Jun 17, 2025

Does Vitamin B12 prevent mosquito bites?Link to Does Vitamin B12 prevent mosquito bites?

A female Culicidae mosquito (a malaria vector) feeds on human blood. Many people seek natural mosquito bite prevention methods, including dietary supplements like vitamin B12. Anecdotal tips, from eating vitamin-rich foods to taking high-dose B12 pills, claim to make you less attractive to mosquitoes. But does taking vitamin B12 actually stop mosquito bites? This article examines the scientific evidence behind the “vitamin B12 mosquito repellent” idea and summarises what really works to keep those pesky bloodsuckers at bay.

Vitamin B12 mosquito repellent: myth vs. science

The origin of the B-vitamin repellent myth

The notion that B vitamins can ward off mosquitoes has been around for decades. In fact, it traces back to the 1940s when early reports (later found to be flawed) suggested that taking vitamin B (particularly thiamine, or B1) could prevent mosquito bites^[3,6]. This idea took hold in popular culture and persists through folk remedies and online advice. Some travelers even report being told to take B12 supplements for weeks before a trip to avoid bites^[6]. Meanwhile, others claim that consuming B12-rich foods (like Marmite or bananas) might attract mosquitoes by altering skin secretions^[6], revealing how contradictory these unscientific tips can be. Such widespread anecdotes underscore the confusion and the importance of looking at controlled scientific studies.

What the science says

Modern research has put the vitamin B theory to the test, and the results are clear: vitamin B12 (or any B vitamin) does not make an effective mosquito repellent. Controlled experiments and reviews have consistently found no significant difference in mosquito attraction between people who take B vitamin supplements and those who don’t^[2,3]. For example, a 2005 study in the Journal of the American Mosquito Control Association gave volunteers vitamin B supplements and then measured how attractive their skin scent was to mosquitoes. It found no evidence of reduced mosquito attraction^[2]. More recently, a 2022 systematic review of over 100 papers concluded unequivocally that oral thiamine (vitamin B1) “cannot repel arthropods in any dosage or route of administration”^[2]. In all properly controlled tests, vitamin B1 had no effect on mosquito biting rates, and no study has shown any other ingested supplement (including B12) to make humans repel mosquitoes^[3]. It turns out that mosquitoes are primarily attracted by factors like carbon dioxide exhalation, body heat, and the unique cocktail of odors produced by our skin microbiome. Factors which vitamins don’t meaningfully change^[1]. As one medical entomologist quipped, if vitamin B pills truly worked as mosquito repellents, “our supermarket shelves would be full of ‘mosquito repellent pills’” by now^[3]. Instead, no health authority endorses vitamin B12 or B1 supplements for bite prevention, and products marketed as “oral insect repellents” are not recognized due to lack of evidence^[3].

B12 supplements vs. B12 deficiency

What about vitamin B12 deficiency, could lacking B12 make someone more prone to bites? Scientifically, there’s no indication that B12 levels (high or low) have any appreciable effect on how much mosquitoes like you. Studies on thiamine (B1) found that people deficient in B vitamins were no more attractive to mosquitoes, and conversely those taking vitamin supplements didn’t become any less attractive^[3]. In other words, mosquitoes don’t care whether you had your vitamins. The U.S. Centers for Disease Control and Prevention (CDC) explicitly notes that ingesting vitamin B (or garlic, another folk remedy) is ineffective for preventing mosquito bites^[4]. The scientific consensus is that vitamin B12 does not prevent mosquito bites. This idea is a myth unsupported by rigorous evidence^[2,3].

Conclusion and practical advice

Vitamin B12 is an essential nutrient for many aspects of health, but using it as a mosquito repellent is not supported by science. There is no credible evidence that taking B12 supplements (or being deficient in B12) will have any meaningful impact on how much mosquitoes are attracted to you. So, if you’re looking to avoid those itchy welts, don’t rely on a B12 pill, focus instead on proven mosquito bite prevention strategies.

Proven ways to prevent mosquito bites

Use effective insect repellent: Apply an EPA-registered mosquito repellent on exposed skin. Repellents containing DEET, picaridin, IR3535, or oil of lemon eucalyptus (OLE) are safe and highly effective when used as directed^[4]. (No oral supplement can replace a good topical repellent!)
Wear protective clothing: When mosquitoes are active, cover up with long-sleeved shirts, long pants, and socks. Light-colored, loose-fitting clothing is best. You can even wear clothing pre-treated with permethrin (an insect-killing repellent) for added protection^[4].
Use bed nets when sleeping: Especially in malaria or dengue risk areas, sleep under an intact mosquito net (preferably insecticide-treated) to prevent night-time bites^[5]. Ensure windows and doors have screens, or use indoor insecticide sprays or coils in areas without sealed housing.
Time and place matters: Mosquito species that spread vector-borne diseases often bite most around dawn and dusk. When possible, limit outdoor exposure during these peak biting times or in mosquito-infested areas^[5].
Eliminate standing water: Mosquitoes breed in stagnant water. Regularly empty or cover any standing water around your home (e.g. flowerpots, buckets, birdbaths, gutters) to reduce local mosquito breeding sites^[5]. Even small puddles can produce hundreds of mosquitoes.

In summary, while the idea of a “natural” vitamin B12 mosquito repellent is appealing, the current scientific consensus is that it does not work^[2,4]. Mosquitoes are driven by factors that vitamin supplements simply don’t alter. To avoid mosquito bites (and the vector-borne diseases they can carry), your best bet is to use the well-established protective measures above. By combining good repellents with smart prevention habits, you can significantly cut down on mosquito bites.No mega-doses of B12 required. Stay safe and bite-free!