The most effective substances you can put on your skin to repel mosquitoes are EPA-registered active ingredients: DEET, picaridin, IR3535, oil of lemon eucalyptus (OLE), and a handful of others. These work by interfering with a mosquito’s ability to smell and taste you, essentially scrambling the signals that draw them to your skin in the first place. Which one you choose depends on how long you need protection, where you’re headed, and your personal preferences around texture and scent.
How Skin-Applied Repellents Actually Work
Mosquitoes find you primarily through your scent. They track the carbon dioxide you exhale, the lactic acid on your skin, and other chemical signatures your body produces. Repellents like DEET don’t kill mosquitoes. Instead, they activate the same taste receptor that bitter, unpleasant compounds trigger, causing the insect to become confused and fly away. USDA researchers found that DEET interacts with both smell and taste receptors in mosquitoes, which is part of why it’s been so effective for decades.
DEET: The Gold Standard
DEET has been around since the 1950s and remains the most widely available option, with over 500 registered products on the market. It works against virtually every mosquito species and is the benchmark other repellents are measured against.
Higher concentrations provide longer protection, not stronger protection. A product with less than 10% DEET typically lasts only 1 to 2 hours. Concentrations around 20 to 30% cover most people for several hours of outdoor activity. The CDC notes that efficacy peaks at roughly 50% concentration, and anything above that doesn’t add meaningful extra time. So a 100% DEET product isn’t twice as good as a 50% one.
The downsides are familiar to most people: DEET has a strong chemical smell, feels oily on the skin, and can damage plastics, synthetic fabrics, and watch crystals. If you’ve avoided repellent in the past because of that greasy feeling, the alternatives below may suit you better.
Picaridin: Odorless and Fabric-Safe
Picaridin offers protection comparable to DEET without the greasy texture or strong odor. It won’t damage clothing, gear, or sunglasses, which makes it a popular choice for travelers and hikers. About 40 products contain it.
Protection time scales with concentration, just like DEET. A 5% picaridin product protects against mosquitoes for roughly 3 to 4 hours. A 20% product extends that to 8 to 12 hours, making it a solid pick for all-day outdoor exposure. If you want long-lasting, comfortable protection and don’t mind spending a little more than you would on basic DEET spray, picaridin at 20% is one of the best options available.
IR3535: A Lesser-Known Synthetic Option
IR3535 was originally marketed in the U.S. as a skin moisturizer before researchers noticed it repelled biting insects effectively. At 20% concentration, it protects against common mosquito species (Aedes and Culex) for 7 to 10 hours.
It has one notable limitation: protection drops to under 4 hours against Anopheles mosquitoes, the species that transmits malaria. If you’re traveling to a malaria-endemic region in sub-Saharan Africa or Southeast Asia, DEET or picaridin is a better choice. For backyard barbecues and domestic travel, IR3535 performs well and tends to feel lighter on the skin than DEET.
Oil of Lemon Eucalyptus
Oil of lemon eucalyptus (OLE) is the most effective plant-derived repellent with EPA registration. Its active compound, PMD, is refined from the lemon eucalyptus tree and provides real, measurable protection. In standardized testing, a product like Repel Lemon Eucalyptus provided about 2 hours of protection per application.
That shorter window means you’ll need to reapply more often than you would with DEET or picaridin. OLE is a good fit if you prefer a plant-based product and don’t mind carrying it with you for touch-ups. One important restriction: OLE should not be used on children under 3 years old.
Essential Oils: Limited but Not Useless
Citronella, clove, peppermint, and eucalyptus oils do repel mosquitoes to some degree. Research confirms they all provide more than 30 minutes of protection, and clove oil performs better than most essential oils, particularly when formulated with ingredients that slow its evaporation from the skin.
The core problem is duration. In comparative studies, every essential oil tested wore off significantly faster than DEET. Citronella candles and bracelets are even less reliable because the active compounds disperse quickly into the air rather than staying concentrated near your skin. If you’re sitting on a porch for 20 minutes, a citronella-based lotion might be enough. For a hike, a soccer game, or an evening outdoors, you’ll get better results from a registered active ingredient.
A few other plant-based ingredients hold EPA registration: catnip oil (4 products) and oil of citronella (3 registered products). These sit between pure essential oils and the stronger synthetic options in terms of protection time.
How to Apply Repellent Properly
Apply repellent only to exposed skin and the outside of clothing. Spraying it under your shirt or on skin covered by sleeves doesn’t help. If you’re also wearing sunscreen, put the sunscreen on first, let it absorb, and then apply repellent on top. Combination sunscreen-repellent products are generally not ideal because sunscreen needs reapplication every two hours, while many repellents last longer. Reapplying a combo product on the sunscreen schedule means you’re layering on more repellent than necessary.
Avoid spraying repellent near your eyes or mouth. For your face, spray it onto your hands first and then rub it on. When you come back indoors, wash treated skin with soap and water.
Safety for Children and Pregnancy
For infants under 2 months old, repellents should not be applied to the skin at all. Use mosquito netting over strollers and carriers instead. For children older than 2 months, DEET and picaridin are both considered safe when applied by an adult. Oil of lemon eucalyptus is the one exception: it’s not recommended for children under 3.
During pregnancy, DEET is the most studied option. Animal studies using doses far higher than typical human exposure showed no increased risk of birth defects, and a human study covering the second and third trimesters confirmed no adverse outcomes for the baby. No first-trimester studies have been published, but major health organizations still recommend EPA-registered repellents for pregnant women because the risk of mosquito-borne illness (Zika, West Nile, dengue) outweighs the low risk from topical repellent use.
Quick Comparison of Your Main Options
- DEET (20 to 30%): Several hours of protection, widely available, can damage synthetics and plastics
- Picaridin (20%): 8 to 12 hours, no odor, safe on gear and clothing
- IR3535 (20%): 7 to 10 hours against common species, lighter feel, not ideal for malaria zones
- Oil of Lemon Eucalyptus: About 2 hours per application, plant-derived, not for kids under 3
- Essential oils (citronella, clove): Under an hour in most cases, frequent reapplication needed