Myth No. 9 - Adding Citrus Flavours in Summer Skincare
It's easy to associate sunny summer weather with bright, citrus flavours. Lemon, lime and grapefruit are some popular choices for summer skincare. When it comes to natural skincare, essential oils are an easy way for formulators to impart these uplifting aromas into their products. Yet any experienced natural skincare formulator would recognize the dangers of using these essential oils for skincare products that may be exposed to direct sunlight after application.
Ever heard of "margarita burn"? When squeezing fresh lime juice into your cold margarita drink under the summer sun, you may actually expose your skin to second-degree burns. Sounds too serious to be true? Well, let's dive into the science behind it.
Furanocoumarin (FC) is a biological chemical compound produced by a number of citrus fruits as a self-defense mechanism against herbivore insects. They become phototoxic once exposed to UVA rays in sunlight. As it becomes absorbed into the skin via contact, it can cause redness, blisters, and burns within 24 hours of exposure. A dilution as low as 0.03% (Tisserand & Young, 2013) is sufficient to result in this skin condition, officially known as "phytophotodermatitis".
Below is a quick reference table for common essential oils and their relation to phototoxicity (Tisserand, pH. 87, 2013):
|Cold-Pressed Lime||Steam-Distilled Lime|
|Cold-Pressed Lemon||Steam-Distilled Lemon|
|Bitter Orange||Sweet Orange|
As you can see, some of the differences between phototoxic and non-phototoxic essential oils are fairly subtle, such as understanding the extraction methods of each essential oil, and it is challenging to identify by pure scent whether a citrus flavored product might contain phototoxic essential oils. As such, it is important to exercise caution when selecting day time skincare products and when in doubt, always ask the manufacturer to provide additional information about the ingredients used.