The People's Perspective on Medicine

Will Vitamin B1 Scare Mosquitoes Away?

Some readers report that taking vitamin B1 (thiamine) can deter mosquito bites. Where mosquitoes carry disease, using a proven repellent would be wise.
Macro of mosquito (Aedes aegypti) sucking blood close up on the human skin. Mosquito is carrier of Malaria Encephalitis Dengue and Zika virus

Mosquitoes can put a real damper on enjoying the outdoors. When we were on our honeymoon, many years ago, we were camping in Grand Teton National Park. Even before we opened the car doors to set up our tent and camp stove, there were enormous mosquitoes hovering in large numbers to get a bite of our blood. Quite intimidating!

Why Are Some People Especially Enticing to Mosquitoes?

There seem to be significant differences among individuals with respect to how attractive mosquitoes find them. Some people start slapping biting mosquitoes the second they step outside, while others are rarely troubled at all.

A recent article at suggests several factors that may help explain this curious phenomenon. It turns out that blood type matters, and so does body temperature and the amount of carbon dioxide a person exhales. The microbial ecology of the skin may also have an effect on mosquitoes and their likelihood of taking a taste. Be wary at the backyard cookout: people drinking beer appear to be especially appealing to mosquitoes.

Does Vitamin B1 Scare Mosquitoes Away?

Q. I am a gardener and have always been a mosquito magnet. I read about vitamin B1 and have been taking it for several days. I just went outside this evening and didn’t get one bite! Usually they are all over me. I will continue to take B1 until cold weather.

A. There is almost no scientific research to support vitamin B1 (thiamine) against mosquitoes. That said, some readers report similar success. It may well be that thiamine works in conjunction with some of the other individual factors to make certain individuals less appealing.

We heard before from an individual who had good luck like you do:

Q. I have found vitamin B1 to be an effective deterrent for mosquito bites. I was recently in an area where I got multiple mosquito bites daily that itched unbearably. I developed open sores from scratching in my sleep, even when I used Benadryl or hydrocortisone cream.

In less than a week of taking vitamin B1 (500 mg per day), I have not had any more bites. I know there are studies that say vitamin B1 has no value for deterring insect bites, but my experience convinces me otherwise.

A. Thank you for sharing your testimonial. Some other readers have also found taking vitamin B1 (thiamine) helpful against mosquitoes. The research we have found, however, indicates that this vitamin is not effective as a systemic mosquito repellent (Journal of the American Mosquito Control Association, June, 2005). We could find no more recent research on the effects of thiamine against mosquito bites.

Another reader used B vitamins as a repellent in quite a different way:

Q. I was hiking high in the Canadian Rockies and the black flies were voracious. I didn’t have insect repellent with me because mosquitoes, fleas and other critters never bite me. I think that’s because I take B-complex and garlic, among other supplements, and they don’t like that.

Increasingly vexed by the black flies, I finally appropriated a B-complex 100 mg tablet I had with me. I smushed it up with some creek water, and then rubbed the bright yellow liquid all over myself. END OF PROBLEM! I admit, though, that I did look a bit jaundiced. What do you think about the efficacy of B-complex or other supplements in repelling bugs?

A. We love your story, but we’ve never heard of anyone else using vitamin B pills topically. With no studies, we wouldn’t dare venture a guess about effectiveness.

There was some preliminary research on thiamine, a B vitamin, taken orally to repel mosquitoes. Since it was conducted many decades ago, however, it would not meet today’s scientific standards and newer research has not confirmed the benefit. Nevertheless, some readers swear that this nutrient keeps mosquitoes from biting them.

Repelling Mosquitoes:

Individual body chemistry seems to have an important effect on whether and how well this remedy works. Most people need to apply a proven mosquito repellent such as DEET, picaridin or lemon eucalyptus oil. That is particularly true in places where mosquitoes may be transmitting malaria, Zika virus or West Nile virus. Although DEET sets the standard for repellents and has for decades, there are concerns about toxicity, especially if it is being used for extended periods or at high concentrations.

