July 21st, 2010
03:03 PM ET

Can vitamin B12 prevent mosquito-transmitted diseases?

From Peter Bartok, Houston, Texas

"Malaria is a major problem in the world. As a geologist I have done significant field work in malaria infested regions. Before doing work in Bolivia (several years ago) a doctor told me to take 1000 units of B12 three times a day. B12 exudes a mosquito repellent smell. During the six weeks I was there I was not bitten by mosquitoes. Can B12 prevent mosquito transmitted diseases? Thanks for being available."


Since mosquitoes are perhaps the most insidious disease-spreaders around, your question is important. Mosquitoes transmit parasites that cause malaria, a disease that kills between 1 million and 3 million people a year worldwide.

Before I answer your question, Peter, I would like to clarify one point. You asked whether vitamin B12 can prevent mosquito-transmitted diseases. What I think you are asking is whether B12 can repel mosquitoes and thus prevent transmission of the disease. This is an important distinction because, as you are probably aware, many mosquito-transmitted diseases like malaria and West Nile Virus are not necessarily preventable. The best we can hope for is stemming the number of people stung by these infected mosquitoes.

Now, to answer your question, the notion that ingesting certain products like B vitamins (or garlic, for that matter) might repel mosquitoes is common, but unfounded. Based on scientific studies I was able to dig up, B vitamins are not effective mosquito repellants, and vitamin B12, specifically, is not well-studied.

What scientists know more about is another B vitamin - B1 - also known as thiamine. As part of a larger survey of effective mosquito repellants, a 2002 study in the New England Journal of Medicine reported that, "No ingested compound, including garlic and thiamine (vitamin B1), has been found to be capable of repelling biting arthropods."

The same study concluded that DEET-containing products offer the best protection.  In addition to DEET, the Centers for Disease Control and Prevention recommends another product, Picaridin, and products containing oil of lemon eucalyptus. The CDC also recommends wearing long sleeves and pants while outdoors, and applying a repellent on your clothing.

soundoff (29 Responses)
  1. Odalice Yolanda Feliz

    Damn mosquitos, thank god for bug repellent! or vitamin B12 in ur case...

    July 21, 2010 at 18:08 | Report abuse | Reply
  2. RAJ

    My sister is adopted. She and her son attract mosquitoes for some reason. The family joke is that the only reason we invite them to out door events is to keep the mosquitoes away from us. I on the other hand am rarely the target of a mosquito. Has there been a study of the chemical differences between groups of people like myself and my sister? What is attracting the mosquito to my sister. My guess would be a chemical "scent" or sensing how close the blood is to the surface of the skin.

    July 22, 2010 at 14:08 | Report abuse | Reply
    • Joe

      Good question. I can be outside in a group of 30 people, and I'm the one swatting like a madman. I have no idea why mosquitoes like me so much; my family used to say "They know a good thing when they see it". Grrr.

      August 17, 2010 at 13:36 | Report abuse |
  3. Stacie

    Either way, I still have to get my monthly B-12 shot. Oral ingestion is out of the question for me because my digestive system does not absorb the vitamin. So shots it is... for the rest of my life.

    RAJ – I'm thinking it is something along the lines of mosquitoes are attracted more to those whose blood vessels are closest to the surface.

    July 22, 2010 at 18:12 | Report abuse | Reply
    • Nate

      Stacie, my background is in medicinal chemistry. Here's a little tid bit for you to try if you hate the shots. The part of the gut that absorbs the B12 is very short and malabsorption is common, but overall absorption is somewhat concentration dependant. Since that's the case, try a daily dose of sublingual Vit B12 at a 5000mcg (5 thousand – not hundred) dose. This should get your B12 levels as high or higher than monthly B12 shots and is usually lots cheaper.

      July 22, 2010 at 21:12 | Report abuse |
    • Rita Louise

      I had given myself B12 shots for over 20 years and recently started taking liquid B vitamins sublingually and seem to be doing ok. Both my B12 levels and my iron are fine.

      August 7, 2010 at 23:36 | Report abuse |
  4. jj

    NPR had a story today about mosquitoes. They agreed that none of the folk remedies work, and that some people attract mosquitoes more than others. Up north, I used to be able to feel mosquitoes land or bite. But the Tiger mosquitoes they have down here bite with no sensation. And while they don't make me itch much, I'd rather avoid west nile...
    We live on a lake in Atlanta, and the mosquitoes are so thick down here we avoid going out. That, and the heat...

