There are many different kinds of insect repellents and bug sprays on the market: sprays and lotions, chemical and natural, huge percentages of DEET and lower percentages, etc.
What type of bug repellent is most effective against mosquitoes? What types should be avoided or are just a marketing ploy?
I'm not asking for specific product recommendations, but general advice about types of insect repellent (e.g. 100% DEET vs. 30% vs. citronella oil, etc.).
Mosquitoes love me, so I've had opportunity to try many variations of repellent. Most of the things you mentioned are effective immediately after application. For me, the difference is how effective they are after hours of sweaty hiking. For that, I lean towards high percentage DEET in a lotion-type formulation like 3M Ultrathon (that particular one is 35% DEET).
For the parts of you that are covered by clothing, I have had success with permethrin treatments, but I prefer just wearing clothes that mosquitos can't bite through (I don't know how to find this out without field testing).
DEET is supported by several studies
N,N-diethyl-3-methylbenzamide (DEET) is the most effective, and best studied, insect repellent currently on the market.
Of the active ingredients registered with the EPA, CDC believes that two have demonstrated a higher degree of efficacy in the peer-reviewed, scientific literature (See Publications page.). Products containing these active ingredients typically provide longer-lasting protection than others:
DEET (N,N-diethyl-m-toluamide)
Picaridin (KBR 3023)
Also make sure you apply sunscreen first.
EDIT: I suppose I should be clearer? nothing is more effective than DEET :) Sure it might melt your face off, but if the alternative is not going outside, I choose melty-face.
The CDC says Picaridin and DEET* are the best, with Oil of Lemon Eucalyptus** being something of a shorter-lasting runner-up:
Of the active ingredients registered with the EPA, CDC believes that two have demonstrated a higher degree of efficacy in the peer-reviewed, scientific literature (See Publications page.). Products containing these active ingredients typically provide longer-lasting protection than others:
- DEET (N,N-diethyl-m-toluamide)
- Picaridin (KBR 3023)
Oil of lemon eucalyptus [active ingredient: p-menthane 3,8-diol (PMD)], a plant- based repellent, is also registered with EPA. In two recent scientific publications, when oil of lemon eucalyptus was tested against mosquitoes found in the US it provided protection similar to repellents with low concentrations of DEET.
*I think it is important to note that 100% DEET is overkill:
DEET efficacy tends to plateau at a concentration of approximately 50%.
**: Caveat emptor:
“Pure” oil of lemon eucalyptus (essential oil) is not the same product; it has not undergone similar, validated testing for safety and efficacy, is not registered with EPA as an insect repellent, and is not covered by this recommendation.
Their full list also includes IR3535:
DEET can be harmful to the skin if you suffer from any skin disorders such as Eczema (as I do).
I have recently started using a product called Smidge when hiking in Midge infested areas of Scotland. More details can be found here. The manufactorers claim it works on a variety of biting insects including Midges, Ticks and Mosquitoes. It does work with Midges! I'm going to see if it works on Mosquitoes when I go to SE Asia later in the year!
I have in the past also used Repel 55 Insect Repellent Spray when travelling in Latin America and that seemed to work okay.
I wanted to add some points to the discussion, as well as list another product.
First, as noted, 100% DEET is overkill. Once you go over 35%, it doesn't get better. Second, DEET is not good for you. Not saying don't use it, but try to use the minimum needed.
What I like to use is permethrin. This is used on gear and clothing, not skin, and stays active for months. Once dry, it is odorless, colorless, & leave no residue that can be felt. And doesn't wash off. It's mostly an insecticide that kills insects that touch it, but I have found that it also works as a repellent as well. Not as good as DEET, but usually enough so I don't need the DEET.
Although it's sold in small containers in outdoor stores and departments, you can get it in a concentrate online that's much better deal.
