An important topic when summer is approaching! Indeed some essential oils must not be used in products aimed at being applied to the skin before we are about to go in the sun in the following hours. These essences react to sunlight and can leave some skin blemishes: this is photo-sensitivity.
What is photo-sensitivity?
Photo-sensitivity occurs when there is an increase of skin sensitivity to sunlight (UV rays) following the absorption or application of some chemical or vegetable substances known as “photo-sensitive”. When the skin is exposed to sunrays or other sources of UV rays (tanning lamps for example), these substances are activated and cause an irritation, sometimes a toxic one. Various skin reactions may occur: rashes, blisters, redness and light or dark brown blemishes, or an irreversible depigmentation.
As far as the “invisible” aspect is concerned, this can sometimes become dangerous given that such a reaction to sunrays causes modifications to the epidermis that can promote skin cancer…
These substances are found in all essences that contain furocoumarins (for example bergapten or psoralen) and/or psoralens, as well as methyl anthranilate which is found in citrus essences but also in some EO. The photo-sensitivity reaction varies between individuals.
The time needed to eliminate the risk is not clear as yet. It can vary between 6 and 12 hours depending on the EO, the sun strength and the time of exposure…
Precautions of usage
It is recommended to avoid exposure to UV rays at least 12 hours after the application or ingestion of photo-sensitive EO or a preparation containing some.
It is, therefore, safer to use one at night or to choose using it in winter when exposure to UV rays is less likely.
IFRA (International Fragrance Association) is an institution in charge of assuring the safety of raw materials in perfumery and more specifically to list all EO likely to cause skin reactions as well as fixing the rules concerning their usage.
- Angelica root: 0.8%
- Bergamot: 0.4%
- Lime: 0.7%
- Lemon zest: 2%
- Cumin: 0.4%
- Mandarin leaf: 0.17%
- Bitter orange: 1.25%
- Grapefruit zest: 4%
- Marigold: 0.01%
Here is a list of the most common essences and essential oils concerned (not exhaustive)
EO of the Citrus family (Rutaceae) extracted from zest:
Bergamot (Citrus aurantium ssp bergamia op zest) – toning, deodorising and stimulating. It must never be applied to the skin.
Bitter orange (Citrus aurantium ssp aurantium op zest)
Lemon (citrus liminum) or Lime (citrus limetta op zest) – antibacterial qualities
Grapefruit (citrus paradisii op zest) – brings good mood and works well as an aerial antiseptic.
Cedrat (citrus medica) – very effective expectorant
Combawa (citrus hystrix) – fights stress and insomnia.
- Khella (Ammni visnaga)- antispasmodic, dilates the bronchi (asthma attacks)
- Angelica seeds – root (Angelica archangelica)- anti-stress and sedative.
- Celery (Apium graveolens)- soothes cystitis, gout, arthritis…
- Verbena (Lippia citriodora)- sedative and anti-inflammatory. It must never be applied to the skin
- Cumin (Cuminum cyminum)- digestion discomfort
- Carvi (carum carvi) – helps digestion, fights flatulence
- Fennel (foeniculum vulgare)- diminishes menopausal problems
- Dill (anethum graveolens)- eases bloating
- Carrot (daucus carota)- fights brown blemishes
- Lovage (levisticum officinale) : Very good for poison control, it is antitoxic and detoxifying. Lovage is also antibacterial, antifungal and anti-parasitic. It is widely used to treat psoriasis.
Non-exhaustive list !!! Do not forget that although this is not an EO, Hypericum (Hypericum perforatum) is also photo-sensitive.
Good to know: Photo-sensitive EO lightens your hair colour.
Non Photo-sensitive EO
On the other hand, Petit-Grain and Neroli, who are both extracted from citrus leaves, not zests, are not concerned with this problem of photo-sensitivity because they do not contain furocoumarins. They can, therefore, be used internally and externally while being exposed to sunrays.
The following EO are extracted from either the zest or the leaves of rutaceae but they are not photo-sensitive:
Source: Essential Oil safety Tisserand/Young
- Bergamot without bergapten/furocoumarins (Citrus aurantium)
- Lemon distilled by water vapour (Citrus limonum)
- Lemon leaves
- Lime distilled by water vapour
- Mandarin zest pressed (Citrus reticulata)
- Sweet orange zest pressed (Citrus sinensis)
- Sweet orange leaves
- Yuzu (Citrus junos)
So ladies, this summer:
Avoid concocting anti-cellulite massage oils containing grapefruit before going to the beach (keep the grapefruit for winter)…
Forget lemon verbena, citrus essences or angelica on your skin in the morning or in the daytime. No Hypericum either.
In short, in summer, only use citrus EO at night! On the other hand, diffusion is always a possibility.