There are thousands of articles online that talk about the controversial ingredient known as DEET. We have listed a few below so that you can quickly see that using any repellent containing DEET is a potential health risk. So why take the risk?

What is ?

DEET is an insect repellent that is used in products to prevent bites from insects such as mosquitoes, biting flies, fleas and small flying insects. DEET is a colorless liquid that has a faint odor and does not dissolve easily in water. DEET was developed by the U.S. Army in 1946 for protection of soldiers in insect-infested areas.

When products containing DEET get into the eyes, they cause irritation, pain and watery eyes. People that have left DEET products on their skin for extended periods of time have experienced irritation, redness, a rash, and swelling. People that have swallowed products containing DEET have experienced stomach upset, vomiting, and nausea.

When DEET was applied to the skin of volunteers by researchers, they found that a small amount of the DEET was taken into the body through the skin. When DEET and alcohol are applied to the skin, more DEET is taken into the skin compared with DEET alone. Drinking alcohol may also cause more DEET to be absorbed through the skin.

The DEET that is taken in to the body can be found in the blood up to 12 hours after it is applied to the skin.

The American Academy of Pediatrics (AAP) has recommended that DEET not be used on children younger than 2 months of age. The AAP has also recommended that DEET should be applied no more than one time per day for children older than two months, and that products should be used on children that have the lowest DEET concentration available. The AAP has cautioned parents not to use DEET on the hands of children and to avoid applying it to areas around children's eyes and mouths.

The American Academy of Pediatrics (AAP)

For at-a-glance information, the activist group Beyond Pesticides keeps its own list of documented DEET health and environmental effects:

  • Cancer: Not documented
  • Endocrine Disruption: Not documented
  • Reproductive Effects: Not documented
  • Neurotoxicity: Yes
  • Kidney/Liver Damage: Yes
  • Sensitizer/Irritant: Yes
  • Birth/Developmental Defects: Yes
  • Detected in Groundwater: Yes
  • Potential Leacher: Yes
  • Toxic to Birds: Not documented
  • Toxic to Fish/Aquatic Organisms: Not documented
  • Toxic to Bees: Not documented

Duke University pharmacologist Mohamed Abou-Donia, in studies on rats, found that frequent and prolonged DEET exposure led to diffuse brain cell death and behavioral changes, and concluded that humans should stay away from products containing it.

A study conducted in the late 1980s on employees of Everglades National Park looked into the effects of DEET found that a full one-quarter of the subjects studied experienced negative health effects that were attributed to exposure to the chemical. Effects included rashes, skin irritation, numb or burning lips, nausea, headaches, dizziness, and difficulty concentrating.

Canada’s federal health department goes further, stating that no child under six months old should be using DEET, and that those who are six months through 12 years old should avoid products that contain more than 10 percent DEET, though that certainly should make one take note as to how potentially dangerous this substance can be.

Canada’s Federal Health Department

DNA damage. DEET has been tested on animals and on human cells in the laboratory, and it’s been shown to cause damage to DNA. A study out of North Carolina’s Duke University found that the results indicated that “dermal administration of DEET could generate free radical species hence cause DNA oxidative damage in rats.” Pharmacologist Mohamed Abou-Donia of Duke University noted that the researchers found that frequent and prolonged DEET exposure led to diffuse brain cell death and behavioral changes. The experts concluded that humans should stay away from products containing it.

Negative impact on the nervous system. A 2008 study out of the Institute of Development Research in France, published in the journal BMC Biology, discovered that DEET can interfere with the activity of enzymes that are crucial in order for the nervous system to function like it should. The researchers found that DEET blocked the enzyme cholinesterase, which is required for transmitting messages from the brain to the muscles in insects. They noted that DEET may also affect the nervous systems of mammals and that more research was needed, but it certainly causes for concern. The study also showed that chemicals that interfere with the action of cholinesterase can cause excessive salivation and eye-watering in low doses, followed by muscle spasms and ultimately death.

Psychological effects have also been reported to the Agency for Toxic Substances and Disease Registry including altered mental state, auditory hallucinations, and severe agitation. Heavy exposure to DEET has also been linked to:

  • Muscle and joint pain
  • Weakness
  • Fatigue
  • Tremors
  • Headache
  • Memory loss
  • Shortness of breath
  • Burning lips
  • Temporary numbness
  • Disorientation
  • Dizziness
  • Difficulty concentrating
  • Nausea
  • Hallucinations

These symptoms are sometimes not evident until months or even years after exposure.

Agency for Toxic Substances and Disease Registry

Workers at a national park who used insect repellents or lotions containing DEET repeatedly during the summer season complained more often of chest pain or wheezing, muscle cramping, skin rashes and blisters, dizziness, disorientation, and difficulty concentrating than workers who used the products less often or did not use them at all.

The researchers showed that DEET does not simply modify the behaviour of insects, but also directly inhibits enzyme activity, both in insect and mammal nerves.

EPA requires that child safety claims be removed from all end-use product labels, as they are misleading and irreconcilable with the intended use and pesticidal ingredients of DEET products, and that all DEET labels inform users to take the following precautions:

■ Do not allow young children to apply this product;

■ Do not apply near children’s hands or face;

■ Apply only enough to cover exposed skin and/or clothing;

■ Do not apply over cuts, wounds and irritated skin;

■ Thoroughly wash all treated skin with soap and water after returning indoors;

■ Wash treated clothes before wearing again; and,

■ Do not spray aerosol forms inside. (EPA, 1998)

Don’t DEET That Dog!

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