I've encountered some anecdotal evidence for massive B12 consumption, but nothing substantive.
Citronella oil is supposed to be effective.
Sulfur is actually an amazing mosquito repellent, but hard to utilize. Burning sulfur directly produces extremely toxic fumes, and eating large quantities of cabbage and egg yolk results in fumes you will only -wish- were toxic. (Although apparently some hikers do exactly that... I imagine they hike alone, however.)
Thank you! I had forgotten about citronella. I love cabbage and eggs, but I don't think I should do that to my husband. ;p
If it's worth saying, but not worth its own post, even in Discussion, it goes here.