Shedding Light On Phototoxicity: Essential Oils To Beware Of


Essential oils, especially those containing a lot of terpenes like citrus, may have phototoxic properties. Terpenes are organic compounds with the physical property to absorb UV light and cause sunburns. If you happen to be using an essential oil at the beach, you would need to be wary of spending too much time in contact with this sunscreen-free zone for your health as a result of wearing sunscreen without having an SPF rating. This is particularly true for children, who are delicate and susceptible to more harmful effects when exposed to sunlight than adults.

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Photo-induced skin reactions are common in reaction to essential oils, because of their strong UV absorptive capabilities. This is thought to result from the interaction of the UV light with the terpenes, ultimately creating free radical damage on both chemical and biological levels. Free radicals are known to cause a lot of damage in our bodies as they contribute to many diseases such as cancer and heart disease. The very reason why essential oils containing high amounts of terpenes are not considered safe for use is that the combination leads to even more phototoxic activities than just one compound at a time during exposure.

Essential Oils That Cause Phototoxicity:

1) Lemon Essential Oil

Lemon Essential Oil has a high resin content and is strongly phototoxic. It affects the skin both through phototoxic and photoallergic mechanisms. Skin reactions can appear as fast as 15 minutes and last for one to several weeks. Symptoms can include redness, itching, peeling, and dark spots on the skin.

2) Orange Essential Oil

Photo-induced damage is common on the skin when Orange essential oil is used in sunscreens or as a tanning agent. The most commonly seen reactions are reddening of the skin and hyperpigmentation. The essential oil contains significant amounts of alpha-pinene and linalool which are known terpenes capable of oxidizing in UVB light.

3) Tea Tree Essential Oil

Tea Tree Essential Oil is phototoxic but less strong than lemon oil. The exact mechanism is unknown, yet it may be due to interferences in the photosensitizing pathway, interference with UV absorption, or an interaction with other components in the mixture that prevents photodamage from occurring. Oils with high amounts of tea tree have been reported to have serious skin reactions in sensitive people. 

4) Grapefruit Essential Oil

There are several reports of photo-dermatitis with grapefruit oil or grapefruit seed extract. The citrus terpenes present in grapefruit are known to cause photoallergic reactions and when combined with UV light, can lead to acute phototoxic reactions.

5) Thyme Essential Oil

Thyme Essential Oil is considered photo irritant and phototoxic but less than other terpenes such as citronella. It may be due to the presence of thymol, an active ingredient responsible for its antimicrobial properties that causes a photosensitization reaction resulting in an erythematous rash in areas exposed to sun or UV light.

6) Cinnamon Leaf Essential Oil

Cinnamon Leaf essential oil is phototoxic because of its high amounts of eugenol. Eugenol is known to cause photosensitization when exposed to UV light and leads to a reddening reaction within minutes.

7) Peppermint Essential Oil

Peppermint essential oil contains small amounts of menthol, which can be phototoxic, and summer campfire antirheumatic which may lead to skin reactions. The photo-sensitization mechanism is believed to be due to the thymol present in peppermint.

What Is Phototoxicity In Essential Oils?

Phototoxicity is a chemical reaction of the skin that occurs when it absorbs UV (ultraviolet) light and reacts with the compounds of essential oil. Phototoxicity is the result of some essential oils containing compounds that absorb UV light and produce photodamage which may lead to inflammation, redness, rashes, or even burn the skin. The most common cause for phototoxic reactions is after applying an essential oil containing high amounts of terpenes like citrus, directly onto your skin without applying a base such as a vegetable or mineral oil. Applying too much sunscreen while wearing very little clothing can also be toxic.

How Can You Use Phototoxic Essential Oils In Summer?


Step 1: Make sure to always wear sunscreen with at least SPF 15. Although essential oils have photoprotective properties, the chance of burning the skin is still there. Studies propose that terpenes like linalool and alpha-pinene can both act as sunscreen ingredients when used in combination with other sun-protecting substances.

Step 2: Always apply the essential oil(s) on your body for 30 minutes before going out into direct sunlight. This will ensure that you will not burn because of the UV light exposure.

Step 3: Apply sunscreen or another form of sun protection that you feel comfortable using together with your skin care products containing essential oils. If you're not sure how to apply sunscreen, consult the label to see if it contains an SPF rating. Apply at least 30 minutes before going out into direct sunlight.

Step 4: Let the essential oil completely dry on your skin then wash it off. If you use a dry oil blend during the application, it should be washed off with warm water and gently pat dry.

Step 5: After showering or bathing, make sure that none of the essential oils are left on your skin or body as this will cause irritation and redness.

Step 6: If you have any changes in your skin or discover that essential oils have caused photoallergic reactions on your skin, please see a dermatologist to determine if you are at risk for skin cancer.

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1) What is the recommended methodology for using phototoxic essential oils?

Phototoxic oils can be used on your body and scalp after the application of a base such as a mineral or vegetable oil. After thoroughly rubbing or massaging the essential oil blend into the arms, legs, back, and scalp (avoiding the face), allow it to fully dry before washing it off with warm water. Don't rub too hard since this will cause irritation and redness in sensitive areas.

2) What is the difference between phototoxic and photosensitizing oils?

Both oils can hurt the skin but are usually used interchangeably. Phototoxic oils usually contain high amounts of terpenes (compounds that absorb UV light) like citronella and linalool. Photosensitizing oils usually contain menthol and thymol which are both capable of causing allergic reactions when the body or scalp is exposed to direct UV light. There could be exceptions to this like essential basil oil due to its high amount of linalyl acetate which is also phototoxic, but its overall photo-sensitization potential is minimal.

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