How to Use Insect Repellents Safely

Ticks, mosquitoes, flies that bite and other dangerous insects can be extremely annoying. While bites are a nuisance, they can also unfortunately pose a serious risk and even cause long term health problems. In many parts of the United States, such insects are known to transmit very dangerous diseases. These diseases can easily endanger a person’s health and even cause death. These type of diseases include illnesses such as West Nile and Equine virus as well as St. Louis Encephalitis.

All such diseases can take months and even years to recover from with consequences and complications that may be life-long. A biting fly may also cause a highly painful bite that not only itches but can linger for days. The bite can also swell up, and become dangerously infected and even pose a threat to an infected limb. Ticks are not innocuous either. A tick bite may transmit equally serious diseases such as Lyme disease, West Nile Virus, or Rocky Mountain Spotted Fever.

It is important to always use insect repellents. An insect repellent will protect you from minor bites. The repellent can also be a live saving measure that discourages very dangerous biting insects from even landing on your treated skin or clothing.

west nile, mosquito repellent

West Nile Transmission Cycle – Image via

Why Insect Repellent Use is Vitally Important

Using insect repellent helps greatly reduce a person’s exposure to most mosquito bites as well as their risk of contracting diseases transmitted by mosquitos. These include very dangerous insects that often that have the West Nile virus or other diseases in their systems. The use of this kind of insect repellent lets people play and work outside without greatly worrying about the serious risk of getting a major and even life threatening infection.

The insect repellent will help make sure that you are doing as much as you possibly can to reduce your expose to such dangerous bugs. All family members should use insect repellent when the risk of exposure to such dangerous bugs exists in an area.

When Should You Use Insect Repellent?

Insect repellent should be used when you are going outdoors for any significant length of time. People should use the repellent even if they only expect to go outdoors for a short period of time. Sometimes you may intend to leave the house for only a quick trip but you’ll often find that you leave the house for much longer than expected.

Most of the mosquitoes that can cause West Nile virus usually bite in early morning or early evening hours. If you plan to be outside during these times, it is essential that you pay very close attention to making sure that you are using repellent on all your family members.

Which Mosquito Repellent is Right For You?

There are a great many kinds of insect repellent products currently on the market. The Centers for Disease Control suggests that people pick products that have known active ingredients that work properly. These are ingredients that are registered with the U.S. Environmental Protection Agency (EPA) and officially approved for use as safe repellents. Such products can be applied to people’s clothing as well as their bare skin.

insect repellents

Some of the many insect repellents available on the market today.

When this agency allows registration of a specific repellent, they first take care to evaluate the product in question very carefully for efficacy. They also make sure that the potential effects on people and the environment are safe.

When you see the registration on the label it means that EPA expects that this product, if used exactly and according to the label on it as well as the written instructions posted on the packaging of the repellant, to not have any unreasonable adverse effects that may cause serious or even minor harm to your health or to our environment.

Many active ingredients have been registered with the EPA. However, two in particular have demonstrated a higher degree of efficacy in all studies done so far. Any products that have the following active ingredients usually will provide far longer-lasting protection than other products that are currently on the market:

  • DEET (N,N-diethyl-m-toluamide)
  • Picaridin (KBR 3023)

Another commonly used insect repellent is oil of lemon eucalyptus [p-menthane 3,8-diol (PMD)]. This is a plant based repellent that is registered with EPA. Two recent scientific publications have show that this product can also provide similar protection against insect bites to that found in DEET.

These products are only advised for people living or those temporarily traveling in the United States. If you need information about useful insect repellents in other countries, you can find it on the CDC Travelers’ Health website.

Permethrin is another recommended product that people can use on items such as clothing, bed nets, shoes or camping gear. It has been proven to protect against mosquito bites. This chemical compound is known to be a very effective insecticide as well as an insect repellent. Clothing that has been treated with Permethrin can repel and even kill mosquitoes, ticks and other dangerous bugs.

It will retain this useful effect after it has been through the wash multiple times. The insecticide needs to be reapplied after you carefully follow the exact label instructions. There are some commercial products on the market that have already been pre-treated with Permethrin. Do not use this product directly on your skin or the skin of your pets or children.

How Often Should the Repellent be Applied?

When using any insect repellent, it is vitally important to follow the exact directions that you can read on the product. If you sweat heavily or you find yourself in contact with water in some way, you will need to apply the product more than once.

Know How the Percentage of the Active Ingredient Relates to Its Protection Time

Be aware that as a rule of thumb, products that contain more active ingredients will provide longer protection from mosquitoes. Read the labels carefully and note the percentage of active ingredients in all products that you use.

DEET products are found on the shelves in many formulations. A product that contains 30% DEET will protect someone in general longer than one that only contains 5% DEET. Be aware as well that direct comparisons between active ingredients are not useful.

Always err on the side of caution. Never hesitate to reapply insect repellent if you think you are getting bitten and make sure that you are following the instructions on the label.

Some basic rules include:

If you are planning to spend a great deal of time outside in a given period, (over three to four hours) and/or where you are in an area where you see the biting is extremely intense, you should use a product with a high DEET concentration. Make sure that you have a repellent that contains at least 20% DEET. A product that has more than 50% DEET will not give you any additional protection.

