What type of mosquito repellent is most effective?

Question

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.).

Answer 1

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

Annals of Internal Medicine

N,N-diethyl-3-methylbenzamide (DEET) is the most effective, and best studied, insect repellent currently on the market.

CDC

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.

Answer 2

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.

Answer 3

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 (Off!, Cutter, Sawyer, and Ultrathon)
• Picaridin (Icaridin) (Cutter Advanced, Skin So Soft Bug Guard Plus, and Autan (outside the United States))
• Lemon Eucalyptus oil (PMD) (no examples given)
• IR3535 (Skin So Soft Bug Guard Plus Expedition)