We have written here about mosquito repellents. It turns out that different species are more sensitive to one repellent than another (Travel Medicine and Infectious Diseases, Nov-Dec., 2013). That might explain why some people find taking thiamine helps, at least under certain conditions. Adding vanillin to mosquito repellents can extend the amount of time they are effective by about two hours.

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About the Author
Terry Graedon, PhD, is a medical anthropologist and co-host of The People’s Pharmacy radio show, co-author of The People’s Pharmacy syndicated newspaper columns and numerous books, and co-founder of The People’s Pharmacy website. Terry taught in the Duke University School of Nursing and was an adjunct assistant professor in the Department of Anthropology. She is a Fellow of the Society of Applied Anthropology. Terry is one of the country's leading authorities on the science behind folk remedies. .
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I have been doing the Vitamin B1 routine for over a month it has not helped in the least. I have had at least 50 mosquito bites this summer. I also heard taking garlic pills would keep them from biting you well that doesn’t help either. I don’t think anything works expect mosquito repellent.

I too have not ever gotten bit by mosquitos while taking vitamin B Complex 50. But when I stopped taking my B Complex I started to attract them and get bit.
Further more for Ladies, I’d like to report that while taking B Complex, I didn’t suffer with PMS or Cramps every month, but when I stopped them, the PMS and Cramps returned.

I am a gardener, and mosquitoes absolutely love to bite me. I’ve been taking a vitamin b complex, and once it gets in my blood system, they stop biting. I take it every day, and the only time I get bitten now, is when I forget to take it. My husband has also started taking it and is now not bothered by the mosquitoes. I’d like to know the specifics on the testing, if you know.

I have been a mosquito magnet for as long as I can remember. My now adult kids laughed and said I was crazy, but I get “lemon-size” swelling anywhere they bite. I am now a grandmother of triplets and guess what! One of my granddaughters is HIGHLY allergic as well. Her sister got stung by a bee last year, and several hours later you couldn’t even tell. There is some kind of genetic component to the theory about bug bites.

I spent time both in Alaska and Canada on the tundra, the first time in the Yukon Territory of Canada and got eaten up by mosquito’s every time I stepped out of the vehicle, they would swarm. My doctor suggested taking B-1 in minimum 500 mg doses three times a day, basically in the morning, early afternoon and evening. That way you keep the level in your system at a higher level. He indicated that the side effect would be having very dark and smelly pee. The next time I was in Alaska on the tundra, I started the B-1 three days before going and it worked like a charm, not a single bite, even though they would be around me. He was absolutely right about the side effects though. My wife went one time with me and likewise did the B-1 and she didn’t have any bites either.

Hi Peter,
Could you confirm the dosage of B1. I see typical capsule content of 1.5 mg, milligrams. You mention 500mg, 3 times daily, which is 1000 times that.
Did you mean 500 mcg, micrograms?


Actually the B vitamin doesn’t repel nor stop mosquitos or fleas from biting and if your body is lacking you will get a reaction i.e. an itchy bump. Supplementing with the vitamin stops you from having a reaction from the bite. In the 1960’s my 2 year old was covered in sand flea bites while my son had none. After visiting my family doctor, who greatly reminded me of Dr. Welby, I asked why one was getting bit and the other not and he had a great laugh and then explained that they were both getting bit but my son wasn’t having a reaction. He prescribed what my 73 year old brain remembers to be B6 and not B1 and within a month my daughter was no longer covered with bites. Of course due to the 73 year old memory it could have been B1.

The B Complex works for me too.

B1 has thankfully been a mosquito repellant for me as well! I am definitely a mosquito magnet, but as long as I keep taking B1, they don’t find me appealing.

Since vitamin B1 works really well for some of us but not others, perhaps the difference in effectiveness is the presence or absence of the MTHFR gene anomaly, which inhibits vitamin B uptake. If 40% of people of European descent carry this anomaly, that might explain why the experiments fail to find it working consistently.

60% of Caucasians would not be helped at all by B1 to prevent mosquitoes; mixed race folks – many more of us daily – would show little to no effect; and in a deliberately randomized sample (racially speaking) used for research purposes, those folks (lacking the MTHFR anomaly) would not benefit at all.