If you are outside for a shorter period, you can use repellents that have less than 20% DEET. You can also use repellents that have 7% picaridin. Another good choice for optimum protection is one of the products that has oil of lemon eucalyptus. Other products on the market are available but they may not work as well or may contain ingredients that have not been studied closely.

Even during a short walk of less than ten minutes, it is important to apply repellent as you can still get bitten. If possible, plan ahead and apply repellent to your clothing for even more protection.

Pick repellents that you can use consistently that provide the ideal protection for the amount of time that you plan to spend outside. A product label will tell you how long you can expect the product to be effective. Address any additional concerns to your health care provider.

The Percentage of DEET and Its Relationship to Protection Time

In general, a product that contains more active ingredients will provide more protection than one that contains less ingredients. Remember that active ingredients cannot be compared. If you have a 10% concentration of one product that will not mean it works the same as a product that contains a 10% concentration of a different product.

DEET is an extremely active ingredient that is found in many repellent products as well as a variety of formulations. Studies have found that a product that has

23.8% DEET was able to provide an average of 5 hours of protection from dangerous mosquito bites. Products that contained 20% DEET were shown to provide nearly 4 hours of protection.

Products with about 6.65% DEET could provide almost 2 hours of protection. A product that contained only 4.75% DEET could still provide about 1 and a half hours of protection against such bites.

The actual protection can vary widely and depends on other factors such as water exposure and temperature. Use a repellent that offers protection for the amount of time that you anticipate being outdoors. Products that have more of an active ingredient are good choices when you will be outdoors for at least several hours. A product that has a lower concentration should be used only if you expect to outside for a short time. Reapply it if you find yourself outside for a longer time.

Other Kinds of Repellents

The CDC has other products that contain active ingredients that have been registered with US Environmental Protection Agency (EPA) that can be used as insect repellents on your clothing or skin.

insect repellent for adults

Only use repellents whose ingredients are EPA approved.

Any EPA-registered active ingredients have repellency but some are known to provide more protection than others. Research reviewed by CDC tells us that repellents that contain DEET (N,N-diethyl-m-toluamide) or Picaridin (KBR 3023) can help provide longer-lasting protection than other products.

Research also shows that Oil of Lemon Eucalyptus (p-menthane-3,8-diol) can offer longer lasting protection against mosquito bites than other plant-based insect repellents.

Permethrin is another repellent that must only be used on your clothing and gear. It should not be applied directly to skin. Be aware that the more active ingredient in a given (higher concentration) repellent, the longer time it will protect you against mosquito bites.

Those who are concerned about using insect repellents should consult their health care provider. The National Pesticide Information Center (NPIC) also has a toll-free number, 1-800-858-7378 or

How to Use DEET on Kids

  • All repellent products must state any age restrictions. If you see none, the EPA has not restricted use to a specific age group.
  • Do not use Oil of Lemon Eucalyptus on kids under three.

There are no definitive studies about using what specific concentrations are safe to use on children. Existing studies have found no evidence of health problems when DEET is used on children.

insect repellents on kids

Make sure to follow all label instructions when applying insect repellent to yourself or your child.

The American Academy of Pediatrics has stated that parents should not use DEET on infants younger than two months. When using DEET on children, take multiple factors in account including the time you expect to be outdoors with the child as well as the number of known mosquitoes in the area. Carefully follow the recommendations on the label.

First apply the repellent to your own hands. Afterwards, rub the repellent on your child. Do not get it in the child’s mouth or ears and be careful when applying it around their ears. Do not use repellent on their hands as they may put their hands in the mouths and accidentally swallow it. Young children should not be allowed to touch the repellent nor apply it themselves.

More Tips

Do not use repellent under your clothing or on open sores or wounds. Avoid contact with your eyes or mouth and do not use a heavy spray. A light coating is effective. When coming back inside, wash all clothing and any skin that has been exposed to a repellent. If you see a rash or other evidence of any kind of reaction, do not use the product again and consult your Doctor for possible allergic reactions to any ingredients in the product.

Always use a product that has been approved by the FDA. Anything else could be highly dangerous. Read all labels carefully. Make sure the product is out of reach of all children in your house. Make sure the product you use protects against the insect hazard you expect to encounter. Never assume a product will protect against mosquitoes if it does not say so on the label.

Can You Combine Sunscreen and Insect Repellent?

If you are out on a very sunny day, you may want to use both a sunscreen and an insect repellent at the same time. This is safe. Apply the sunscreen first, then apply the insect repellent over the sunscreen. Consider wearing long pants and a long sleeved shirt as well as a hat instead of sunscreen if possible. The insect repellent can then be applied to your clothing rather than directly to your skin.

Avoid products that contain both DEET and sunscreen. These products have highly differing uses and instructions. The two products should not be combined in a single substance.

Insect repellents are a highly useful item that everyone should have on hand. Follow the instructions on the label carefully. This way you can easily make sure that all members of your family are protected against dangerous insects and the potentially life threatening diseases they carry.



Centers for Disease Control & Prevention –
Environmental Protection Agency –
National Pesticide Information Center –
American Academy of Pediatrics –