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The National Taiwan University conducted a study dispelling the myth that vitamin B1 (thiamine) protects one from mosquito bites.

While some view the theory as farfetched, it hasn’t stopped people from testing it. It is more convenient for them to take a supplement than ensure they cover their entire bodies. Unfortunately, people have gone as far as creating brewer’s yeast, an oral repellant with garlic and thiamine.

A researcher compiled studies on the subject

Matan Shelomi, an entomology professor from the university, decided to investigate oral repellants. Shelomi comes from an area where the Dengue virus, which mosquitoes transmit, is common. So he looked into various papers on oral repellants and put his findings into a systematic review of the subject.

Shelomi found that scientists agree that oral repellants are non-existent. In addition, they have found no food or supplement to help people repel mosquitoes. Furthermore, people suffering from thiamine deficiency are not at a higher risk for mosquito bites. Despite this, the myth is hard to overlook.

How the myth began

The misinformation comes from a 1943 study by W. Ray Shannon. The Pediatrician from Minnesota gave different thiamine doses to 10 patients. The patients reported that the thiamine had prevented mosquito bites and reduced itching.

In 1945, Howard Eder, another pediatrician from California, claimed that 10mg of thiamine could protect from flea bites. Dieter Müting, a physician in the 1950s, also promoted this claim by stating that 200mg of thiamine could protect from bites as people went on vacation in Iceland. He claimed that the skin secreted a metabolic product of thiamine, thus repelling insects.

Other scientists immediately debunked these claims. Moreover, Californians in the 1950s found that thiamine could not protect their dogs from flea bites. Furthermore, the U.S. Naval Medicine Research Institute failed to replicate these results. Studies have since shown that neither garlic nor thiamine can repel mosquitoes.

Additionally, scientists have found that thiamine is as essential for mosquitoes as it is for humans; thus, they would have no reason to avoid it. There is also no evidence that they can smell it. The studies from Shannon and other doctors are likely due to desensitization, where participants no longer felt the symptoms despite the number of bites remaining the same.