Gnats swarming the face are a common annoyance for outdoor enthusiasts and gardeners. These tiny insects are not flying randomly or out of malice. Instead, they are chemically and biologically attracted to the specific conditions and emissions created by the human head and face. Understanding these chemical signals reveals why you become an irresistible target for these small pests.
Why Your Face is an Ecosystem
The human face and head attract gnats because they provide biological necessities for survival. The primary signal drawing them in is the plume of carbon dioxide (CO2) exhaled with every breath. Gnats possess highly sensitive receptors that detect minute changes in atmospheric CO2, allowing them to locate warm-blooded hosts from a distance.
The CO2 plume leads gnats to sources of warmth and moisture. The head is typically the warmest and least covered part of the body, providing an ideal microclimate. Moisture vapor in exhaled breath, especially around the mouth and nose, offers a readily available source of hydration.
The face also provides essential nutrients like salts found in sweat and tears, which gnats require for metabolic processes. Tears and secretions around the eyes are particularly rich in protein and salt, making them a target for certain species. Subtle scents from cosmetics, hair products, or residual food particles on the breath also contribute to the chemical signature that lures these flies closer.
Identifying the Swarmers
The insects commonly called “gnats” are a collection of small flies, each with different motivations for targeting the face. The most notorious culprits are Eye Gnats (genus Liohippelates), which are specifically drawn to the moist secretions of the eyes and nose. These non-biting pests use spongy mouthparts to lap up tears and mucus, obtaining protein needed for egg development. They can also mechanically transmit bacteria that cause acute conjunctivitis, commonly known as pink eye.
Other common face-swarming pests include Phorid Flies and Fruit Flies. Phorid flies, often called scuttle flies, are attracted to decaying organic matter and moisture, but the CO2 in human breath also draws them close. Fruit flies are primarily drawn to fermented smells, meaning residual sweet scents from beverages or breath can attract them. Fungus Gnats typically breed in damp soil but may be attracted to the humidity and dampness of skin and hair in humid environments.
Strategies for Keeping Gnats Away
Minimizing skin attractants is the most effective personal strategy for deterring gnats. Since gnats seek moisture and salts, regularly wiping sweat from the face and neck reduces the chemical signals they follow. Avoiding strong, sweet-smelling personal care products, such as fruity shampoos or lotions, also removes scents that mimic their preferred food sources.
Physical Barriers and Airflow
Physical barriers offer immediate relief from swarming insects. Gnats are weak fliers, so a slight breeze or fan is often enough to keep them away. Wearing a wide-brimmed hat helps create a physical buffer zone around the face and disrupts the flow of the CO2 plume.
Natural Repellents
For a direct topical defense, many gnats are repelled by specific scents that mask the body’s natural odors. Applying diluted vanilla extract to exposed skin, such as behind the ears and on the forehead, is a popular natural method, as gnats find the scent repulsive. Essential oils can also be diluted with a carrier oil or water and lightly dabbed onto the skin, providing an effective barrier. Care must be taken to avoid contact with the eyes and mucous membranes when using these repellents.
The essential oils commonly used include:
- Citronella
- Peppermint
- Eucalyptus
- Lavender