Photo Toxic Essential Oils

Definition and Identification of Photo Sensitive Aromatic Oils

Sep 22, 2008

Some essential oils are photo toxic; defining photo sensitivity and establishing aromatic oils to use with care can help eliminate any potential misuse in aromatherapy.

Photo toxicity, also known as photo sensitivity, is essentially being more responsive to light, due to the presence of a radiation-absorbing substance, such as sunlight; in humans, it is thought that the presence of the chemical element furanocoumarins is responsible for this reaction. Certain essential oils contain this chemical and therefore increase a person's possibility of having a response to sunlight, and thus increasing the risk of sunburn.

Furanocoumarins are a close relative of coumarins, another chemical element present in the make-up of some essential oils. The most notable example of a furanocoumarin in essential oils is Bergaptene which is naturally found in the essential oil of Bergamot (citrus bergamia). Bergaptene used to be added to sunscreen lotions to aid tanning, although this practice is no longer continued as it caused sunburn to those with sensitive skin or uneven tanning.

Bergamot Essential Oil

Bergamot (citrus bergamia) is the most notable photo toxic essential oil; there are now some Bergamot essential oils which are 'Bergaptene-free' to try to avoid the potential photo sensitivity risk. Bergamot has been the focus of several scientific studies in the search to establish its 'risk potential' when used in both aromatherapy and for perfumery purposes.

Studies include Zaynoun S T, Johnson B E and Frain-Bell W (1977) – A Study of Bergamot and its Importance as a Photo Toxic Agent, and Pathak M A, Fitzpatrick T B (1959) – Relation of Molecular Configuration to the Furocoumarins which Increase the Cutaneous Responses Following Long Wave Ultraviolet Radiation.

Photo Sensitive Essential Oils

Some essential oils contain up to 2% furanocoumarins, most notably those of expressed citrus oils. Although it is commonly believed that all citrus oils are photo toxic, this is not necessarily the case; for example Sweet Orange (citrus sinensis), (as opposed to Bitter Orange (citrus aurantium var amara) which is photo sensitive), Grapefruit (citrus paradisi) and Mandarin (citrus reticulata). Other essential oils which are considered to be photo toxic and therefore should be used with care in aromatherapy include:

When using these essential oils care should be taken to avoid exposure to sunlight, ultraviolet light and sun beds after application; pure Bergamot essential oil, when diluted in a carrier oil, is considered to be safely absorbed by the bloodstream two hours after application, although opinions vary as to the exposure period for other essential oils.

References:

Lawless, Julia 1995 The Illustrated Encyclopedia of Essential Oils London: Element

Price, Shirley, Price, Len 1999 Aromatherapy for Health Professionals Edinburgh: Churchill Livingstone

The copyright of the article Photo Toxic Essential Oils in Aromatherapy is owned by Sharon Falsetto. Permission to republish Photo Toxic Essential Oils in print or online must be granted by the author in writing.