DEET concentration effectiveness?

Great question. I'd like to hear some feed back as well.

My anecdotal experience would be to the contrary. The Wind River range in later June and early July is a true marshy mosquito breeding ground and in that environment, I routinely found that I needed to loan out 90+% DEET to other instructors to keep mosquitoes at bay. 30% was OK if you didn't mind smearing it all over your skin, but with my higher octane juice, I could simply place it on the brim of my hat and a bandanna around my neck and this typically kept the biters at bay. This simply was not the case with the lower concentration.

Even so, I have mostly now converted to Cutter with Picaridin. It is not as strong as DEET, but I can safely put it directly on skin and not worry about it melting the nylon of my tarp or quilt.

I totally agree with the results of the tests done Backpacker magazine. It validated my opinion formed from years of buggy backpacking in Wisconsin: 3M Ultrathon is all a** kicking. That stuff REALLY works. It's expensive (10 bucks for a 1 oz tube) but given it is totally effective and one applications works a LONG time, I think it's really a bargain. I think I use one tube every 2-3 seasons. One application and I am generally good for the day. The formulation encapsulates the DEET in such a way that even after hiking and sweating I still don't have to worry about bugs. I may have to reapply some when I get to camp but I almost never get bit. I keep it in a BPL balm jar which is generally plenty for a weekend if used sparingly.

The article's negative was that it was "greasy" and "smelled bad". Well, after an extended weekend of backpacking in June heat I am generally greasy and smell bad on my own. Still, I don't find the aroma that offensive and I find that it "rubs in" fairly well.

I laughed my a** off at the lowest-ranked product: "You'll smell good while being bitten." Haha!

I do NOT use DEET to deal with ticks. These are a big problem in Wisconsin and this year has been over-the-top in terms of tick terror. I treat my clothes with permethrin. I can honestly say with good clothing choices and permethrin I have not had a tick in I can't say how long.

So I use DEET (3M Ultrathon) for flies, skeeters, etc and permethrin for the ticks. The two combined are a true "better living through chemicals" experience.

I was shocked at articles demonstration of the effectiveness of "Repel Lemon Eucalyptus". I have tried a lot of DEET alternatives and genearlly I have not been impressed. I have a lot of friends that refuse to use DEET and I am always wary of using it on my kids. I will have to give this stuff a shot with the wife (who is "anti-DEET") and kids.

I read somewhere that 15% DEET is just as effective as 100% DEET — the only difference being that the lower the concentration, the more frequently one must reapply the stuff.

For me, I dislike greasy lotions. I much prefer using 100% DEET where I can just bring a tiny bottle — and apply 6 drops — rather than bringing a whole tube and having to lather myself all over. 100% DEET is less weight and less fuss.

What I am curious about is that 100% DEET will supposedly destroy certain synthetic fabrics. I wear synthetics exclusively, and my pack and tent are both made with synthetic material. My 100% DEET has had ZERO effect on my gear. Pray tell, what specific types of synthetics should be kept away from 100% DEET?

Supposedly 30-some percent is the "point of diminishing returns" meaning that concentrations above this point don't produce a significant improvement in effective duration and you get better protection putting the DEET in a lotion that prevents it from washing off and controls the rate of evaporation from the skin.

That said, Benjamin is right on. If you don't mind more frequent applications then (to a point) lower concentrations work just as well. 5% is good for like an hour. We use a pretty low concentration on the kids and just reapply it as needed (for cookouts and such). It works well but we have to remember to keep wiping them down. They make repellent in "most towelette" form and one can do two small kids with one towel… I highly recommend these (for kids… not backpacking).

I know DEET will melt plastics. It fogged a spot on some cheap sunglasses I once owned.

I've been adding a few drops of water to my 100% DEET to stretch out my supply of it. I'm not really sure if that is effective or not. Oil and water don't mix.

I don't remember Ryan Jordon saying what they used in the Arctic. All I read was permethrin for the clothes. Ryan, what did you use or did you use anything?

When I was in the Arctic in 1979 we used a Vietnam era Army issued "Jungle Juice" that I think was 30% or so DEET with success. It melt nylon and plastic. I wouldn't use the stuff for very long. Interestingly, after four weeks of a six week trip we no longer itched or swelled up from the mosquito bites; our bodies had somehow managed to come up with an antitoxin.

