy.