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Quels sont les dangers des huiles essentielles ?

Are there any dangers in the use of essential oils?

Essential oils are concentrated substances that contain powerful aromatic molecules. Thanks to their structures and activities, they are able to calm many skin disorders. However, even when applied topically, they can sometimes be harmful to the skin and even the body.

Which essential oils can cause allergies?

Many essential oils contain potentially allergenic or hyper-sensitizing molecules such as limonene, linalool, geraniol or citrals.

Although the risk of allergy depends on one's allergic background, it is essential to perform a skin tolerance test on the elbow or wrist with the essential oil in question. In addition, repeated and prolonged use of the same essential oil promotes an allergic reaction, so remember to take breaks during use.

Here is a list of essential oils containing allergenic molecules in significant quantities: dill, angelica, bergamot, bergamot without bergapten, cajeput, cinnamon (bark), lemon, clove, coriander seed, rose geranium, fragrant inula, noble laurel, lemongrass, green tangerine, lemon balm, lemon myrtle, sweet orange, compact oregano, Spanish oregano, palmarosa, grapefruit, turpentine, exotic verbena, fragrant verbena.

Some essential oils can be dangerous during pregnancy.

During the first trimester of pregnancy, essential oils should be avoided, whether taken orally or applied on the skin. Some should be avoided during the whole pregnancy while others may be used after the first 4 months.

The first risk is related to the neurotoxic potential of certain essential oils and more particularly the ketones they contain. These compounds can cause nervous or respiratory spasms as well as nausea which can increase the risk of miscarriage. Moreover, it is possible that the active ingredients present in essential oils cross the skin barrier as well as the placenta, affecting the developing embryo.

The dermocaustic potential of certain essential oils.

A compound is said dermocaustic when it causes irritations or even burns on the skin and the mucous membranes.

The molecules involved in this type of reaction are most often carvacrol (essential oil of oregano, savory, thyme), thymol (essential oil of thyme and ajowan), or aromatic aldehydes that can be found en masse in cinnamon essential oil.

To use a skin-sensitive essential oil, it should always be mixed with a carrier or vector vegetable oil and applied only to the localized areas.

Photosensitizing essential oils.

A photosensitizing substance makes the skin ultra-sensitive to solar radiation, resulting in a skin rash in the form of redness. The photosensitizing molecules present in certain essential oils are coumarin.

The following essential oils are not recommended before exposure to the sun: angelica, bergamot, chamomile matricaria, cinnamon (bark), lemon, sweet fennel, khella, lovage, green tangerine, sweet orange, grapefruit, sweet verbena.

Sources :

  • FAUCON M. Traité d'aromathérapie scientifique et médicale - Les huiles essentielles - Fondements et aides à la prescription (2017).

  • Charie, T. Se soigner par les huiles essentielles. Pourquoi et comment ça marche ? Editions du Rocher. (2019).


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