Is DEET bad for you? 9 things to know about bug spray

Because many insects are cold-blooded, they’re more active in the summer when they get more energy from warm weather to feed and reproduce faster. For many of us, that brings more bug bites.

That may mean uncomfortable inflamed bumps and – more seriously – the threat of diseases like West Nile Virus (from mosquitoes) and Lyme disease and Rocky Mountain spotted fever (from ticks).

We usually try to repel insects with products containing DEET, a chemical that’s effective but has a strong scent.

“Bug bites are uncomfortable and inconvenient, often causing itching and skin discoloration. But the more worrisome thing is that bugs can carry diseases,” says dermatologist Susan Chon, M.D. “Bug sprays can be a useful tool to protect you as long as you use them correctly.”

Here are nine things Chon wants you to know about using insect repellant on your skin and in your home.

DEET is safe when you use it correctly 

The best-known bug spray ingredient is DEET, a synthetic chemical that repels mosquitoes, ticks, flies and chiggers. It works by creating a barrier on your skin that masks human odors by blocking the bugs’ smell receptors. It’s been used since the 1950s. 

DEET isn’t recommended for children under 2 months old. Pregnant women should also weigh the benefits against the risk of catching an insect-borne diseases where you live.

“It’s been around for decades and is considered quite safe. Honestly, minor irritation is the common risk,” Chon says. “But use it sparingly. Spray it on your exposed skin, especially ankles, lower legs and arms – and don’t spray it on your face. Put it on your hands and pat it on your face and neck, if necessary.”

A higher percentage of DEET means you are protected for longer

Bug sprays sometimes contain different concentrations of DEET. A higher percentage of this ingredient means it’ll protect you for longer. 

“It's sold at a concentration as high as 50%, but the sweet spot is between 20% to 30%, which protects you for an average of five hours,” Chon says. “If you’re camping in the woods, use the increased concentration of 50%, which lasts longer. If you’re going outside for less time, 10% to 20% DEET will work just fine. It lasts for a couple of hours.” 

Picaridin, essential oils and other effective insect repellents 

DEET is generally known as the most effective repellant for mosquitos, flies and ticks, but there are other options that also work. 

Picaridin, another synthetic compound that mimics one found in pepper plants, also blocks bugs from detecting their prey. It’s less oily than DEET. 

“Bug sprays that contain picaridin have been shown to be as effective as DEET,” Chon says. “It achieves the same results in lower concentrations.” 

Looking for a natural option? The Centers for Disease Control and Prevention (CDC) recommends repellants that contain lemon eucalyptus oil. It’s known to be as effective at repelling some types of bugs as well as low-concentration DEET. These products are approved for children ages 3 and up. 

Additionally, the following essential oils have shown short-term effectiveness, but they evaporate quickly, which requires frequent reapplication: 

• Citronella oil 
• Cedarwood oil 
• Peppermint oil 

“They don’t last as long and are probably not quite as effective,” Chon says. “But they’re natural so some people do feel more comfortable using them.” 

The color and style of your clothes can make a difference for protection 

Clothes that cover your arms and legs are often the best protection against bug bites, but the color of your clothes also matters. 

“Dark clothing can attract bugs because it creates contrast – they can see you better,” Chon says. “Tight clothes can also allow them to bite you through the material. Choose loose-fitting and light-colored clothes.” 

How you apply insect repellent matters 

Chon recommends positioning the spray bottle six inches away from your skin and spraying in an even overlapping pattern that covers all of your exposed skin other than your face. To cover your face, spray some on your hands and then pat your face, avoiding getting it in your eyes or nose. You don’t want to inhale the fumes. 

You also can spray some on your clothes for extra protection, she adds. 

Wash your bug spray off when you’re back inside 

Even though bug spray is safe in approved amounts, it’s a good idea to wash it off when you get back indoors. 

“You should wash the bug repellent off when you get home. There are probably other things on your skin like pollen and possibly even ticks that you would want to remove, too,” Chon adds. 

Medicated creams can help with the side effects of bug bites

Bug bites may cause an immune reaction that leads to itching, inflammation and skin discoloration, which can be irritating. 

“I give my patients a prescription-strength topical steroid cream if they tend to have significant reactions to bug or mosquito bites,” Chon says. “You have to put it on several times a day for the first few days, but this helps prevent excessive swelling and itching. It can also help minimize skin discoloration from bites.” 

Some over-the-counter topical medications that may help relieve itching and inflammation include: 

• Hydrocortisone 1% cream or ointment 
• Products containing the following ingredients with soothing properties: 
  • Pramoxine 
  • Menthol
  • Camphor

Keep your bug spray and sunscreen separate 

Avoid products that combine bug spray and sunscreen. “If you’re wondering if combination bug spray and sunscreen is a good idea, the answer is probably no,” Chon says. “Because you’re not going to use them the same way.” 

Sunscreen should be applied liberally all over your exposed skin and reapplied every two hours. Bug spray should be used in a more measured fashion, and you shouldn’t need to apply it more than once per day for routine use. 

“You want to control the amount of bug spray you use. Put it only in areas where you think you need it and not in excessive amounts,” Chon says. 

The best repellants to use may vary by types of insects 

Best mosquito repellent 

Chon recommends picaridin at a concentration of 20% or DEET at a concentration between 20% and 30%. And if you prefer to avoid chemical repellants, frequently applying lemon eucalyptus oil may be as effective. 

Best tick repellent 

“Ticks are tricky. Use a multitiered approach,” Chon says. She recommends a combination of products with DEET or picaridin, as well as having your clothes treated with permethrin. This is a chemical that disrupts insects’ nervous systems. It’s also possible to buy hiking or camping clothes pre-treated with permethrin. 

If you’re in areas known to have high tick populations, wear long sleeves and pants when outdoors and stay in the middle of trails and away from tall grass. When you get back indoors, check your skin for ticks. 

“The diseases that ticks cause are more common right now in the U.S. than the mosquito ones,” Chon adds. 

Best bug spray for ants 

There are no sprays for ants, and most types of ants in the United States are unlikely to bite unless you invade their home territory. 

Chon recommends being careful around gardens and to be aware of where you are standing. You may not realize that you have stepped into an ant mound until you get bit or stung.

What’s the best bug spray to use indoors? 

Insect repellents are not meant to be used indoors. Instead, keep doors and screens closed to avoid bugs getting inside. If an infestation does occur, it’s best treated with pesticides or natural solutions.  

One example of a natural solution is citronella essential oil, which may deter mosquitoes. 

Always follow the instructions on bug spray 

Whatever bug spray you choose, the most important thing is to follow the instructions on the packaging and to speak with your doctor if you have a negative reaction.

“Your dermatologist should be able to advise you if you have any concerns about insect repellants or the effects of bug bites,” Chon says.

Request an appointment at UT MD Anderson online or call 1-877-632-6789.