If you frequently use essential oils on your skin, then applying some of them topically in the summertime might pose a challenge. This is because some essential oils may cause a reaction when the skin is exposed to sunlight. Such reactions are known as phototoxicity. But, with the proper precautions, you can still enjoy the benefits of these oils during the summer months.

What is Phototoxicity?

Phototoxicity occurs when compounds called furanocoumarins (which are found in certain essential oils) react to UV rays, causing an inflammatory response in the skin (source). Phototoxic reactions commonly result in severe redness/sunburn, darkening of the skin, edema (swelling), and sometimes even blistering. The visible signs of phototoxicity generally peak about three days after UV exposure, but they can last for weeks.

Which Essential Oils are Phototoxic?

As I mentioned above, essential oils that contain furanocoumarins are generally considered to be phototoxic. The citrus oils as a group are often put in this category. However, there are exceptions to every rule. For example, sweet orange and blood orange oils are not phototoxic, while bitter orange is. 

The method by which essential oils are extracted from the plant also affects whether or not a citrus oil exhibits phototoxic properties; cold pressed lemon and lime essential oils are phototoxic, but the steam-distilled versions are not. This is because the furanocoumarin molecules in lemon and lime essential oils are not volatile and therefore remain behind during steam distillation. When the oils are removed by cold pressing the peel of the fruit, the furanocoumarins are retained in the essential oil. (Our lemon and lime essential oils are cold-pressed; however, there are several ways to prevent reactions to sunlight when using them topically. Read on to learn more.) The following is a partial list of essential oils that can be phototoxic and should be used with caution if you’re going to be exposed to sunlight.

• Angelica Root
• Bergamot
• Bitter Orange
• Grapefruit
• Lemon- cold pressed
• Lime- cold pressed
• Mandarin Leaf
• Rue

Oils that are generally considered to be safe in the sun include:

• Bergamot- steam distilled (furanocoumarin-free)
• Blood Orange
• Lemon- steam distilled
• Lime- steam distilled
• Mandarin
• Sweet Orange
• Tangerine

For more complete lists, see AromaWeb’s article on Phototoxicity and Essential Oils.

Guidelines for Using Phototoxic Essential Oils

There are several precautions that can be taken when using phototoxic essential oils. Avoiding direct sunlight (and tanning beds) for 12 to 24 hours after applying phototoxic oils to the skin is often recommended (source, source). Wearing clothing that covers the areas where the essential oil was applied is also helpful. Just be aware, though, that thin materials and fabrics may not provide sufficient protection.

Diluting phototoxic essential oils with a carrier oil is also key to preventing a reaction. With proper dilution, essential oils considered phototoxic can still be used before exposure to sunlight. The following chart provides guidelines for diluting a few common phototoxic oils:

Essential Oil                           Drops Allowed per 1 Ounce of Carrier Oil 

Bergamot                                                               1

Bitter Orange                                                          8

Grapefruit                                                              24

Lemon (cold pressed)                                             12

Lime (cold pressed)                                                 4

If you are new to essential oils or to citrus oils, dilute them properly, and test out them on a very small area of skin before going out in the sun. If no reaction occurs, you can try using them on larger areas.

Many skin care products contain citrus essential oils, but many of them are still safe to use and likely will not cause a reaction in the sun. Products that are washed off of the skin after use- such as soaps and shampoos- generally do not cause reactions (source). Some Verefina products contain citrus essential oils, but all of them are in concentrations that make them safe for application before sun exposure. 

Some drugs, including tetracycline, may increase the skin’s sensitivity to the sun; using phototoxic essential oils in combination with such drugs may further increase sensitivity to UV rays (source).

When using essential oils, it is important to be aware that some of them may cause a phototoxic reaction. However, avoiding direct sunlight after application, wearing protective clothing, and diluting your oils well can all help prevent adverse reactions and allow you to enjoy the benefits of these oils year round.

Sources:

Harris, Lea. “Phototoxic Essential Oils- Which Ones to Avoid When Out in the Sun.” Using Essential Oils Safely. 22 April 2015. Web. 1 June 2016.

http://www.usingeossafely.com/phototoxic-essential-oils-which-ones-to-avoid-when-out-in-the-sun/

Naganuma, M; Hirose, S; Nakayama Y; Nakajima K; Someya T. “A Study of the Phototoxicity of Lemon Oil.” PubMed. Web. 1 June 2016.

http://www.ncbi.nlm.nih.gov/pubmed/4096528

“Phototoxicity and Essential Oils.” AromaWeb. Web. 1 June 2016.

http://www.aromaweb.com/articles/phototoxicity-essential-oils.asp

“Safety Information.” National Association for Holistic Aromatherapy. Web. 1 June 2016.

https://www.naha.org/explore-aromatherapy/safety/

About the Author

Katie Zapotoczny is a Verefina Affiliate and the creator of An Ever Green Life, a blog that seeks to empower readers to make changes that will improve their health and help protect our environment.