Topical application and dilution of essential oils

How to dilute essential oil

At some point in time you will come across the quote “If it’s on your skin it’s in your body”.

This is very true, however the method a substance uses to enters the body changes the effect and potency. First I’ll cover topical because I have been writing about essential oils.

There are some very popular companies that encourage customers to ingest their oils. This should never be done without the direct supervision of a licensed professional. Most oils have the potential to do great harm, though some can be ingested with little risk, it still needs to be done with direction and professional education.

To understand the basic process here is a quoted section of a wikipedia article (full link below):

“To be absorbed through the skin, a chemical must pass through the epidermis, glands, or hair follicles. Sweat glands and hair follicles make up about 0.1 to 1.0 percent of the total skin surface.[2] Though small amounts of chemicals may enter the body rapidly though the glands or hair follicles, they are primarily absorbed through the epidermis. Chemicals must pass through the seven cell layers of epidermis before entering the dermis where they can enter the bloodstream or lymph and circulate to other areas of the body. Toxins and toxicants can move through the layers by passive diffusion. The stratum corneum is the outermost layer of the epidermis and the rate-limiting barrier in absorption of an agent.[3] Thus, how quickly something passes through this thicker outer layer determines the overall absorption. The stratum corneum is primarily composed of lipophilic cholesterol, cholesterol esters and ceramides. Thus lipid soluble chemicals make it through the layer and into the circulation faster, however nearly all molecules penetrate it to some minimal degree.[4] “

And per the CDC:

“Dermal absorption is the transport of a chemical from the outer surface of the skin both into the skin and into the body. Studies show that absorption of chemicals through the skin can occur without being noticed by the worker, and in some cases, may represent the most significant exposure pathway. Many commonly used chemicals in the workplace could potentially result in systemic toxicity if they penetrate through the skin (i.e. pesticides, organic solvents). These chemicals enter the bloodstream and cause health problems away from the site of entry.

The rate of dermal absorption depends largely on the outer layer of the skin called the stratum corneum(SC). The SC serves an important barrier function by keeping molecules from passing into and out of the skin, thus protecting the lower layers of skin. The extent of absorption is dependent on the following factors:

  • Skin integrity (damaged vs. intact)
  • Location of exposure (thickness and water content of stratum corneum; skin temperature)
  • Physical and chemical properties of the hazardous substance
  • Concentration of a chemical on the skin surface
  • Duration of exposure
  • The surface area of skin exposed to a hazardous substance

Research has revealed that skin absorption occurs via diffusion, the process whereby molecules spread from areas of high concentration to areas of low concentration. Three mechanisms by which chemicals diffuse into the skin have been proposed:

  1. Intercellular lipid pathway (Figure 1)
  2. Transcellular permeation (Figure 2)
  3. Through the appendages (Figure 3)

Figure 1: Intercellular lipid pathway

As shown in Figure 1, the stratum corneum consists of cells known as corneocytes. The spaces between the corneocytes are filled with substances such as fats, oils, or waxes known as lipids. Some chemicals can penetrate through these lipid-filled intercellular spaces through diffusion.

Figure 2: Transcellular permeation

As shown in Figure 2, another pathway for chemicals to be absorbed into and through the skin is transcellular, or cell-to-cell, permeation whereby molecules diffuse directly through the corneocytes.

Figure 3: Through the appendages (hair follicles, glands)

As shown in Figure 3, the third pathway for diffusion of chemicals into and through the skin is skin appendages (i.e., hair follicles and glands). This pathway is usually insignificant because the surface area of the appendages is very small compared to the total skin area. However, very slowly permeating chemicals may employ this pathway during the initial stage of absorption.”

Because of this a great deal of thought must be put in to prevent problems from the chemicals we put on ourselves. Essential oils are extremely concentrated and thus must be diluted. And some of them are phototoxic and many others will cause chemical burns.

Absorption can be used on purpose to get something into the bloodstream or lymphatic system. For instance peppermint oil has a special effect on the fluids in the joints and can be used to get a helpful medicine into a stiff knee, or just simply help the fluids get flushed.

