What Are Phototoxic Essential Oils and How Can I Use Them?

Summer’s finally here and that means longer daylight hours, which means more time outside and more exposure to the sun. So, of course, we’re quick to protect ourselves from the sun’s UV rays by applying sunscreen, but I want to talk to you about how important it is to also protect your skin from certain essential oils when you’re out in the sun.

The oils I’m going to be talking about are wonderful essential oils and can be enjoyed for many different intentions. But at certain dosages, and in combination with skin and sun, there are a few precautions you need to take.

LET’S TALK ABOUT THE TERM PHOTOTOXICITY

Phototoxicity, also sometimes referred to as photosensitization, is a light-induced reaction to a substance that is photoactive. So, in this case, the essential oil is the photoactive substance and the sun’s UV rays are the light. The reaction occurs when the essential oil on the skin is “activated” by the light. It can cause blistering, burning and even discoloration of the skin.

An essential oil is said to be “phototoxic” when it increases the likelihood of a phototoxic reaction.

SO, WHAT MAKES AN ESSENTIAL OIL A PHOTOTOXIC SUBSTANCE?

All essential oils are a collection of chemical compounds, but it’s the essential oils with a particular chemical component, for example furanocoumarins (FCs), that make them photoactive. And while not all FCs are phototoxic, there are a few to watch out for like psoralen, methoxsalen, bergapten, and oxypeucedanin. These molecules have a structure that allows them to absorb the UV light, store it and then release it in a burst into the skin.

THE EXTRACTION METHOD IS IMPORTANT

Knowing how your essential oil was extracted from the plant part is critical because the chemical component(s) that can cause phototoxicity may be in the plant itself, but are not always in the final distilled/expressed essential oil. For example, several citrus essential oils are considered phototoxic, but it’s the method in which the essential oil was distilled that determines if it is, in fact, reactionary.

COMMON PHOTOTOXIC ESSENTIAL OILS

The below is not an exhaustive list. I recommend you read Robert Tisserand and Robert Young Essential Oil Safety for more detailed information, but here’s a list of the most common phototoxic essential oils:

Angelica Root Angelica archangelica

Bergamot Citrus bergamia (Cold-pressed)

Bitter Orange Citrus aurantium (Cold-pressed)

Cumin Cuminum cyminum (Steam distilled)

Grapefruit Citrus paradisi (Cold-pressed)

Key Lime Citrus x aurantifolia var. swingle (Cold-pressed)

Lemon Citrus limon (Cold-pressed)

Lemon Verbena Lippia javanica (Steam distilled)

Lime Citrus aurantifolia (Cold-pressed)

THE FACTORS THAT DETERMINE IF A PHOTOTOXIC REACTION TAKES PLACE

DILUTION

Whether using a single essential oil or a blend of several oils, it’s the total % of essential oil in the skin application (lotion, massage oil, body butter, etc.) that you need to be mindful of. It’s the calculation of the % of furanocoumarins in the total amount of essential oil that determines the risk. The risk of phototoxicity increases if you're putting several oils with photosensitizing properties in one blend.

DOSE

This is the amount of the final product you are applying on your skin. The larger the quantity of product, and the more often it is applied on skin, helps determines the severity of the reaction.

TIME

This is the amount of time between application and sun exposure. Taking a quick walk from the car to the grocery store is not enough sun exposure to have an effect. But if you’re taking a long walk on the beach or working in your garden that could be enough exposure.

SIGNS OF A PHOTOTOXIC REACTION

Phototoxic reactions can happen 18 - 72 hours after the essential oil is applied to the skin and then exposed to UV sunlight. The most common reaction is a strong sunburn and blistering. However, more serious reddening of the skin can also occur and can peak 36-72 hours after UV exposure, along with more intense swelling with marked skin discoloration which can last for months.

YOU CAN MAKE BLENDS WITH PHOTOTOXIC ESSENTIAL OILS… IN MODERATION

The good news is, if you minimize the exposure, you can still use phototoxic essential oils safely on skin. Here are a few examples:

Bergamot Citrus bergamia: 2 drops per 1 ounce (30 ml) of carrier oil

Lemon Citrus limon (cold pressed): 12 drops per 1 ounce (30 ml) of carrier oil

Grapefruit Citrus paradisi (cold pressed): 24 drops per 1 ounce (30 ml) of carrier oil

Lime Citrus aurantifolia (cold pressed): 4 drops per 1 ounce (30 ml) of carrier oil

Bitter Orange Citrus aurantium (cold pressed): 8 drops per 1 ounce (30 ml) of carrier oil

ENJOY THE OILS… JUST BE MINDFUL OF THE SUN

I encourage you to use these wonderful essential oils, especially the bright citrus oils great for that fresh summer feeling. Just be mindful of the sun. If you apply the blend to an area covered by clothing and then go out in the sun, you should be fine. The phototoxic reaction only occurs if the blend is applied to sun-exposed skin.

CITRUS ESSENTIAL OILS THAT ARE NOT PHOTOTOXIC

There is a misconception that all citrus oils are phototoxic. The citrus oils below are not phototoxic so use away! Just be mindful of the expression method.

Lime Citrus aurantifolia (distilled)

Lemon Citrus limon (distilled)

Sweet Orange Citrus sinensis (cold pressed)

Mandarin Citrus reticulata (cold pressed)

Tangerine Citrus reticulata (cold pressed)

If you’re still unsure about using phototoxic essential oils, just avoid using them topically on skin. You can still enjoy them via diffusion and personal inhalation. But overall, with a little mindfulness and safety in mind, all essential oils can be a wonderful and beneficial addition to a healthy summer lifestyle.