DEET? We don need no steenkin DEET....

[El Graduado]

Not necessarily true depending on your definition of work.

For me, I only need it when I am outside for a few hours. I find a low dose DEET formula give me around four hours of solid protection. If need more than four hours, I re-apply. In the heat of Cozumel's mosquito season, you probably need to re-apply your repellent at least that often anyway, no matter what the concentration, due to perspiration.

The CDC says:

"CDC recommends using products with ≥20% DEET on exposed skin to reduce biting by ticks that may spread disease."

The New England Journal of Medicine had an article that said:

"The formulation containing 4.75 percent DEET provided an average of 88.4 minutes of complete protection; the formulation containing 23.8 percent DEET protected for an average of 301.5 minutes. There was a statistically significant difference in complete-protection time between each DEET-based repellent and the product with the next higher concentration of DEET (P<0.001 for all comparisons). The controlled-release formulation we tested did not prolong the duration of action of DEET. The alcohol-based product containing 23.8 percent DEET protected significantly longer than the controlled-release formulation containing 20 percent DEET.

Despite the substantial attention paid by the lay press every year to the safety of DEET, this repellent has been subjected to more scientific and toxicologic scrutiny than any other repellent substance. The extensive accumulated toxicological data on DEET have been reviewed elsewhere. DEET has a remarkable safety profile after 40 years of use and nearly 8 billion human applications. Fewer than 50 cases of serious toxic effects have been documented in the medical literature since 1960, and three quarters of them resolved without sequelae. Many of these cases of toxic effects involved long-term, heavy, frequent, or whole-body application of DEET. No correlation has been found between the concentration of DEET used and the risk of toxic effects. As part of the Reregistration Eligibility Decision on DEET, released in 1998, the Environmental Protection Agency reviewed the accumulated data on the toxicity of DEET and concluded that 'normal use of DEET does not present a health concern to the general U.S. population.' When applied with common sense, DEET-based repellents can be expected to provide a safe as well as a long-lasting repellent effect. Until a better repellent becomes available, DEET-based repellents remain the gold standard of protection under circumstances in which it is crucial to be protected against arthropod bites that might transmit disease."

You can read the whole article here:

http://www.nejm.org/doi/full/10.1056/NEJMoa011699#t=articleResults

 

[JohnnyC]

For me, I only need it when I am outside for a few hours. I find a low dose DEET formula give me around four hours of solid protection. If need more than four hours, I re-apply. In the heat of Cozumel's mosquito season, you probably need to re-apply your repellent at least that often anyway, no matter what the concentration, due to perspiration.

The CDC says:

"CDC recommends using products with &#8805;20% DEET on exposed skin to reduce biting by ticks that may spread disease."

The New England Journal of Medicine had an article that said:

"The formulation containing 4.75 percent DEET provided an average of 88.4 minutes of complete protection; the formulation containing 23.8 percent DEET protected for an average of 301.5 minutes. There was a statistically significant difference in complete-protection time between each DEET-based repellent and the product with the next higher concentration of DEET (P<0.001 for all comparisons). The controlled-release formulation we tested did not prolong the duration of action of DEET. The alcohol-based product containing 23.8 percent DEET protected significantly longer than the controlled-release formulation containing 20 percent DEET.

Despite the substantial attention paid by the lay press every year to the safety of DEET, this repellent has been subjected to more scientific and toxicologic scrutiny than any other repellent substance. The extensive accumulated toxicological data on DEET have been reviewed elsewhere. DEET has a remarkable safety profile after 40 years of use and nearly 8 billion human applications. Fewer than 50 cases of serious toxic effects have been documented in the medical literature since 1960, and three quarters of them resolved without sequelae. Many of these cases of toxic effects involved long-term, heavy, frequent, or whole-body application of DEET. No correlation has been found between the concentration of DEET used and the risk of toxic effects. As part of the Reregistration Eligibility Decision on DEET, released in 1998, the Environmental Protection Agency reviewed the accumulated data on the toxicity of DEET and concluded that 'normal use of DEET does not present a health concern to the general U.S. population.' When applied with common sense, DEET-based repellents can be expected to provide a safe as well as a long-lasting repellent effect. Until a better repellent becomes available, DEET-based repellents remain the gold standard of protection under circumstances in which it is crucial to be protected against arthropod bites that might transmit disease."

You can read the whole article here:

http://www.nejm.org/doi/full/10.1056/NEJMoa011699#t=articleResults

You quoted the exact article I posted. Which says exactly what I said.

I don't like to re-apply. I use a high concentration of DEET. I don't have to worry about forgetting it, bringing it with me, reapplying. Even when perspiring, I see no diminished effectiveness.

Point is, do what you'd like, but higher DEET concentrations are effective for a longer length of time. That's how it works. If you like lower concentrations and re-applying more often, go for it.