# Does ingesting vitamin B12 help repel mosquitoes? **URL:** \ **Category:** Factual Questions\ **Created:** [November 21, 2002, 1:25pm UTC](https://boards.straightdope.com/t/does-ingesting-vitamin-b12-help-repel-mosquitoes/137922 "2002-11-21T13:25:27Z")\ **Posts on this page:** 4\ **Page:** 1
**Author:** ![Johnny\_B.Goode](https://avatars.discourse-cdn.com/v4/letter/j/958977/32.png) [@Johnny\_B.Goode](https://boards.straightdope.com/u/Johnny_B.Goode)\ **Post date:** [November 21, 2002, 1:25pm UTC](https://boards.straightdope.com/t/does-ingesting-vitamin-b12-help-repel-mosquitoes/137922/1 "2002-11-21T13:25:27Z")
I am planning on taking a trip to East Timor where a number of insect-borne diseases exist. A friend told me that taking vitamin B12 is an effective repellent for mosquitoes. I was somewhat sceptical but did a bit of a search on Google. What I found was a bunch of references to this but nothing that seemed particularly credible. Just what is the straight dope on this? Are there any natural insect repellents which are proven to be effective or should I just stick with long sleeves and DEET? ---
**Author:** ![Philster](https://avatars.discourse-cdn.com/v4/letter/p/13edae/32.png) [@Philster](https://boards.straightdope.com/u/Philster)\ **Post date:** [November 21, 2002, 3:10pm UTC](https://boards.straightdope.com/t/does-ingesting-vitamin-b12-help-repel-mosquitoes/137922/2 "2002-11-21T15:10:16Z")
Can you control the CO2 you breath out? If so, then you stand a chance. DEET is the only repellent that has scientific tests to support it’s effectiveness. A few studies found that higher concentrations worked better than lower ones. Just recalling that Deep Woods Off was one of the most effective and had one of the highest levels of DEET b12 = total BS. ---
**Author:** ![Duck\_Duck\_Goose](https://avatars.discourse-cdn.com/v4/letter/d/50afbb/32.png) [@Duck\_Duck\_Goose](https://boards.straightdope.com/u/Duck_Duck_Goose)\ **Post date:** [November 21, 2002, 3:32pm UTC](https://boards.straightdope.com/t/does-ingesting-vitamin-b12-help-repel-mosquitoes/137922/3 "2002-11-21T15:32:23Z")
Vitamin B12 is naturally found in animal foods. [http://www.cc.nih.gov/ccc/supplements/vitb12.html#provide](http://www.cc.nih.gov/ccc/supplements/vitb12.html#provide) > [@](#): > > Vitamin B12 is naturally found in animal foods including fish, milk and milk products, eggs, meat, and poultry. > > \< snip \> > > Vegetarians who do not eat meats, fish, eggs, milk or milk products, or B12 fortified foods consume no vitamin B12 and are at high risk of developing a deficiency of vitamin B12 (9, 25). When adults adopt a vegetarian diet, deficiency symptoms can be slow to appear because it usually takes years to deplete normal body stores of B12. However, severe symptoms of B12 deficiency, most often featuring poor neurological development, can show up quickly in children and breast-fed infants of women who follow a strict vegetarian diet (26). If it were true that eating more B12 repels mosquitos, then I would expect persons, and cultures, with diets high in animal protein not to have as many problems with mosquitos and mosquito-borne illnesses as persons, and cultures, with diets low in animal protein. But I have never heard that meat-eating people have fewer problems with mosquitos and mosquito-borne illnesses than vegetarians. ---
**Author:** ![Peregrine](https://avatars.discourse-cdn.com/v4/letter/p/a6a055/32.png) [@Peregrine](https://boards.straightdope.com/u/Peregrine)\ **Post date:** [November 21, 2002, 4:33pm UTC](https://boards.straightdope.com/t/does-ingesting-vitamin-b12-help-repel-mosquitoes/137922/4 "2002-11-21T16:33:48Z")
This claim is usually made for B1, not B12, but in any case it remains unsubstantiated. See, for example, [The Pharmaceutical Journal](http://www.pharmj.com/Editorial/20000826/education/travel_bites.html) Vol 265 No 7111 p298-304: “There is some anecdotal, but little research-based, evidence that thiamine tablets taken at a dose of 50mg per day can offer protection against mosquito bites. The tablets need to be taken regularly and this method of bite avoidance should not be advised for those visiting malaria endemic areas.”