Fact or Fiction: What Vitamin to Take to Stop Bites?

January 12, 2026 •

3 min read

For decades, people have believed that taking a specific vitamin, particularly vitamin B1 (thiamine), can repel mosquitoes and other biting insects. However, controlled scientific studies have found no evidence that any oral supplement, including those with B vitamins, is effective as a systemic insect repellent.

Quick Summary

This article explores the myth surrounding vitamin supplements as insect repellents, presenting scientific evidence that debunks the theory. It details what truly attracts mosquitoes and provides effective, proven alternatives for bite prevention, including CDC-recommended topical repellents and practical environmental controls.

Key Points

No vitamin stops bites: Scientific evidence confirms no oral supplement, including vitamin B1 (thiamine), effectively repels biting insects like mosquitoes.
The myth originated in flawed studies: Early reports from the 1940s suggesting vitamin B was an insect repellent were disproven by later, controlled research.
Mosquitoes are attracted by other cues: Insects find humans based on carbon dioxide, body heat, and unique skin odors, not altered by oral vitamin intake.
CDC recommends proven topical repellents: For effective protection, use EPA-approved topical repellents containing DEET, picaridin, IR3535, or oil of lemon eucalyptus (OLE).
Relying on vitamins is dangerous: Trusting unproven remedies can leave you exposed to mosquito-borne diseases like West Nile or Zika, especially in endemic areas.
Practice environmental control: Eliminate standing water around your property and use protective clothing and screens to reduce mosquito breeding grounds and risk.
Oral repellents are not FDA-recognized: The FDA declared oral insect repellents misbranded and unsafe, reinforcing the lack of scientific basis for such products.

The Origins of a Persistent Myth: Vitamins and Insect Repellents

The notion that consuming a vitamin, specifically vitamin B1 (thiamine), could deter biting insects originated from a flawed 1943 study. Despite subsequent research refuting this claim, the belief persists through anecdotal accounts and online misinformation. The theory suggested high doses of thiamine would lead to a skin scent repellent to insects.

Why the Vitamin B Repellent Theory Fails

Ineffective odor change: Studies indicate vitamin B supplements do not significantly alter human skin odor to repel mosquitoes. Excess water-soluble vitamins like B1 are quickly excreted, limiting any potential odor impact.
Mosquitoes aren't repelled by vitamins: Research indicates mosquitoes are not repelled by thiamine; in fact, they may perceive it as nutritious.
Mosquitoes are drawn to other factors: Mosquitoes are primarily attracted to carbon dioxide, body heat, and individual skin microbiome odors, which are largely genetic and unaffected by vitamin intake.

Scientifically Proven Methods to Prevent Bites

Effective bite prevention relies on evidence-based strategies. The CDC and EPA endorse several safe and effective methods.

Use effective insect repellent: Apply EPA-registered repellents with ingredients like DEET, picaridin, IR3535, or oil of lemon eucalyptus (OLE) to exposed skin and clothing.
Wear protective clothing: Cover up with loose, light-colored long sleeves and pants during peak insect activity. Consider permethrin-treated clothing and gear for added protection.
Control your environment: Eliminate standing water, where mosquitoes breed. Use screens and consider devices like thermacell for localized protection.

Comparison of Insect Repellent Methods


Method	Effectiveness	Duration	Pros	Cons
Topical Sprays (DEET, Picaridin)	High	Up to 12-14 hours	Highly effective and long-lasting protection	Can damage some plastics; must be applied carefully
Treated Clothing (Permethrin)	High	Up to 70 washes	Offers long-term protection on clothing and gear	Not for direct skin contact; only protects covered areas
Environmental Controls	Medium to High	Ongoing	Reduces mosquito populations at the source; can be combined with other methods	Requires consistent effort; doesn't offer immediate, personal protection
Oral Supplements (e.g., Vitamin B1)	Ineffective	Variable (depending on dose and excretion)	No topical application needed; appeals to natural remedies market	Scientific consensus shows it does not work; relying on it poses health risks
Natural Topicals (OLE)	Medium	Up to 6 hours	Plant-based, often has a pleasant scent	Requires frequent reapplication; not for young children

Potential Dangers of Relying on Unproven Methods

Relying on unproven methods like vitamin B supplements for bite prevention is risky. Biting insects can transmit serious diseases such as malaria, dengue, West Nile virus, and Zika. In areas where these diseases are prevalent, forsaking proven repellents for ineffective remedies can endanger your health. The FDA has banned marketing oral insect repellents due to their lack of efficacy.

Conclusion

Scientific evidence does not support taking any vitamin to stop bites. The myth surrounding vitamin B1 is not backed by controlled studies. For effective protection, use EPA-registered topical repellents, wear protective clothing, and manage your environment to reduce insect populations. These evidence-based strategies offer safe and reliable bite prevention. Avoid relying on unproven folk remedies that could compromise your health. Consult the CDC for more information on effective bite prevention.

Frequently Asked Questions

No, scientific evidence does not support the idea that taking a vitamin B complex can stop insect bites. Controlled studies have shown that these supplements do not affect your attractiveness to mosquitoes or other biting insects.

No, taking vitamin B1, or thiamine, has been scientifically proven to be ineffective as a mosquito repellent. The myth dates back to flawed studies and lacks modern scientific support.

The primary danger is a false sense of security. Relying on an unproven remedy like vitamin B supplements can leave you vulnerable to bites from insects that transmit serious diseases, such as malaria and dengue fever, especially in high-risk areas.

Mosquitoes are primarily attracted to the carbon dioxide we exhale, body heat, and the specific mix of odors produced by the bacteria on our skin. Genetics and physiological factors play a much larger role than dietary vitamins.

Health authorities like the CDC recommend using EPA-registered topical insect repellents with active ingredients such as DEET, picaridin, IR3535, or oil of lemon eucalyptus. These have been proven safe and effective when used as directed.

Some plant-based oils, such as oil of lemon eucalyptus (OLE), are recognized by the EPA as effective repellents, although they may not be as long-lasting as synthetic options like DEET or picaridin. Other natural solutions, like garlic or brewer's yeast, have been disproven.

To prevent bites, you can also wear protective, loose-fitting, light-colored clothing; treat clothing and gear with permethrin; and eliminate standing water around your home to reduce mosquito breeding grounds.