Mosquito Repellent spray - SAFE or NOT !

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Mosquitoes are one of the oldest enemy of human sleep. We have fought hard against these enemies with different instruments but we are still facing this challenge, as if the supreme power has decided to keep us together till eternity. Human ancestors might have been less affected by mosquitoes due to more hair on the skin, but as we lost extra hair during evolution we invented some techniques such as smoke, skin ointments, coils, mats, liquid vaporizers and mosquito nets. Latest invention to fight against mosquito is Mosquito Repellent Sprays. Advertisements of these products tell us that they are safe, but some scientific studies totally dismiss such claims. We will try to find if Mosquito Repellent Sprays are safe or not.

Before we proceed further you must know that some people become so mush obsessed and overprotective against mosquito that they overuse some products or combine multiple solutions. While doing so they think that they are showing some kind of smartness but such things actually backfire on them. 

According to V. P. Sharma (Malaria Research Centre, New Delhi), 11.8% users of repellents complained of side effects and some required medical attention. However in most of the cases symptoms disappeared after discontinuing the usage. But those who use the repellents for extended periods without any side effect may suffer from neurotoxic and immunotoxic hazards.

According to Dr Sandeep Salvi, Director of Chest Research Foundation, one mosquito coil is equivalent to those of 100 cigarettes.

Mosquito repellent products (coil, spray or cream) are often sold with a printed warning such as "Poison" or "Keep out-of-reach of children", but most of us ignore these warnings.

Now we will tell you about some common ingredients of mosquito repellents and their effect on health.


Most of the mosquito repellent sprays contain DEET. DEET is a chemical compound, originally developed during Worldwar-II to save american soldiers in jungle warfare. It was available for civilian use after 1957. Original liquid was made of 75% DEET and ethanol. DEET reduces the sweat-smelling ability of mosquitoes. Some resent studies have shown that it does not affect the CO2 smelling ability, hence it is not a guaranteed protection. Further the effect of DEET difference from one variety of mosquito to another. At present times 10% concentration of DEET is considered safe for kids (2 to 12 years of age), and 30% for adults.

DEET and sunscreen should not be used together as it enhances the skin penetration capability of DEET. At least 30 minute gap should be made in their application.

Most of the users don't even bother to check the amount of DEET in a mosquito repellent spray before putting it in the shopping cart. We just check that for how many hours it will protect, while the truth is that the longer that duration is - the more percentage DEET it will have. 

DEET is linked to medical conditions like severe epidermal reactions, breathing difficulty, burning eyes and headaches. In 1998 United States EPA reported 14 to 46 cases of potential DEET-associated seizures, including four deaths. In 2002 Health Canada barred the sale of those insect repellents that contain more than 30% DEET. If we take a look at the environmental factors then DEET is slightly toxic to some fresh water fishes, moderately toxic to aquatic animals and very toxic to algae colonies.


This is another most common category of chemicals usually found in mosquito repellents. This category contains more than 1000 different insecticides. This chemical likes to attach itself to fat cells in human body. Most hazardous property of pyrethroids is that it can easily cross the blood-brain barrier and affects our central nervous system. According to WHO, synthetic pyrethroids are neuropoisons. Some of the adverse reactions of pyrethroids on humans are asthma-like reactions, nausea, and burning and itching sensations. Most severe poisoning due to these chemicals occur in infants. It is known to disrupt endocrine function and also a possible carcinogen. 

Some of the most common Pyrethroids are:

  • dl-trans allethrin
  • dl-allethrolone, d-trans chrysanthemate
  • Lambda-cyhalothrin
  • Metofluthrin
  • Tetramethrin
  • Prallethrin
  • Phenothrin
Note : Natural pyrethroids, which are extracted from some flowers are not toxic to humans, but those prepared in laboratories for commercial use are usually not a safer bet. Most of the above mentioned adverse effects belong to artificial pyrethroids. 
Pyrethroids are very toxic to cats. So cat owners should never use it.


This chemical is similar to DDT and accumulates in fatty tissues. It interferes with sodium and potassium ion channels in the nerves and may cause neurotoxicity, loss of coordination, muscle trembling and behavior changes.


It is a synthetic pesticide mainly developed for crops. In human body it may act on sodium ion channels, causing repeated nerve impulses and thus neurotoxicity. It may also result in seizures. If Permethrin and DEET are used in combination then it may cause death of some nerve cells thus causing problems with motor skills, memory problems and physiological/behavioral issues.

As you can see that all of the above chemicals which are found in mosquito repellents have got some serious side effects. We are not asking you to totally avoid using them, but to follow the safety guidelines and read the ingredients of the product before using it. Precautionary measures are more necessary if you have got an infant or a pet in your home. Mosquito repellents should not be sprayed in more quantities and proper ventilation should be allowed if you are using them in a room. 

Stay Safe, Stay Healthy.

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