Does Vitamin B1 Keep Bugs Away? The Scientific Verdict

January 8, 2026 •

3 min read

According to a 2022 review of over 100 studies, oral thiamine (vitamin B1) cannot repel insects at any dosage or route of administration. This definitively debunks the persistent myth that vitamin B1 keeps bugs away by altering a person's body odor.

Quick Summary

For decades, the belief that vitamin B1 supplements could repel mosquitoes has persisted, but extensive research has proven this folk remedy ineffective. The science points toward relying on EPA-approved repellents and other proven strategies for reliable protection.

Key Points

Myth Debunked: Decades of controlled scientific studies have consistently shown that oral vitamin B1 (thiamine) is ineffective as an insect repellent.
Flawed Origins: The belief that vitamin B1 repels insects originated from anecdotal and poorly conducted research in the 1940s that was never scientifically validated.
Effective Alternatives Exist: For reliable protection, rely on EPA-registered repellents containing ingredients like DEET, picaridin, IR3535, or oil of lemon eucalyptus.
Mosquitoes Ignore Thiamine: Mosquitoes are primarily attracted to human breath (carbon dioxide), body heat, and specific skin odors, none of which are significantly altered by ingesting vitamin B1.
Safe Application is Key: Combine proven repellents with protective clothing, mosquito netting, and environmental management, such as removing standing water, for comprehensive protection.
The Danger of Ineffective Repellents: Relying on an unproven remedy like vitamin B1 can leave you vulnerable to bites from insects that carry diseases like Zika or West Nile virus.
Not All Naturals Work: Many common 'natural' alternatives, including eating garlic or using citronella plants, offer minimal to no real protection against insects.

The Origins of the Vitamin B1 Myth

The notion that ingesting vitamin B1, or thiamine, can ward off mosquitoes and other biting insects has a long history, dating back to flawed studies conducted in the 1940s. A 1943 case report from a Minnesota pediatrician claimed that children taking oral doses of thiamine were protected from bites, and this anecdotal evidence quickly spread. Despite subsequent failed attempts to replicate these results in controlled studies, the myth persisted through word-of-mouth.

The Scientific Evidence: A Clear Verdict

Numerous controlled scientific studies have consistently shown that thiamine supplementation has no effect on mosquito attraction. Research from 2005 and 2015, including studies involving vitamin B patches, demonstrated that these supplements did not reduce attractiveness to mosquitoes. A comprehensive 2022 review confirmed that oral thiamine is not effective as an arthropod repellent.

Why Doesn't Vitamin B1 Work?

Vitamin B1 is water-soluble, and excess amounts are excreted through urine, not in a way that deters insects through skin odor. Mosquitoes are attracted by factors such as carbon dioxide, body heat, and specific skin odors produced by the human microbiome, none of which are significantly altered by taking thiamine. Some entomologists even note that thiamine is nutritious for mosquitoes.

Effective Alternatives for Bug Control

For proven protection, rely on methods recommended by health organizations like the CDC, particularly EPA-registered insect repellents.

Comparison of Repellents: Oral B1 vs. Proven Solutions


Feature	Oral Vitamin B1 (Thiamine)	EPA-Registered Repellents (e.g., DEET, Picaridin)
Effectiveness	Ineffective. Controlled studies show no impact on bug attraction.	Highly Effective. Proven to repel mosquitoes, ticks, and other biting insects.
Duration	None. Excess is excreted by the body; no repellent effect is achieved.	Several hours, depending on concentration and product type.
Mode of Action	None. Does not alter key human attractants like CO2 and skin odor.	Repels bugs by interfering with their olfactory receptors.
Application	Ingestion of supplements.	Topical application to exposed skin and clothing.
Official Endorsement	Not Recommended by the CDC or other health authorities.	Recommended by the CDC and EPA for safe and effective use.

Additional Proven Methods

Remove Standing Water: Eliminate mosquito breeding grounds by regularly emptying containers that collect water.
Wear Protective Clothing: Minimize exposed skin by wearing long sleeves and pants outdoors.
Use Mosquito Netting: Provide a physical barrier against bites, especially while sleeping or sitting outside.
Time Outdoor Activities: Avoid peak mosquito activity times, usually at dawn and dusk.

Other Natural Remedies: Are They Any Better?

Many other "natural" remedies are also ineffective. Eating garlic does not repel mosquitoes, and citronella candles offer only limited protection. An exception is Oil of Lemon Eucalyptus (OLE), an EPA-registered plant-based repellent that provides effective protection comparable to DEET.

Conclusion

Scientific evidence definitively shows that vitamin B1 does not repel bugs. Relying on this myth can increase your risk of bites from disease-carrying insects. For effective protection, use EPA-registered repellents, wear protective clothing, and manage your environment by eliminating standing water. Trusting proven methods recommended by health authorities is the most reliable way to prevent bug bites. For the latest recommendations, visit the {Link: CDC's official guidelines https://www.cdc.gov/mosquitoes/prevention/index.html}.

Frequently Asked Questions

The belief is largely based on persistent folk remedies, anecdotal stories passed down over generations, and the power of confirmation bias. These personal accounts are not supported by controlled scientific evidence.

No, major health authorities, including the Centers for Disease Control and Prevention (CDC), state there is no reliable scientific evidence that any vitamin or dietary supplement can effectively repel biting insects.

The CDC recommends using EPA-registered repellents containing active ingredients such as DEET, picaridin, IR3535, or oil of lemon eucalyptus (OLE), which have been scientifically proven to work.

Most evidence refutes thiamine's effectiveness, even when applied topically. While some limited, contested pilot studies have explored topical thiamine hydrochloride, they contradict the larger body of evidence, and robust support is lacking.

Relying on an ineffective remedy can leave you exposed to bites from harmful insects that carry diseases like Zika virus, dengue, or West Nile virus, thereby increasing your health risk.

Much like vitamin B1, the claim that eating garlic repels mosquitoes has been scientifically debunked. A 2018 University of Sydney review found that while eating garlic can give your breath a strong odor, it does nothing to lessen your attractiveness to mosquitoes.

Besides using an effective repellent, you can wear long sleeves and pants, use mosquito netting, use fans to create air currents that deter mosquitoes, and remove any standing water around your home where mosquitoes breed.

The early 1940s studies were flawed and uncontrolled, meaning they lacked the rigor necessary for scientific validity. Subsequent, properly controlled experiments by various health organizations failed to replicate the initial findings.