Their bodies just absorb and use the B1 rather than excrete it. If it only helps people whose bodies are not absorbing but only excreting the B1, and only that MTHFR group fits the bill, it would also explain why it would work on the skin of some people but not work for them if ingested. Just a thought.

I hope this posts in the right place: that is a brilliant thought about the MTHFR interaction!! I heard about MTHFR on Down syndrome groups about 7 years ago though we haven’t been tested. I am a very low mosquito attractor. And I assume I have at least one MTHFR mutation because I have one daughter with DS and another with autism (totally healed with biomedical interventions many years ago, she is a typical 13 year old now!)

When I was young, in the 1970’s, I was prescribed vitamin B-1 in a cherry wine base to drink due to mosquito bite reactions, and this worked for me! If I took before going outside, I rarely got a bite.

If I forgot, I took some when I came in and the bite went away faster and stopped stinging faster. The bites caused a stinging for me, worse than an itch…

I born in USA and I move to the Philippines, mosquito bites is the number one problem for me, i am not why the locals dont get bite, well i was using B1 500mg every day and i did not get mosquito bite, i will keep inform but i feel really ok included my bones..

I use thiamine when I hike. Normally, the skeeter bite immediate upon landing. When I take thiamine 300 mg I can smell the vitamin on my skin. It smells like a vitamin bottle and is strong. When a skeeter landed on my hand, I watched it. It walked around on my hand for a few seconds, then flew off without biting.

I used a Bounce Fabric Softener strip pinned to my collar and the mosquitoes left us alone all summer. Has to be the original formula.

My son was a flea magnet and further more, one bite lead to hives. Vitamin B1 tabs seemed to solve that problem. By the way, back then, we had large dogs and flea collars were almost useless and none of today’s flea meds for dogs were yet discovered. I added B1 to my dogs diet and it helped.

For years now mosquitos rarely bite me. Some do once in a while but I never get a bump that gets itchy. I did when I was a kid though.
Could this be because I took allergy shots for 10 years a long time ago. There may have been something in that shot that has saved me from pesky mosquitos.

I haven’t been bitten in years, even before addding B12. I suspect that my other meds have made me “distasteful”.


YES, Mosquitoes really do not bite since they do not have teeth, but female Anopheles mosquitoes inject us with their saliva. This is alkaline and produces itching. It helps her withdraw some of our blood.

Anyway, after we have been injected with this itchy saliva there is a simple remedy for this problem. Since the saliva is alkaline, we can neutralize it with an acid solution. That solution is vinegar.

Take a tissue or cotton swab, wet it with vinegar and apply it to the injected area. Hold it on for about twenty minutes so the vinegar can penetrate. This will solve the itch.

Vinegar is 5% acetic acid and non-toxic.

I have contact dermatitis, so I avoid scented products. Mosquitoes never bite me. But I noticed that if I wash my hands with scented soap in a public restroom, they will bite my hands.

This may not help everyone, but may be helpful to some.

I have some concerns about DEET. When camping, one of my companions slathered on the DEET, then poured a wine into a plastic wine cup (acrylic or polycarbonate, I’m not sure which). Her finger prints are permanently etched into the wine glass.

We’re not talking about disposables here. These cups are thick, dishwasher-top-tray-safe, clear, reusable cups. I’m hesitant to consume a product that etches plastic.

I just read that krill oil is better that fish oil. I don’t take either one. Should I? I was once told by a doctor that people don’t need to take supplements it’s the companies that sell them that say you need them. What do you say?

Hi! I am afraid of applying potentially toxic chemicals to my body, so I researched other means of repelling mosquitoes. I first tried a combination of lavender, eucalyptus, and peppermint oils. They were somewhat effective and repelled the bugs for about a half an hour. Then I came across an article that mentioned that Northeast Native Americans have used sage oil for centuries. So I bought a bottle of pure sage oil in a health food store and BINGO! It worked like a charm. It repels the bugs for about an hour and a half. You can apply it to your skin it as much as you want and it stays effective. I grow sage in my garden, so I picked a bundle of it and put it in the campfire, and it is wonderful at keeping the bugs away altogether. It even works with bees! The fragrance is pleasant and I will never need to buy a chemical again.

You mention that vanillin added to insect repelent will extend its coverage. What is vanillin?

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