    July 22, 2010 at 23:45 | Report abuse | Reply
  5. Mo

    Have been using B123 complex vitamins and brewers yeast tablets since the mid 70s – works on humans and dogs as well. Have made it thru some bad tick years as well as mosquito years. Just a hiint – it doesn't work immediatley – takes about a week for it to start working – was told "back in the day" by some country folk that it puts a nasty taste on your skin – I don't care about that, or the chemsitry end – IT WORKS!!!!!!!!

    July 23, 2010 at 09:42 | Report abuse | Reply
  6. Steven

    I made a comment about this post that was courteous and professional. I disagreed with you but that doesn't seem a reason to censor me. Why was it removed??

    August 5, 2010 at 04:36 | Report abuse | Reply
  7. EddyKong

    Vitamin B12 deficiency symptoms are manifest not because people are taking less vitamin B12 than recommended. Deficiency of vitamin B12 affects every cell in the body, but is most severely felt in the tissues where the cells normally divide rapidly, as in the blood-forming -tissues of the bone marrow and in the gastro-intestinal tract. The deficiency can also lead to neurological changes such as numbness and tingling in the hands and feet. It also include mood disorders, anxiety, insomnia, restlessness, night terror etc.

    November 11, 2010 at 08:12 | Report abuse | Reply
  8. Bayard Carey

    My girl friend and I have tickets to go to The British Virgin Islands.

    She has now done some research and tells me that there is a dangerous outbreak of Dengue Fever in the Virgin Islands. Should we cancel our trip?

    June 1, 2011 at 20:41 | Report abuse | Reply
  9. Duane Patterson

    For years I completed 50 to 100 mile back packing trips. Mostly in Yellowstone. We also took mega doses of b12 and mosquitoes stayed away. Note that once you start taking it, you do not want to shower until your trip is over or you will have a day that the mosquitoes come back for revenge.

    June 13, 2015 at 21:24 | Report abuse | Reply
  10. Duane Patterson

    also we did start taking the B12 days before leaving on our trips. It does work.

    June 13, 2015 at 21:31 | Report abuse | Reply
  11. sdorttuiiplmnr

    Hello.This article was extremely fascinating, especially because I was searching for thoughts on this matter last Saturday.


    June 27, 2015 at 03:23 | Report abuse | Reply
  12. Danoj

    Has anyone tried Fenugreek? I have it in tea and it leaves a strong smell on you skin for hours, think it should repel the mosquitoes in that it will disquise the smell on your skin that leads them to you in the first place.

    September 14, 2016 at 07:14 | Report abuse | Reply
  13. Dina Brookes

    I had dengue fever in Fiji, now I take B6 tablets 100mg once a day in summer never get bitten by mozzies. Friends are all bitten but I can now have peace of mind. You need to take them 2 weeks before mozzie season.

    January 14, 2019 at 02:59 | Report abuse | Reply
  14. Michele

    True or not, it works for me. I am in my 50s and have been a mosquito feeding station my entire life...until I started a B-complex.

    I first started it in spring 2011 because I was going to be in a wedding and had a trip to a lake in Montana a few weeks before. I didn't want to show up to the wedding with mosquito bites all over me! Two weeks later I started noticing less and less bites. Within one month I stopped getting bite completely. It was awesome!

    Last year I moved 3 times and life got hectic. I forgot about picking up extra B vitamins and I ended up with several bites one weekend. I started B complex the next day and have yet to receive another bite.....and I live on the lake now!

    It's worth a try. It's not bad for you to take, and you can't really take too much as it is water soluble and you will pee out what you don't use. If it works? AWESOME! If it doesn't??? Well, I guess your pee is a little more valuable than it used to be.

    Just sayin'......

    April 8, 2019 at 22:30 | Report abuse | Reply
  15. Linda Dillon

    When I lived in Italy I found that I would always get bitten and those around me were saved, Two things helped me to deter them. 1. Drinking a tot of Zambuca ( or anything aniseed Anise Pernod etc) 2. Drinking a bottle of tonic water (but only the ones with quinine in. Lidl was good for that! Also I bought a mosquito attractant machine, which they would collect in and , have to say I really enjoyed mashing them up and flushing them away. The lemon candles etc were good to a degree but having the tot of aniseed I think was the most effective.

    February 26, 2020 at 12:14 | Report abuse | Reply
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