There are several safe mosquito repellents that are as effective as DEET, considered one of the strongest versions on the market. The three most promising alternatives are picaridin, oil of lemon eucalyptus, and soybean oil. Although picaridin is synthetic, studies have shown low potential for toxicity to humans or to the environment. Oil of lemon eucalyptus oil and soybean oil are naturally-derived products that are also considered safe.
DEET stands for N,N-diethyl-m-toluamide and is a registered pesticide. Although it is very effective at repelling mosquitoes, high exposures have been linked to rashes, seizures, and neurological damage in humans. DEET can enter the body through skin absorption, respiration, and through being ingested. The potential health hazards of DEET-based insect repellents have led many to consider safer alternatives.
Oil of lemon eucalyptus is the only plant-based oil to be approved for use as a safe mosquito repellent ingredient by the US Centers for Disease Control (CDC). The substance is derived from the Eucalyptus citriodora tree, which grows in Australia. Although some studies have shown oil of lemon eucalyptus repellents to be as effective as DEET-containing repellents, it needs to be reapplied frequently. Some people dislike its strong odor and it is not recommended for children under three years of age.
Picaridin is an odorless synthetic safe mosquito repellent ingredient that has been proven as effective as DEET in studies against mosquitoes, fleas, ticks, and chiggers. It is also known as KBR 3023 or Bayrepel in Europe, where it has been used for many years. It became available in the United States in 2005 and is recommended by the CDC. Unlike DEET, picaridin does not cause damage to plastics, fabrics, and leathers. Studies have shown a very low risk of toxicity in humans, meaning that it is relatively safe.
Mosquito repellents containing 2% soybean oil have been shown to be as effective as repellents containing 10% DEET. Soybean oil is a safe mosquito repellent for all ages, but some people dislike its smell and feel. There are several insect repellent products on the market containing soybean oil alone or in combination with geranium oil and lemon oil. One study showed soybean effective against mosquitoes for 3.5 hours.
Other substances have been used as a safe mosquito repellent such as citronella, eucalyptus oil, and tea tree oil. Some of these have been shown in studies to be mildly effective. These products should be reapplied often for maximum effectiveness.
No matter what insect repellent is used, certain precautions should be followed to increase safety. Clothing with long sleeves and legs can act as a protective barrier against mosquitoes. Mosquito repellents should not be applied to wounds, cuts, or irritated skin, faces, or hands. Using as little repellent as possible will minimize any risk of exposure to harmful chemicals.