Tick bites are on the rise, and so are the health issues they can cause.
In April all but one region in the U.S. saw the highest level of tick-related emergency room visits since 2017, according to the Centers for Disease Control and Prevention.
Blacklegged ticks can cause Lyme disease, leaving some individuals with lingering brain fog, long-term fatigue, anxiety and depression. Lone star tick bites can lead to alpha-gal syndrome, a lifelong allergy to meat and sometimes dairy products or medicines.
Avoiding getting bitten while you’re outdoors this summer is critical – EWG is here to help you find bug sprays that can maximize safety and effectiveness, while also providing you with important details about ingredients in these products and any health concerns.
Study labels for active ingredients
EWG’s guide to bug repellents suggests three active ingredients as the most effective for keeping ticks (and other insects) at bay.
The guide also gives the safest and most effective concentration levels for different tick and bug repellents, measured as the percentage of active ingredient for different repellents.
DEET (under 30% concentration)
DEET acts as a sensory disruptor for mosquitoes and ticks, repelling both smell and taste receptors. When applied correctly, it has very little health risk. In a 2014 review, the Environmental Protection Agency found that DEET was associated with only low health risks, including to children.
In rare cases, DEET may irritate the skin, usually with highly concentrated formulas – above 75% – and repeated application.
IR3535 (20% concentration)
IR3535 acts much like DEET, repelling insects through its odor. A 2008 study found that 20% IR3535 can offer effective protection against ticks for up to 12.2 hours and mosquitoes for up to 10.3 hours. When used according to label directions, IR3535 has a low risk of causing harmful health effects.
Picaridin (20% concentration)
Picaridin also mimics the effects of DEET, and most evidence suggests it lasts for a similar amount of time – although a Consumer Reports study found it had a slightly shorter window of effectiveness. Like the other ingredients, it’s also relatively safe when used as instructed.
The best of these three ingredients is the one in a product that you’re most likely to use. One study found concentrations exceeding 20% of DEET, IR3535 or picaridin repelled more than 90% of ticks from crossing treated bands on volunteers over a 12-hour period.
If you’re looking for alternatives, oil of lemon eucalyptus at 30% to 40% concentration and 2-undecanone at about 7% concentration have also been shown to be effective – but for less time than the other options.
Apply according to directions
While the risks of any of these chemicals are low in comparison to the risk of tick-borne or mosquito-borne illness, as with any chemical, how you are exposed matters.
With DEET especially, there is some risk of irritation from incorrect use – for example, applying it under clothing, on the face or broken skin, in enclosed areas, or near or on food. Swallowing or overapplying might lead to excessive absorption, which can occur in rare cases and cause harm to the nervous system.
Avoid using any of these repellent chemicals on children under 6 months old.
Apply to clothing
Applying the insecticide permethrin (at 0.5 concentration) to clothing, along with the use of bug spray on your skin, can effectively reduce the number of tick bites. Some outdoor retailers even sell clothing pre-treated with permethrin.
Permethrin can easily incapacitate ticks that land on the clothing and even kill young ticks within a minute of exposure. But there is some human health risk: While exposure is unlikely to cause any significant acute or chronic symptoms, it is highly toxic to the environment. The EPA classifies it as a likely carcinogen when ingested.
When wearing synthetic clothing, including spandex, or other plastic accessories, like sunglasses, avoid applying DEET or IR3535 to areas near the clothing. Because of their solvent properties, both chemicals can dissolve, stain or permanently cloud certain plastics. Picaridin does not damage plastic.
Wear light-colored clothing
If you plan to spend time outdoors, keep in mind that wearing light-colored clothing makes ticks much easier to spot and remove.
Check daily
Bug spray is never 100% effective at repelling ticks. If you’re in a tick-friendly area, checking daily for ticks is one of the best ways to avoid tick bites.
Ticks usually need to stay attached for a day or two to transmit Lyme disease, and despite their small size, they are usually both visible and detectable by touch.
