DEET - The effective mosquito spray

DEET is the most effective mosquito repellent available today. It has been illegal in Denmark since 1996, when the popular mosquito spray Jungle oil was taken off the market.

However, there are currently two mosquito repellents with DEET approved in Denmark: MosquitoFree and Apotekets Insect Spray. They contain 9.5% and 40% DEET respectively, and are probably the most effective mosquito repellents on the Danish market.

You can buy MygFri here and Apotekets Insect Spray here


However, if you are looking for a DEET-free alternative, you have been able to buy an almost equally effective mosquito spray in Denmark since 2003: Active Autan. The advantage of Autan is that it doesn't cause the same health damage as DEET-based mosquito repellents. In addition, it is approved by the Danish Environmental Protection Agency, so you can buy it legally.

Autan mosquito spray is the most effective mosquito repellent without DEET on the Danish market


When should you use DEET mosquito spray?

Our recommendation is to only use DEET mosquito spray when it is absolutely necessary. For example, in Denmark - where there are generally not many mosquitoes - you can almost always use Autanwhich is almost as effective.

Using DEET mosquito spray is recommended if you are traveling to areas where there are mosquitoes, for example:

  • risk of malaria (e.g. in certain parts of Africa)
  • risk of other mosquito-borne diseases (West Nile fever, dengue fever, etc.)
  • extremely high mosquito numbers (e.g. a hot, rainy summer in Sweden)

When using a mosquito repellent based on DEET, the dose of the active ingredient is very small and the damage to the body will therefore be very limited.

However, if you use DEET mosquito spray by default or for an extended period of time, you should strongly consider the alternatives, as the damage can be more extensive in these cases.

DEET is the most effective mosquito repellent in the world, but should only be used when it's really necessary

DEET mosquito repellents should only be used when truly necessary


What is DEET?

DEET is another name for N,N-Diethyl-meta-toluamide or diethyltoluamide. Globally, DEET is the most commonly used ingredient in the group of insecticides that work by deterring insects (repellents). The second most commonly used ingredients in this group of insecticides are essential oils such as citronella oil and eucaluptus oil.

DEET has a slightly yellowish color and is similar in consistency to oil. It is applied to the skin or clothing and effectively protects against mosquitoes and many other biting insects.

DEET was originally developed for military use by the US Department of Agriculture in 1944 and is still used by the military in some countries (e.g. Sweden). The substance was also tested as an agricultural pesticide. It was used as an insecticide and mosquito spray by the US Army in 1946 and by the civilian population in 1957.


The effect of DEET

DEET has a deterrent and damaging effect on mosquitoes and some other insects, while it only has harmful effects on mammals and fish.

The harmful effects on humans have not been proven, but there is a consensus among experts that DEET is harmful to health. In particular, it is suspected that prolonged use of DEET products can cause noticeable damage.

It's worth mentioning that DEET is a solvent that can dissolve plastics, spandex, viscose and other synthetic fabrics. It can also dissolve painted or varnished surfaces (including nail polish).

Below you can read about the effects of DEET on insects and humans.


Impact on insects

It was originally thought that DEET blocked certain receptors in insects, reducing their ability to detect human sweat and breath. In other words, it was believed that DEET inhibited the insects' senses so that their instinct to sting and suck blood was not activated when they came near humans or animals with the active ingredient on their bodies. The experts also believed that DEET had an impact on the insects' ability to detect carbon dioxide from humans.

However, all of these assumptions have been proven wrong. More recent studies has shownDEET acts as a real repellent - meaning that it has a real deterrent effect on mosquitoes and that mosquitoes are even repelled by its odor.

DEET has also been found to affect some sensory mechanisms in mosquito antennae in a similar way to eucalyptol, the active ingredient in eucalyptus, which is also used in mosquito sprays and other mosquito repellents.

In several places, it has also been reported that the mosquitoes' resistance to DEET is increasing.


Impact on humans

Although the amount of DEET in a single dose of mosquito repellent is usually relatively small, you should still be aware that it is very likely to cause some damage to the nervous system. The concentration of DEET in mosquito repellents is typically 10 -30%, but can be 100% in some products.

The exact effects of DEET on human health are still being debated, but the consensus is that DEET:

  • is a neurotoxin for insects and mammals (whether this also applies to humans is unknown - but it is suspected because the nervous systems of animals and humans are similar)
  • Amplifies the effect of carbamates, which can damage the human nervous system (read more below)

Mosquito sprays and other mosquito repellents based on DEET are often mixed with other insecticides to optimize their efficacy. A frequently used group of these are the so-called carbamates. When DEET is used with carbamates, it can amplify their effect. The problem for human health is that carbamates inhibit an enzyme called acetylcholinesterase. In humans, this enzyme is important for the function of the central nervous system.

DEET can also be measured in blood and urine, which can be used to diagnose poisonings and overdoses.

It's worth mentioning that attitudes towards DEET vary greatly globally, with some places banning the substance altogether, while others consider it to be be harmless. Because the manufacturers and distributors of DEET products have a financial interest in not banning the substance, it is also questionable whether lobbying is thwarting research into the harmful effects of DEET on humans (as seen in the tobacco industry, for example).



Autan mosquito spray is the most effective mosquito repellent on the Danish market



The most popular mosquito repellent

Worldwide, DEET is the most commonly used active ingredient in mosquito repellents. This is, of course, because DEET is an extremely effective mosquito repellent. But nowadays, with the availability of other effective mosquito sprays (especially Autan), there's no need to use DEET-containing mosquito repellents - even if you're abroad.

Researchers estimated in 2009that around 200 million people use DEET-based mosquito repellents every year. They also estimated that since the 1950s, more than 8 billion doses of DEET have been used.

In Africa (where malaria is a widespread problem), DEET is not widely used because it is too expensive. Researchers hope to find an equally effective - but cheaper and less harmful - alternative to DEET in the near future.

In 2013, the a group of American researchers the anti-mosquito receptor protein in DEET. The team also found other synthetic substances that are as effective as DEET and have no side effects. All of this has raised hopes that one day highly effective mosquito repellents without side effects can be developed. The big challenge, however, is the price, which is still far too high for these substances to be used in commercial production.



Although the requirements for consumer information on the safe use of DEET products vary greatly from country to country, virtually every DEET manufacturer in the world is subject to a set of rules on how to label their products. Usually, this includes, at a minimum, instructions for use and warning labels.

In practice, the precautions are to not should use DEET agents:

  • on children under 3 years old
  • on the face
  • in places where the skin is very sensitive
  • on damaged skin
  • on skin under clothing (use only on bare skin - i.e. skin areas exposed to mosquitoes)

When you are no longer exposed to mosquitoes - such as when you return home after spending time in nature - you should wash your skin with soap and water to remove the mosquito spray from your body.