How to prevent sweat washing off insect repellent?

Question

I just went on a 2 hour hike and was seriously annoyed by many insects that tried to get a bite of me. Through years of experimentation on hikes, I have so far arrived at using a 75% DEET solution that I liberally deposit over myself.

While very effective after application, I find that the effect only lasts around 15 minutes - presumably due to me sweating a lot, which might have a converse effect to the repellent (just speculating, really). On today's hike, I went through 50 ml of repellent, since I had to keep reapplying it often.

Is there a particular type of insect repellent that is effective in such situations? DEET has so far been the only thing I actually notice driving the insects away but I wonder if there are some more "sticky" formulations of it that might work (what I am using right now appears to just be a basic liquid solution without much additive effects). How do you cope with insects in such a case?

Answer 1

In the book Lightweight Backpacking and Camping, by Ryan Jordan, p. 307, Jordan says that a supply of DEET (presumably 100% concentration) for two weeks should weigh about 0.2 oz, including the bottle. That's about 0.001 ounces per hour of hiking. You used about 1 ounce per hour. Now Jordan is writing about how to go ultralight, so his rate of consumption may be low, but it still sounds like you were using hundreds of times more DEET than you needed to. The manufacturer of some 100% DEET I bought said that one application should last about 12 hours. This web page says that 5% DEET needs to be applied about every hour or two, so certainly you're doing the right thing by using a high concentration, if you're concerned about having to reapply it too often.

With 100% DEET, only a very tiny amount needs to be applied. Two common ways of achieving this are to carry a tiny plastic atomizer, or to put a fold-top plastic baggie on your hand for use as an applicator.

It sounds to me like you were using hundreds of times more DEET than you needed to in order to get the full effect, but you just weren't getting enough of an effect to be comfortable -- there is simply a limit on what DEET can do for you. You could try a head net, or you could change the times and places where you hike. Mosquitoes tend to be particularly active in the twilight hours, and thick in the springtime and near stagnant water.

Answer 2

You should keep in mind: DEET is not an insect repellent that will prevent insects from landing on your skin! DEET is a contact poison that will be very unpleasant for any insect who gets into contact with your skin - they essentially 'burn their feet'.

This prevents mosquitoes/black flies/knot/... from stinging you, but they will still try to land on your skin.

So you can literally take a shower in 100% DEET and not achieve your wished effect of never being bothered by a single insect.

Answer 3

I would recommend trying Repel Lemon Eucalyptus Bug Spray.

The Eucalyptus oil acts as a cooling agent and helps minimize sweating. I live in a deciduous ecosystem and can promise you this stuff works. In terms of lightweight: the bottle my husband and I use has been with us on multiple camping, climbing, biking, and kayaking excursions and we still have a good amount left. If you begin to run low you can add water and it will lengthen the life for at least 2/3 more days. We apply twice a day and it keeps the insect away. If you use deet for tick repellent try:

You can read up on DEET for yourself and family members (we take our girls camping).

Answer 4

I watch raptor nests which requires me to venture into the woods during the spring and summer. I have found that the best defense against mosquitoes is long sleeves and long pants. I wear a cycling jersey. It is comfortable in the hottest weather because it wicks away moisture. I have lightweight, zip-off legged pants. So, I can zip off the legs when I am done with my hike for the rest of the day. For my exposed areas (neck, face and hands) I use a Deet product. I spray the backs of my hands and rub my neck and cheeks. I have thought about getting a bug net for my head. I have also thought about using a bandana around my neck with a heavy application of the bug repellent instead of putting it on my skin. Maybe that might work for you.