The idea that taking Vitamin B12 supplements prevents mosquito bites has circulated widely. Vitamin B12, chemically known as cobalamin, is a water-soluble nutrient with a complex structure. The anecdotal theory suggests that ingesting this vitamin alters a person’s body odor, making them unappealing to biting insects. This concept is appealing because it offers a simple, natural solution to a persistent outdoor annoyance. However, any claim about B12’s repellent properties must be tested against scientific scrutiny to determine its actual effectiveness.
Scientific Findings on B12 and Mosquitoes
Scientific research does not support the claim that supplementing with Vitamin B12, or any B vitamin, acts as a mosquito repellent. Controlled studies have consistently found no significant difference in mosquito attraction between subjects who took B vitamin supplements and those who took a placebo. The idea that B12 changes the body’s scent profile has not been validated in trials.
Mosquitoes are primarily attracted to human hosts by a combination of factors, including carbon dioxide, body heat, and specific chemicals on the skin’s surface. A 2005 study examined the effect of B vitamin supplementation on volatile skin components and found no evidence of reduced mosquito attraction. This suggests that B12 does not alter the chemical signals mosquitoes use to locate a blood meal.
The myth may have originated decades ago with flawed studies involving thiamine (Vitamin B1). The Centers for Disease Control and Prevention (CDC) does not endorse the use of B12 or other B vitamins for preventing mosquito bites. Relying on a B12 supplement leaves an individual vulnerable to bites and the potential for vector-borne diseases.
What Vitamin B12 Actually Does
Cobalamin is an essential nutrient required for several biological processes. It serves as a cofactor for enzymes involved in DNA synthesis, which is necessary for the creation of new cells. This function is important for the maturation of red blood cells, where a deficiency can lead to megaloblastic anemia.
Vitamin B12 is also indispensable for the healthy function of the nervous system. It supports the myelin sheath, the protective covering around nerve fibers. A long-term deficiency can result in irreversible neurological damage, causing symptoms like tingling, numbness, difficulty with balance, and cognitive decline.
Since the human body does not produce Vitamin B12, it must be obtained through the diet. Natural sources are almost exclusively found in animal products, such as meat, fish, eggs, and dairy. Individuals at higher risk of deficiency, such as vegans or those with pernicious anemia which impairs absorption, may require fortified foods or supplements.
Effective Methods for Preventing Bites
Since B12 is not an effective deterrent, people should rely on proven, evidence-based methods for protection against mosquito bites. Chemical repellents registered by the Environmental Protection Agency (EPA) offer effective personal protection. The active ingredients recommended by the CDC include DEET, Picaridin, and Oil of Lemon Eucalyptus (OLE).
DEET remains highly effective, with products containing 10% to 35% concentration offering adequate protection. Concentrations above 50% do not significantly increase the duration of protection. Picaridin, often used between 10% and 20%, is a popular alternative because it is nearly odorless and does not damage plastics or synthetic fabrics.
Oil of Lemon Eucalyptus (OLE or PMD) is a plant-based repellent recommended in 30% to 40% concentrations, providing protection comparable to lower concentrations of DEET. It is important to note that OLE is not the same as the unrefined essential oil of lemon eucalyptus, which is ineffective. Physical barriers also offer excellent protection, including wearing long-sleeved shirts, long pants, and ensuring window and door screens are intact.
Environmental control is a crucial preventative step, as mosquitoes require standing water to complete their life cycle. Homeowners should regularly eliminate all sources of stagnant water, as even a small amount is enough for some species to lay eggs. Sources of standing water include:
- Draining flower pot saucers.
- Cleaning clogged rain gutters.
- Disposing of old tires.