Does a truly effectively odorless mosquito repellent exist? Can it?

[gomipile]

Someone I know would benefit from a mosquito repellent that is effectively odorless to humans. It would be used in a setting where there are many people sensitive to various herbal, chemical, etc. scents. Many of the people there have different overlapping and complementary sets of scents they are sensitive to or completely intolerant of. So, as a policy, nothing is allowed there that has any kind of noticeable scent that doesn't smell like a human or clothes cleaned with unscented detergent, and such.

So, does such a thing exist?

[Thomas Cardew]

There's two main insect repellents : DEET and Picaridin. DEET is the more common and in high concentrations has the bitter smell people associate with 'bug spray'. Picaridin is differently effective, better at some insects worse at others, but is nominally thought odorless by most people. Obviously, it will depend on your acquaintance's particular sense of smell but look for one with Picaridin as the active ingredient for them to try.

[Melayl]

There's a product called Thermacell that is (to me) odorless, and works very well on biting insects in a 10-15' radius. Does not work well in anything more than a light breeze, however.

Has kept mosquitoes, gnats, and ticks away when I'm out hunting.

[Khedrac]

Easy answer - "yes, but it may need tuning to the country".

Back in the 1970s and 80s my father bought an American "mosquito repellent" that was a small box which emitted the drone of a hunting dragonfly (a high-pitched whine that I was then young-enough to hear). (I think he bought it from Hammacher Schelmmer?)

We used the box on various holidays around the UK and, whilst not 100% effective, it did seem to work; also dad used it on many of his foreign trips (he travelled for work) and it worked for most of them too - I think the notable exception was Ghana where the mosquitos obviously hadn't heard of American dragonflies.

So, it truly was effective (if not 100%) and did not emit any odour at all - it was sound based instead.

As a side note, as a family we found that the mosquitos went for our mother over the rest of us (except perhaps for the dog) and we put that down to her not eating marmite (may or may not be an accurate guess).

[gomipile]

Thank you all for the advice. Hopefully one of these works for the people in question.