Or things like aloe vera to repair sun damage. Examples of bad absorption would include many of our personal grooming products like deodorant, which typically contains aluminium. Yay! Cancer! At least your not smelly.

Don’t forget that a mucus membranes also absorb what is placed on them but at a faster rate.

The link below is a good slide show explaining the physiology inside the nose.


“This large mucosal surface covered with a rich vascular bed of highly permeable capillaries creates an opportunity for intranasal medication delivery. Not only will fluids cross the capillary bed into the air stream to humidify the air, but fluids delivered in the air stream onto the mucosa will also cross the capillary bed into the bloodstream.[1-3] For this reason, when medications of proper concentration and molecular character are delivered onto the nasal mucosa, they are rapidly transported into the capillary bed and delivered to the patient’s circulation. (See diagram comparing nasal morphine plasma concentrations to those of intramuscular and oral morphine).”

This needs to be taken into consideration when considering vapor therapy as an option for relieving symptoms of illness for babies, children, pregnant women, and others with important risk factors like seizures. As with anything, do your research carefully .

For some reason diluting essential oils can be contentious depending on who you talk to. There are different companies who will claim their oils are so pure that you don’t need to dilute them… This is patently false, safety profiles for various oils are based off of a pure essential oil in the first place. Dilution is good practice for multiple reasons. The first and in my opinion most important reason is safety. Popular oils like oil of oregano are very hot and can cause burns with relative ease. You can also develop a sensitivity to an oil from overuse. Essential oils can be be very drying to the skin, and up to 95% of an essential oil will evaporate before being absorbed. The concentration level of the oils makes it difficult for our skin to take it all in. By diluting you are practicing safe usage, using them more effectively, and saving money because your oils last longer. Robert Tisserand is considered a top expert with decades of research and experience with oils, he gave an in-depth interview covering various topics. You can read the transcript here. There are occasions to make spot applications of an undiluted oil but we won’t cover that in this article.
To dilute an essential oil (EO for the rest of the article) you need a carrier oil. A carrier oil can technically be almost anything, even cooking oil in a pinch. Better options would be coconut oil, olive oil, jojoba oil is the single best option because it never goes rancid and is very similar to our own natural skin oils. It is also important to point out that oil and water do not mix, no amount of water can be used to dilute an oil. gives one of the definitions of dilution as;

“to reduce the strength, force…..”

By using another oil you make an solution (technical meaning) which is defined by a medical dictionary as;

“a homogeneous mixture of one or more substances (solutes) dispersed molecularly in a sufficient quantity of dissolving medium (solvent).”

In this situation the carrier oil can be viewed as the solvent.

Below is a basic chart:

essential oil use chart

It is essential (pun!) to keep in mind that if you make a blend of multiple oils the dilution ratio applies to the TOTAL number of drops, not each individual oil in the blend. To store any extra diluted oils and/or blends I would encourage the reader to collect small glass jars that have lids. Make sure to label those jars so you know exactly what is in them. I’ve made many a blend and failed to label them…. I never did recall what I put in them.
As I mentioned earlier you can develop sensitivities due to overuse and/or lack of dilution. Certain oils go through chemical changes while being absorbed through the skin and can cause full allergic reactions. I’ll avoid the super technical stuff here but if you want to go over it I encourage you to read the interview (or listen) linked above. To see how common a reaction can be this video may help.

Unfortunately many will believe or be told that the skin reaction is “detox”. This is not possible because detoxing occurs from the inside out. The kidneys and liver filter toxins out of the body and yes it can come directly through the skin. A viral rash is an example of this, after the body defeats the virus it expels the dead virus and white blood cells through the skin, causing a rash. However that is still a process that starts from the inside. Skin reactions can be very mild to very serious and requiring medical attention. In children the risk is of course higher due to their age, weight, and softer skin. Why is their weight a factor? Because you can develop more systemic issues that take much longer to be noticed. The higher the weight, the more body fluids there are to dilute the compounds that were absorbed and lower the risk of slower moving systemic issues from overuse. Safe usage is good usage.

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