Citronella oil is a plant-based insect repellent derived from the leaves and stems of various Cymbopogon species, commonly known as lemongrass. The oil functions by masking the human scents, such as carbon dioxide and lactic acid, that mosquitoes are naturally attracted to, making it difficult for the insects to locate a host. Citronella is classified as a biopesticide, meaning it has a non-toxic method of action that deters pests without causing direct harm.
Preparing Citronella for Topical Application
Applying pure citronella essential oil directly to the skin is strongly discouraged because its high concentration can cause significant irritation or sensitization. Before use, the concentrated oil must be properly diluted into a carrier oil to create a safe topical repellent blend. Suitable carrier oils are those that are gentle and easily absorbed, such as fractionated coconut oil, jojoba oil, or sweet almond oil.
A safe and effective concentration for general adult use is typically a 2.5% dilution, which involves mixing about 15 drops of citronella oil into one ounce (30 milliliters) of the chosen carrier oil. This ratio ensures the repellent compounds are present without overwhelming the skin’s protective barrier. The mixture should be stored in a dark glass bottle to protect the essential oil from light degradation.
Before applying the blend over a large area, a small patch test is a necessary safety step. Rub a dime-sized amount of the diluted oil onto a discreet patch of skin, such as the inner forearm, and wait 24 hours to monitor for any signs of redness, itching, or swelling. Once the diluted oil is confirmed safe for your skin, apply a thin layer to exposed areas of the body, avoiding contact with cuts or broken skin.
Using Citronella for Area Protection
Citronella can be used to protect a fixed area, offering a more generalized deterrent that does not require direct skin application. The most common method involves burning citronella candles, which release the oil’s aroma into the immediate surroundings. These candles are best used in still air, as the repellent effect is highly limited in windy conditions and generally only provides a protective perimeter of a few feet.
Another effective way to distribute the oil in a sheltered space is through electric diffusers or essential oil lanterns. Diffusing a few drops of pure citronella oil indoors or on a covered porch allows its volatile compounds to saturate the air, establishing a scented zone that mosquitoes tend to avoid. The continuous release from a diffuser provides a more consistent level of repellent than the intermittent release from a burning candle.
Homemade area sprays offer a third option for treating outdoor furniture, screens, or patio surfaces, distinct from skin application. A simple spray can be created by mixing citronella oil with water and a dispersing agent, such as a small amount of high-proof alcohol or natural solubilizer, in a spray bottle. This mixture can be liberally applied to non-skin surfaces to help reduce mosquito presence in a specific outdoor living space.
Necessary Safety Precautions and Repellency Limits
Regardless of the application method, several precautions must be observed to ensure the safe use of citronella oil. The oil should never be taken internally, as ingestion can be toxic. It is important to avoid getting the undiluted or diluted oil into sensitive areas, especially the eyes and mucous membranes, as it can cause significant discomfort.
Individuals who are pregnant, nursing, or considering using the oil on young children should first consult with a healthcare professional before application due to the potential for increased sensitivity. Even with proper dilution, the oil can still cause mild skin reactions in people with high dermal sensitivity.
A major practical limitation of citronella oil is its high volatility, which means it evaporates quickly from surfaces and skin. Topical protection is typically short-lived, often lasting only 30 to 60 minutes before the majority of the active compounds have dissipated into the air. Frequent reapplication is therefore necessary to maintain a consistent barrier against mosquito bites.