DEET is relatively harmless, contrary to popular belief

• DEET is a chemical that is used in most bug sprays.
• It repels insects by producing a smell that drives bugs away and makes your skin taste bad to critters.
• DEET is not toxic to humans when used properly.
• This article was scientifically reviewed by Josh Bloom, who holds a Ph.D. in chemistry. He is now the director of chemical and pharmaceutical sciences at the American Council on Science and Health in New York.
• Visit Insider's Health Reference library for more advice.

Many bug repellents contain N,N-diethyl-meta-toluamide (DEET), a chemical that many people worry can cause serious illnesses like cancer. But research shows that DEET is safe when used properly.

Here's what you need to know about how DEET works and the ways it affects your body.

What is DEET?

DEET is the active ingredient in most bug sprays. It repels mosquitos by hindering their ability to smell humans.

Mosquitoes use their sense of smell to detect the carbon dioxide in your breath and the bacteria on your skin. DEET is able to interrupt this process by producing a smell that drives insects away. And if a bug does land on you, DEET makes your skin taste bad, too.

Insect repellents with DEET often come as aerosol sprays but the chemical can also be found in products like lotion or wristbands. These products can have a wide range of DEET concentrations, ranging from 4% to 100%.

Products with higher DEET concentrations don't necessarily work better to repel mosquitos but are designed to last longer. According to one manufacturer, 7% DEET sprays last for up to two hours, while 98% DEET sprays protect you for ten hours.

The health effects of DEET

DEET is considered to be a safe insect repellent, according to the Centers for Disease Control and Prevention (CDC) and the Environmental Protection Agency (EPA).

Many people worry that it could be harmful to health, possibly because it is a synthetic chemical, but research shows that these worries are unfounded.

"DEET has been around for over 50 years and it has very low toxicity to humans," says Stacy Rodriguez, MS, a laboratory manager at the Molecular Vector Physiology Lab at New Mexico State University.

Here is what we know about the safety of DEET:

• The only study linking DEET to cancer was a small 1998 study from Sweden, which found that people using DEET regularly were more likely to develop testicular cancer. However, the CDC later announced that that the results weren't valid because of flaws in the study's methods. There has been no other evidence that DEET can cause cancer.
• Deet will not build up in your system. When you put on DEET-based bug spray, some of it will be absorbed through your skin and into your bloodstream. It is then broken down by your liver and should leave your body through urine within 24 hours.
• The EPA last reviewed the safety of DEET in 2014 and concluded that, while they recommend that people use it, they will not issue a final decision on its safety until there is an assessment of how DEET affects the body's hormone systems.
• The American Academy of Pediatrics says that DEET should not be used on babies under two months old.
• For pregnant women, there are no reports of health problems, but there have been very few specific studies focused on pregnancy.
• If you use sprays with high concentrations of DEET, over 50 percent potency, you may be at greater risk for skin rashes or irritation.

How to use DEET safely

Safety tips for using DEET:

• Hold the bottle 6 to 8 inches away from you.
• Do not spray directly at your face. Put some in the palm of your hand and rub it in.
• Always use outdoors.
• Do not inhale it.
• Wash your skin with soap and water after you are back indoors.

"DEET is very safe when used properly," Rodriguez says.

For everyday needs, you can use 10% or 20% DEET to avoid mosquito bites. "Higher concentrations of DEET such as DEET 100% are only necessary in places with high mosquito density and risk for mosquito-borne illness," Rodriguez says.

DEET is toxic if it is swallowed, so it is important to put on bug spray for young children and avoid putting it on their hands, as this may lead to getting the spray in their mouths.

If you do swallow DEET, you may experience nausea or vomiting. There have been rare cases where people had seizures after using DEET, but this only happened when people drank DEET products.

DEET is an effective bug repellent that has been used safely for many years, and there is currently no evidence that it causes cancer. Though it is generally safe, you need to take precautions when using DEET to make sure it doesn't irritate your skin or get swallowed.

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