With the warmer weather there are more individuals flocking to citrus essential oils as they clean, diffuse, and make a variety of DIY products with those oils. Only a small number of those users are aware of the potential phototoxicity risks associated with some essential oils.
Sadly, many current essential oil users view reactions from the use of essential oils as the body detoxing. This view can perpetuate the myth that all essential oils are safe for skin use in any formulation (diluted or undiluted). We will delve into that topic another day...
What is Phototoxicity?
Phototoxicity is a very real and serious concern for many essential oil users. It is the reaction that occurs between a chemical, the skin and ultraviolet light. There are several essential oils and citrus fruits that contain the chemical components which create this type of reaction.
What chemical component causes phototoxicity?
As mentioned, furanocoumarins are chemical components that have been found to be phototoxic. They can be found in fresh squeezed citrus, plants and essential oils. A few examples of furanocoumarins include bergapten and oxypeucedanin which are found in lemon essential oil3. Other essential oils that contain phototoxic components can include bergamot, grapefruit, lime, angelic root, cumin, rue, lemon and others1. See the chart below for more details regarding essential oils and phototoxicity.
When are we exposed to ultraviolet light?
Ultraviolet light can be received from tanning beds, special plant lighting and of course the sun. Even on very cloudy days an individual is exposed to ultraviolet light.
Something else to consider is that a reaction may not occur right away. It can occur within 36 to 72 hours later in the form of moderate to severe topical reactions1. Often these reactions can include moderate to severe burns, erythema and even hyperpigmentation2.
The simple notion of squeezing a fruit with these phototoxic components can create a reaction. For example, in the summer of 2014, a woman named Erika Lotterhos was squeezing limes for margaritas and noticed a reaction within days that was attributed to furanocoumarins4 found in limes. This is not the first or last time another individual has had a topical reaction to limes either5,6.
Using Phototoxic Essential Oils Safely on the Skin
I have not shared the information above to scare you from using essential oils topical, but as a caution. Essential oils can be powerful tools to assist us when we need them, but should be respected in their use.
Many essential oils that are considered phototoxic can be used safely on the skin. In fact, in Essential Oil Safety 2nd Edition, if you look up the oils listed in the chart, you will find that they each have specific dilution ratios listed for topical applications. For example, cold pressed or expressed bergamot can be used safely with under 3 drops in one ounce of carrier oil.
It is important to also note that if you are going to create a citrus blend to be used in lotions, scrubs, etc., that the total amount of citrus oils needs to be weighed in your formulation. Measuring by drops is not an accurate means of diluting your essential oils. It is an estimate so it is important to weigh them when formulating products with them.
When used individually, phototoxic essential oils can be used quite easily. The total percentage of those oils in your formulation will need to be reduced when blending more than one phototoxic essential oil for the same product. The percentage is reduced so that the total amount of furanocoumarins present between all the essentials oils are accounted for.
I suggest creating a stock blend of those oils first. Then use the stock blend versus drops of each individual oil into your topical formula to minimize the risk of phototoxicity.
Phototoxic Essential Oils & Dilution Rates
Common Name/Botanical Name %
Angelica root (Angelica archangelica L.) 0.8
Bergamot (Citrus bergamia) (cold pressed) 0.4
Bitter Orange (Citrus x aurantium L.) (cold pressed) 1.25
Grapefruit (Citrus paradisi) (cold pressed) 0.4
Lemon (Citrus limonum) (cold pressed) 2.0
Mandarin Leaf (Citrus reticulata blanco) 0.17
Rue (Ruta graveolens L.) 0.15
Not all essential oils are phototoxic!
Keep in mind, not all citrus essential oils are phototoxic either. Many of the cold pressed essential oils like bergamot, lime, lemon, and grapefruit can be steam distilled or created without furanocoumarins. Often, reputable suppliers will list these as FCF free, Bergapten free or not phototoxic. Additionally, there are some citrus oils that when cold pressed are not phototoxic. Sweet orange is one of them. Please note that sweet orange and bitter orange are not the same and have different botanical names (citrus sinensis L. versus citrus aurantium L.).
So you absolutely can use essential oils topically if you will be exposed to ultraviolet light. However, you should definitely look to see what the dilution recommendations are for each essential oil to avoid phototoxicity.
Please feel free to email me with any questions!
1 Clark, Sue. Essential Chemistry for Aromatherapy. 2nd ed. New York: Churchill Livingstone, 2008. Print.
2 Tisserand/Young. Essential Oil Safety. 2nd ed. New York: Churchill Livingstone, 2014. Print.
3 Buckeye, Jane. Clinical Aromatherapy Essential Oils in Practice. 2nd ed. New York: Churchill Livingstone, 2003. Print.
4 "Florida Woman Suffers from Burns after Making Margaritas." Yahoo News. Charlene Sakoda, 1 May 2014. Web. 7 May 2016. <https://www.yahoo.com/news/blogs/oddnews/florida-woman-suffers-from-burns-after-making-margaritas-191026427.html?ref=gs>.
5 "Some Medicines Can Make Your Skin More Sensitive to the Sun." MNT. 12 May 2015. Web. 7 May 2016. <http://www.medicalnewstoday.com/releases/287841.php?tw>.
6 Stern, Melissa. "Local Woman Finds Unlikely Combinations of Sunlight and Limes Caused Burns." Fox4KC.com. Fox4, 10 June 2015. Web. 7 May 2016. <http://fox4kc.com/2015/06/10/local-woman-finds-unlikely-combination-of-sunlight-limes-caused-burns/>.
7 Johnson, Joe. "Children Burned by Fruit Bounce Back." The Sentinel. 22 Mar. 2014. Web. 7 May 2016. <http://hanfordsentinel.com/news/local/children-burned-by-fruit-bounce-back/article_543bbb14-b155-11e3-95fc-0019bb2963f4.html>.