Mosquitoes are not repelled by vitamins and other oral supplements you might take

People relying on vitamins as protection against mosquitoes can still get bitten, potentially putting them at risk of diseases.

A longstanding medical myth suggests that taking vitamin B1, also known as thiamine, can make your body repel mosquitoes.

A “systemic repellent” that makes your whole body unappealing to biting insects certainly sounds good. Even if you correctly reject the misinformation questioning safe and effective repellents like DEET, oral repellents would still have the benefit that you wouldn’t need to worry about covering every inch of exposed skin or carrying containers of bug spray whenever you venture into the great outdoors.

Along with thiamine, other alleged oral mosquito repellents include brewer’s yeast, which contains thiamine, and garlic, the legendary vampire repellent.

If oral repellents sound too good to be true, it’s because they are.

As a professor of entomology in Taiwan, where the mosquito-transmitted Dengue virus is endemic, I was curious what science really says about food-based repellents. After a very deep dive into the literature and reading practically every paper ever written on the subject, I compiled this knowledge into the first systematic review of the subject.

The scientific consensus is, unequivocally, that oral repellents don’t exist. Despite extensive searches, no food, supplement, medication, or condition has ever been proven to make people repellent. People with vitamin B1 deficiency don’t attract more mosquitoes, either.

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