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Is DEET an Effective Tick Repellent?

deet side effects efficacyDEET is an active ingredient in most mosquito repellents, but is, unfortunately, not particularly effective at keeping ticks at bay. Permethrin is much more effective at keeping ticks under control but there are concerns over the possible connection between the product and Gulf War Syndrome. The efficacy of permethrin compared to DEET was studied by The Minnesota Insect-Borne Disease Education Council as part of field research. Duranon (a 0.5% permethrin solution) outperformed DEET in spectacular fashion as those ticks coming into contact with a shoe sprayed with Duranon three weeks earlier curled up and fell off the shoe whereas ticks continued to walk around unimpeded on a shoe recently sprayed with 35% DEET. DEET is, however, an effective fish repellent, which can explain why some river-fishermen have a hard time catching their supper if using the insect repellent over permethrin which seems to have little effect on fish.

Permethrin – Effective Against Ticks?

Unlike DEET, which is applied to the skin, permethrin is an insecticide applied to clothes and a single application may provide protection against ticks carrying Lyme disease for several weeks if not washed off. The chemical is derived from constituents of chrysanthemum plants and is odorless once applied to clothing and left to air-dry. Those spending considerable time outdoors are often advised to have a separate set of clothing treated with permethrin and sealed in an air-tight container to ensure quick protection is available. Permethrin is toxic to ticks and treating the cuffs, sleeves, waistband, and edges of clothing can cause any ticks intent on biting a human host to curl up and fall off, later dying if exposed to sufficient permethrin.

Availability of Tick-Repellents

Considering the widespread use of both DEET and permethrin, it is surprising that little has been done in the way of research into their safe use over long periods of time. As Lyme disease becomes more of a problem in the US, or at least more widely recognized as an issue, more people are likely to use these chemicals to protect themselves from tick bites. Permethrin products available in the US include Duranon, Permanone, and Congo Creek Tick Spray. In comparison to the ubiquity of DEET-containing products, permethrin sprays are actually quite difficult to come by. Some pet stores carry permethrin at 0.5% for veterinary use as a tick repellent for horses and these pet-products are often cheaper than their human equivalents.

The safe use of such products is also not well known and some people may assume that permethrin can, like DEET, be applied to the skin and reapplied regularly. However, unlike DEET which works as it evaporates, permethrin does not need regular reapplication and should only be sprayed onto clothing. Permethrin is odorless after it has dried, unlike DEET, and has no damaging effects on clothing (DEET can melt synthetic fabrics such as nylon).

Continue Reading –> Alternatives to DEET and Permethrin


Sudakin DL, Trevathan WR, DEET: A Review and Update of Safety and Risk in the General Population. J Toxicol Clin Toxicol, 2003, Vol. 41, No. 6 , Pages 831-839

Osimitz, T.G., Murphy, J.V., Neurological Effects Associated with Use of the Insect Repellent N, N-Diethyl-m-toluamide (DEET), 1997, Vol. 35, No. 5 , Pages 435-441.