The Health Benefits of Citronella Essential Oil

Natural insect repellent offers benefits in aromatherapy

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Citronella candles

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Citronella oil is a type of essential oil widely used in aromatherapy. Sourced from different species of Cymbopogon (lemongrass), citronella oil has been registered as an insect repellent in the United States since 1948. The aromatic compounds in citronella oil are commonly incorporated into soaps, lotions, sprays, candles, incenses, perfumes, and sprays.

In addition to preventing insect bites, Citronella contains a number of chemicals thought to enhance emotional and physical health. In fact, in some cultures, citronella oil is used internally as a deworming agent, to treat parasitic infections (such as amoebiasis), and to relieve diarrhea.

Citronella oil is generally intended for internal use only. While it is often used as a flavoring for food and beverages, citronella oil can become toxic when taken by mouth in larger quantities.

Health Benefits

Citronella oil is considered to be one of the more effective natural insect repellents. In addition, the oil contains compounds like methyl isoeugenol that exert potent antibacterial effects, making it useful for treating minor cuts and scrapes or controlling body odors caused by bacteria.

When applied to the scalp, citronella oil can moisturize the skin and hair, preventing dryness, flaking, frizziness, and dandruff.

When used in aromatherapy, citronella oil is said to help prevent or treat a number of common health conditions, including

  • Anxiety
  • Colds
  • Depression
  • Difficulty urinating
  • Flu
  • Menstrual cramps
  • Muscle spasms
  • Stomach ache

Some of these claims are better supported by research than others.

Insect Repellent

A 2011 review of studies in Tropical Medicine and International Health concluded that citronella oil combined with vanillin (a compound found in vanilla beans) was among the most effective natural insect repellents, providing up to three hours of continuous protection.

However, citronella oil is not nearly as effective as DEET (N-diethyl-3-methylbenzamide), a chemical repellent which offers up to 35 times more protection. In areas where mosquito-borne infections (like malaria or Zika virus) are common, citronella-based repellents will likely fall short.

Generally speaking, diffusers and sprays are more effective in preventing insect bites than citronella candles, the latter of which burn off a significant amount of the aromatic oils.

Aromatherapy

Alternative practitioners believe that essential oils used in aromatherapy offer health benefits when inhaled or massaged into the skin. There are two types of citronella commonly used for this:

  • Java citronella oil, derived from Cymbopogon winterianus
  • Ceylon citronella oil, derived from Cymbopogon nardus 

Of the two, Java citronella has higher concentrations of citronellal, the compound that gives the oil its distinctive lemony-herbal fragrance. Because of this, Java is considered the higher quality option.

Proponents contend that the aromatherapy oils can "re-modulate" the immune response and trigger the release of hormones and other substances that aid in the treatment of depression, indigestion, headache, insomnia, muscle pain, respiratory problems, skin condition, swollen joints, and urinary tract problems.

There is some evidence of this stimulatory effect. A 2012 study in the Journal of Health Research reported that the inhalation of citronella oil among 20 healthy volunteers resulted in a significant decrease in blood pressure, heart rate, and respiratory rate compared to their pretreatment value.

Moreover, brain activity measured by an electroencephalogram (EEG) showed that the inhalation of citronella oil triggered higher alpha and beta brain waves.

Although this suggests that citronella aromatherapy can aid in stress management and fatigue, there remains little evidence that it can effectively treat any medical condition.

Possible Side Effects

Citronella essential oil is considered safe when used appropriately. Current research suggest that it offers low toxicity when inhaled or applied to the skin. This doesn't mean it is without its concern.

When consumed internally, citronella oil can cause stomach upset, throat irritation, and coughing. If it accidentally gets into the eye, it can cause redness, irritation, and the temporary opacity of the cornea (a condition which usually reverses in a week or so).

When applied to the skin, undiluted citronella oil is not only irritating but may also cause tachycardia (rapid heart rate) in some. This is especially true of Java oil, in which high concentrations of citronellal have been known to trigger abnormal cardiovascular events.

Allergic reactions are uncommon but may occur if the citronella oil is applied excessively. Citronellal also has a photosensitizing effect, increasing sun sensitivity and the risk of sunburn.

You should also take care when using citronella oil for aromatherapy. Inhaling pure citronella oil can cause nose and throat irritation and trigger acute inflammation of the airways.

Dosage and Preparation 

There are no guidelines for the appropriate use of citronella oil. However, there are some safety tips that can help guide proper usage.

As a rule, pure citronella oil should not be applied directly to the skin. To avoid irritation and other reactions, citronella oil should be mixed with a neutral carrier oil (such as sweet almond, jojoba, or coconut oil) in a 1:1 ratio. Wash with soap and warm water after use, and avoid excessive sun exposure.

If you are prone to allergic dermatitis, apply a little oil to a small patch of skin and wait 24 hours to see if redness, irritation, or rash develops.

When used for aromatherapy, either apply a few drops to a cloth or tissue or use a commercial diffuser or vaporizer. Never inhale citronella oil directly from the bottle.

Citronella oil should never be taken internally without the supervision of a health professional. Even so, the internal use of essential oils is generally discouraged, according to a statement from the National Association for Holistic Aromatherapy.

What to Look For

Citronella essential oil is widely available online, in natural food stores, and shops specializing in aromatherapy and wellness products.

Essential oils are not regulated by the U.S. Food and Drug Administration (FDA) and do not have to meet any purity standards. As a result, the quality can vary from one brand to the next. To help make the right choicer:

  • Always read the product label. Only buy essential oils that have the Latin name (Cymbopogon winterianus or Cymbopogon nardus) and the country of origin on the product label. There should be no added ingredients.
  • Test the oil. Poor-quality essential oils are sometimes diluted with vegetable oil. You can tell this by placing a single drop on a piece of paper. If an oil circle develops around the droplet, you likely have a diluted product.
  • Don't be guided by scent. Some manufacturers will add artificial fragrances to cheaper oils. On the flip side, Ceylon oils will be far less fragrant than Java oils but still be 100% pure. Don't be fooled by a strong scent or misled by a weaker one.
  • Avoid plastic or clear glass bottles. Essential oils are easily degraded by oxidizing effects of ultraviolet (UV) radiation from the sun. For this reason, essential oils must be bottled in light-resistant glass bottles (usually dark amber or cobalt blue). Nothing else will do.

While some practitioners will tell you that Java citronella oil is "better" than Ceylon essential oil, there is really no evidence that one is more effective than the other.

With that said, Java citronella oil is "stronger" and is classified as Toxicity Category 3 (slightly toxic) compared to a Toxicity Category 4 (practically non-toxic) for Ceylon citronella oil.

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Article Sources

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