Sawyer makes DEET, Permethrin, etc. According to their website, using Permethrin on gear and clothing plus DEET on skin is more effective than using either product alone…

All I know is I got the 100% DEET on my hands, then picked up a trekking pole, and the grip is still sticky. Kind of made me afraid of DEET. Luckily, I live somewhere that doesn't have bad mosquitos. I've had great luck with peremethrin on clothes to prevent ticks though.

I'm no repellent or bug expert, but a quick Google search turned up an interesting DEET hypothesis or two.

Research says that higher concentrations principally provide protection for longer. Found one claim that the duration is proportional to the logarithm of the concentration applied. So you would need to apply less often.

Also, one could theorize that the "other ingredients" in sprays are something that evaporates, like alcohols or similar. If this were the case, and you apply to skin, then all of the DEET and only the DEET in a given concentration would be on your skin, right? Meaning the only thing more dangerous about 100 percent DEET versus lower concentrations would be the ability to put on more per each application.

Anybody know if this is how it works?

What’s an effective concentration for DEET?
Is ‘agricultural’ Permethrin just as good?

Click here for a good article.

Read the section on "Controlled Release: (Sub-Micron Encapsulation)". That is why forumlations like Ultrathon are so effective and last so long with a 30-some percent concentration.

Good find, Benjamin. Interesting web site.

I've found Cutter Advanced to work without the stickyness of DEET. I don't use DEET anymore.

I find all of the comments regarding the effectiveness of various concentrations of DEET very interesting. My experience is parallel to Shawn's. If you really hate mosquitoes and they are really thick, everyone who has brought some other concentration all of the sudden becomes your best friend. Perhaps the one element we are missing in the discussion is that every person is different. Perhaps the chemical works differently because we differ in some manner. 100% DEET has never failed me from Alaska, to Idaho, Wyoming, Oregon and California so I keep using it even though it did once melt the plastic on my Swiss Army Knife.

During teh Artcic 1000 we only used the bug dope on two days out of 24 — they were not that bad. Only Ryan had the Pyrethrim treatment. Jason and I used nothing, other than the we day we reached the remotest spot and the day after that.

When they are bad I like a head net….

Diluting 100% DEET to 50% with alcohol works well in AK for most bugs — again, when they get really bad, you need a head net.

100% Deet also works well as a lubricant for sticky carabiners and cams and as a fire starter on toilet paper.

Hi folks,
Just thought I'd chime in on this discussion, as the editor who handled this story. It was a really interesting process, with some surprising results.The fact that DEET fared so well wasn't surprising, but the Repel Lemon Eucalyptus blew us away. It's definately what I'll be using this summer on myself and my kids.

Re: some questions about DEET damanging synthetics. I haven't witness any real damage when DEET contacts things like fleece or synthetic base layers or even nylon clothing. But I have seen it "melt" waterproof breathables, fabric coatings (like on a rainfly). I once spilled a couple drops on the toe of my son's sandals (an expensive pair of Tevas!) and it dissolved the rubber into a sticky mess that never really dried up. So much for those sandals.

Kristin Hostetter
Gear Editor
Backpacker

Kristin — does you boss know you're hanging out here ;-)

Just kidding. Glad to see you here.

Based on your article I went out today and bought some of the Repel Euclyptus. I'm really pumped about the possibility of replacing my tried-and-true Deet.

I'll be using it this weekend in a heavily forested section along the Missouri River in Nebraska — should be a good test of its effectiveness in the field. I'll post the results when I get back.

Repel Lemon Eucalyptus – this weekend I will also try it based on your recommendation

I have Eucalyptus extract and Lemon juice. I wonder if we could find the right mix and make our own.

Sounds like the smell would make good bear bait—-sniff, sniff, slurrpp… :-)>
One would really want to make sure that this is tucked away at night in a bear bag or canister.

And is this site being infiltrated by Cashpacker? :-P Welcome, Kristen.

>I have Eucalyptus extract and Lemon juice. I wonder if we could find the right mix and make our own.

It's an oil extracted from the leaves of the Lemon Eucalyptus (Eucalyptus citriodora) tree. Not quite the same thing.

I don't like the very strong smell of it. I would not call it a "pleasant smell". More like the aroma of sloth flatulence.

The directions caution you to use it only twice per day, and it claims to last for up to six hours. For a sweating hiker, I would bring that down to about three hours. A little over three hours after an application on my arms, I felt something on my arm and then watched a tick crawl quickly from my wrist to the bend of my arm. I flicked the tick off before it reached the sleeve of my tee.

For a few hours it was great at repelling bugs. I might use it for backyard sitting or short walks or perhaps "accidently" leave it during a visit, but will not use it for hiking again.