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Essential oils basics

Back in 2016, I gave a conference about uses of essential oils for chronic pain, injuries and inflammation. But before trying to explain what I knew, I needed to understand people's view on aromatherapy, especially in the sport field. So, I created a survey, shared it and waited for answers. Fifty-one person took that survey and this is what I got:


(I've got one interesting comment "sounds like bullshit".)

So most of athletes questioned knew about aromatherapy ... but were not using it ... why? 

I had to ask them to find out.

« If there is sufficient scientific evidence for treatment with plants, then yes I am interested »

« Many articles argue that phytotherapy is either a placebo or a wonderful cure for everything. It's hard to have an objective opinion on the subject. »

« I was once given a comfrey and cayenne cream by an herbalist for a muscle overuse injury but discontinued the applications beacuse i was worried about disrupting my "natural" pain signals.»

Interestingly people thought they knew about essential oils but were full of misconceptions or doubts regarding theirs efficiency. 


Aromatherapy is the use of essential oils (EO) for therapeutic purposes.

Essential oils are the result of a process called DISTILLATION. Distillation is a separation process. In short, volatile essences are extracted from aromatic plants. It takes a huge amount of fresh plants to produce the 5 or 15ml of EO you will buy and of course plants with less volatile componds will be more expensive. As an example "it requires 6,000 pounds of melissa plant to distill just a single pound of melissa essential oil."

It is hence not a whole natural product in the sense that EO are VERY CONCENTRATED and VERY POWERFUL. This is very important to remember : it is not because a product comes from a plants that is cannot be dangerous.


Some people apply EO without any dilution. THIS IS WRONG. 

Some people think they can put EO in their eyes. THIS IS WRONG.

Some people add a few drop of EO in their water or in their coffee. THIS IS WRONG.


As their names suggest essential OILS are lipophilic which means they cannot be diluted in WATER. They are hydrophobic.

EO must be diluted in a vegetable oil. They need a carrier unless you are doing an inhalation. Then yes, you can definitively use them for (non-)therapeuthic purposes.

There are three common ways for absorption:

  1. Skin : when you are getting a massage with EO or when you apply an oitment
  2. Inhalation or Diffusion 
  3. Internal : which can be either swallowed or absorpbed through vaginal or rectum suppositoire
When apply on the skin EO compounds travel through the membrane through a process called diffusion before reaching the bloodstream. It is important to remember that:

  • EO compounds can load up in fat tissus since they are fat soluble, then can be release slowly in time
  • EO compounds are very volatiles
  • Skin thickness can vary in different part of the body and so absorption will vary too
  • ~10 or less% will actually reach the bloodstream
  • To be efficient we want them where we need them
  • There is a huge variabiliy of EO compounds entering the bloodstream and hence huge variability in plasma concentration between person, due to metabolism, hydration of the skin, temperature, amount of fat vs muscle etc

Inhalation is much stronger than diffusion since it is usually at higher concentration. Diffusion is mostly use to give a pleasant smell in a room while inhalation have more of a therapeuthic purpose. Smelling EO is an interesting choice since EO compounds will reach the bloodstream through the respiratory system but also bound with olfactory gland. Olfactory nerves and fibers will then transmit information to the brain. 

Finally internal use of EO requires A LOT OF precautions. In the world of aromatherapist some will argue that EO cannot and shouldn't be ingested for any reasons. Some will use it only for culinary taste (so very small concentration) and other will use it for therapeutic reasons (hence higher concentration). The internal uses of EO also differs strongly from countries to countries and I personally do not recommend internal use of EO for people unless they know exactly what they are doing or they have been talking with a certified aromatherapist.


Because one essential oil can have has much as 100ish different chemical compounds. Hence, one EO isn’t equal to one compound and to one biological effect. Also, one plant can have different varieties ... like lavender that has approximatly 40 differents varieties or mint that has around 20 or eucalyptus that has over seven hundred differents species. The composition of an EO will vary depending on the plant, the variety, the climate where the plants has grown, the amount of precipitation during the year, etc. Which means that where your EO comes from matters a lot.

If your friend or your dad or your mom tells you "eucalyptus is great for cough" you now understand why this statement doesn't make any sense. Which eucalyptus? globulus? radiata? citriodora? polybractea ct cineol? camaldulensis?

Dr Petra Ratajc, biologist and researcher,  explains that there is approximately 37,2 trillion cells in the body. So in theory how much melecule could be in a drop of EO? She found that theoretically there are ~132 quintillion molecules of limonene in 30miligrams (~1 drop) of an EO. 

JUST SAYIN’ ~132 quintillion molecules in one drop. BE CAREFUL. 

Remember this was an 'ideal' calcul to know of how much molecules could be in one drop of EO. Dr Petra Ratajc chose to calculate it with limonene so this is not how much limonene you actually find in EO. Her point was that if ALL chemical compounds of an EO could enter the circulation (which means 100% of absorption) then we would have 4 million of molecules/cell (!). 

Now to put that into perspective she also explains that we have more that 40 million of proteins per cell hence a ratio 4/40 = 0,1. Also, it is not because a compound reach a cell that it will have an effect. 

Oh and also, 100% absorption is impossible, unless doing intravenous. 

Of course chemical compounds of essential oils are neither all known nor had been studied science. Science does explain a lot of how and why EO compounds work in our body, but there is also an extensive 'traditional' and 'empirical' knowledge of the use of EO.

That is why you should learn about EO before using them randomly.

I never stop learning and I did quite a lot of research to write this, so I hope you enjoyed reading this and that you've learn quite a few things.