Although DEET is no longer the only reliable way to fight mosquitoes, it's still a top choice when the insects seem relentless. In two separate professional tests, products with at least 15 percent DEET are among the top performers for repelling mosquitoes and ticks. In addition, several users on retail sites claim that DEET-based mosquito repellents are the only ones that work reliably for them. Health experts say DEET-based insect repellents are safe for adults and children over two months old, but you should still take some precautions to limit your exposure to the chemical, such as washing it off promptly after you come inside.
The mosquito repellant that does best in professional tests is OFF! Deep Woods VIII (Est. $16 for two 6 oz. cans), an aerosol spray with 25 percent DEET. In one study published in the Journal of Insect Science, this spray did better than any other bug repellent at keeping mosquitoes at bay when it was first applied. Only 6 percent of the mosquitoes in the test chamber approached the hand sprayed with OFF! Deep Woods VIII, while 61 percent were drawn to an untreated hand. However, after 4 hours, the product was much less effective, attracting nearly 30 percent of the available mosquitoes (compared to 68 percent for the untreated hand).
This product does even better in a test conducted by ConsumerReports.org – which, unlike most of the site's reviews, is free to view online. That test found that OFF! Deep Woods VIII continued to repel two different species of mosquitoes for a full 8 hours, putting it on a par with the top performer in the test. However, it proved somewhat less effective at repelling deer ticks; its power petered out about 5 hours after application.
Ashley Weatherford of New York Magazine rates OFF! Deep Woods as one of the best bug sprays she tried. She says it kept mosquitoes at bay for "the better part of an outdoor concert," and it doesn't feel sticky or greasy on the skin. The roughly 80 reviews we found for OFF! Deep Woods at Amazon.com are similarly enthusiastic. Users say the product is very effective against mosquitoes, and the aerosol spray is easy to apply. Most users also say its odor isn't too bad, but some say it has an unpleasant chemical smell. (The reviewers at ConsumerReports.org, by contrast, describe it as mild and vaguely floral, while Weatherford calls it "powdery.") Some users also note that it can damage clothing and gear.
Ben's 30% Tick and Insect Repellent (Est. $19 for three 3.4 oz. bottles) performed even better than OFF! in the Consumer Reports test. This 30 percent DEET spray is about as effective against mosquitoes, but much more effective against deer ticks, keeping them off for more than 8 hours straight. Its biggest downside, according to the reviewers, is its strong and persistent odor, which they compare to rubber cement. The testers say the smell lingers 10 minutes after application, as does the oily residue this product leaves on the skin.
Reviewers at Amazon.com and Cabelas.com, however, don't appear to be bothered by the smell of this bug repellent. That may be because they bought the pump spray version of the product, rather than the aerosol tested by ConsumerReports.org. Regardless, most of the 80-plus reviews we found at these sites describe the odor as inoffensive, while only two say it's unpleasant. Users are also impressed with the product's effectiveness against both mosquitoes and ticks. Some note that it also repels other types of pests, such as biting flies, gnats, and even leeches, though not all reviews agree on this point. Users say Ben's protects for 5 to 6 hours at a stretch and doesn't feel greasy on the skin. Some do comment, however, that the pump spray bottle can be tricky to use.
If you're looking for even longer-lasting protection, there's Repel 100 (Est. $10 for 4 oz.). In the Journal of Insect Studies test, this bug spray got off to a less impressive start, attracting 10 percent of the mosquitoes in the test chamber. However, after 4 hours had passed, the percentage had barely budged, with only 14 percent of the mosquitoes approaching the treated hand.
However, Repel 100 contains far more DEET than any other insect repellent – a whopping 98.1 percent. If that seems like overkill, it might be. Past expert testing has found that DEET concentrations higher than 30 percent did little to boost a product's effectiveness, but could increase the risk of serious side effects, such as rashes, disorientation, and seizures. Reviews at Amazon.com and REI.com indicate that the high DEET levels in Repel 100 have other downsides as well. For starters, there are complaints that it damages clothing and eats through plastic. Several reviewers gripe that a bottle of Repel 100 leaked inside their suitcases and ruined everything inside -- even after being wrapped in an additional plastic bag. Many users also object to the product's oily feel and overpowering chemical smell, and some say it gave them a rash.
Be that as it may, user feedback is relatively strong -- 4.3 stars following more than 1,700 reviews at Amazon.com. The simple reason is that Repel 100 works. Users that hate the smell, feel, and what it can do to plastics still often grant it 4 star and even 5 star ratings for its effectiveness -- even while strongly cautioning others to be prudent in using it.