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How to test an essential oil?


It is very important to test for possible allergies or skin tolerance to essential oils before making your formula, especially if you have sensitive skin or a tendency for allergies…

scratching arm

When should you do an allergy test for an essential oil?

Each person is different regarding allergic reactions. People with very sensitive skin and those who have a tendency to often have an allergic reaction must be particularly vigilant because they are likely to be more susceptible to a reaction against essential oils.
On the other hand, the reverse is not true. It is not because you are allergic to nothing that you are protected. Some essential oils contain allergenic molecules, so yes, anyone can be allergic to an essential oil: either in a chemical compound present in the EO chosen, or because certain EO have well known negative effects (I will give you the list of those later in my article).
You won’t be allergic to an EO but to a molecule.



How do you carry out an allergy test for essential oil?

Carry out the test in the crook of your elbow!

test essential oil


The first reflex to have is to do a small skin test, somewhere discreet on the body each time you purchase a new EO.
The amount to apply need not be great. Because, contrary to a skin reaction such as an itchy or burning feeling, an allergic reaction occurs at a very low threshold, as soon as the body is in contact with what is an allergenic substance for that person.




Testing a “gentle” EO for the skin
If in the description of your new essential oil you read that it can be used pure on small areas, and if you do not have a tendency to have a skin reaction: you can test it purely by putting a drop directly in the crook of your elbow.
Testing a “dermo-caustic” EO
If you wish to test an EO known to be irritating for the skin, you must dilute it first in a few drops of VO (of your choice) before applying it to the crook of your elbow.



How can you tell if the test is positive or negative?

Do you notice a skin reaction? It was a good idea to do the test.
Leave it at that and talk to your doctor about it.
You must also note that even if the allergy is not immediate, any overuse or excessive use of EO may lead to greater sensitivity, even an allergy. The more you are exposed to the allergenic components, the more you risk becoming sensitive to them.

A few solutions to remedy the problem:

-change your EO regularly and follow the indications regarding dilutions/dosage
-avoid using them pure too often even when they are labelled “gentle to the skin” or do it for short periods of time.



Test also your “old” essential oils

Your “old” essential oils have the potential to be detrimental if they have been stored badly: if they have undergone great variations of temperature and have not been kept away from daylight or if the bottles have been opened too often.
See paragraph “storage of EO
Tea Tree essential oil is one of the ones to be wary of as soon as they are getting old as well as essential oils of citruses that are fragile and volatile.



Allergy or irritation?

If an immediate reaction occurs, it is probably not an allergy but an irritation. Which means that in any case this essential oil is probably not for you or you may need to dilute it further.

An allergic reaction occurs after some time (within 48 hours – even if you wash it will not alter the result). It becomes evident through different symptoms not necessarily localised where you applied the product.

A small chart summing up the differences between irritation or the symptoms of an allergic skin reaction :

irritation vs allergy

To ease the pain, have the VO reflex to remove an EO from the surface of the skin and slow down its penetration. Water is useless.

– in the case of skin intolerance?

The heat is bearable: don’t do anything.
It is really too hot: rub a little VO on the area. Do you still want to use it? You will have to dilute the EO in more VO.

– in the case of an allergic reaction?

If the reaction occurs immediately after contact with an EO, clean the area used for testing with a cotton bud dipped in vegetable oil.
It is always better to contact a health professional and avoid all contact with that essential oil while waiting to know where the reaction comes from. In the meantime, of course, you must not use this essential oil (not in any way, even if more diluted). If you are allergic to other EO you can check the chemical components of each oil and see if there are commonalities between them. That way, you will find which component is at fault.


A little more about allergies:

An allergy is defined as an excessive and unwanted defence reaction of the immune system when in contact with substances that are normally harmless (allergens) and are found in the air, in cosmetics, food or medication.

allergy symptoms

It manifests itself in two ways:

– The immediate allergy occurs if there is a genetic predisposition to allergies. It can be

  • respiratory (like asthma or breathing distress),
  • dermal (such as swelling of the face, lips, itches, burning feeling),
  • ocular,
  • abdominal cramps, nausea, diarrhoea and the reaction occurs from a few minutes to two to three hours after contact with the allergen.

– The delayed allergy or contact allergy can occur to anyone, even in the absence of a genetic predisposition. It will generally arise a few days later. Reactions are generally localized and arise in the form of burning, itching, redness or inflammation (most often: ingredients of some hair colouring components, preservatives, perfume, some medication applied locally…)

allergen list The European Union has defined a list of 26 allergenic substances
(this does not mean that everyone will react).

You can download it HERE



You can also download “Essential Oils and their adverse effect” HERE

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