Carrier oils … essential oils …
Both play important roles in aromatherapy and both offer therapeutic benefits. A few of them even look the same.
But they are not the same. In fact, there's more differences between them than similarities.
Here's how the two are different.
Difference # 1: The source of extraction
Carrier oils are obtained from the “fatty” parts of plants such as the seeds, nuts or kernels.
And although there are a few exceptions such as carrot seed and fennel, the vast majority of essential oils are extracted from the aromatic parts of plants, which tend to be the flowers, leaves, stems or bark of plants.
Difference # 2: The existence of nutrients
There's a common myth that essential oils are a rich source of nutrients such as proteins, enzymes and vitamins. They are not.
Well, let's start with proteins and enzymes. Protein and enzyme molecules are too heavy to be extracted by steam distillation (which is how most essential oils are extracted). In addition, the heat from the distillation process breaks down proteins and enzymes.
For vitamins, certain vitamin molecules are too heavy to be able to be extracted via steam distillation as well. Those that are light enough can theoretically be extracted. But if so, the amounts present are so tiny that the vitamins do not even show up in the chemical analysis profiles.
Carrier oils, on the other hand, will have such nutrients in abundance if properly extracted through cold-pressing.
Difference # 3: The existence of fatty acids
Carrier oils contain fatty acids and will leave an oil stain on paper or cloth.
Essential oils do not contain fatty acids and will usually not leave stains on paper or cloth. (Note: More viscous, darker-colored ones may because of their color.)
Difference # 4: The reaction with plastic
Carrier oils are usually sold in plastic bottles. This is generally fine if they're not stored for too long.
Essential oils, however, will dissolve plastic. This is one reason why reputable sellers will never use plastic packaging. They will use glass or metal instead to avoid oil contamination.
Difference # 5: The rate of evaporation
Carrier oils are what we call fixed oils. They do not really evaporate at room temperature.
Essential oils are volatile oils. They evaporate (diffuse) at room temperature.
Difference # 6: The aroma strength
As carrier oils are extracted from the “fatty” parts of plants, they have very little aroma or at most, they will have just a slight nutty smell. If you detect a strong (and rather unpleasable) smell in your bottle of carrier oil, it probably means it has turned bad (see # 7 below).
Comparatively, essential oils are made up of volatile compounds obtained from the aromatic parts of plants. They have much stronger, and usually much more pleasant, scents.
Difference # 7: The capacity to turn bad
Carrier oils turn rancid over time. And you can easily tell that they've turned bad from the smell.
Essential oils do not turn rancid. But they do oxidize over time.
Oxidation causes all oils to gradually lose their therapeutic value and become less effective. Certain oils can also become more toxic due to oxidation.
Here, both types of oils should be properly stored and used within their shelf lives.
Difference # 8: The amount that can be safely used
Carrier oils are safe to use in much larger amounts than essential oils. This is one of the reasons why the former is used to dilute the latter.
The dilution rate guideline suggested by most sellers is about 2% for adults. This means that the essential oil should combine no more than 2% of the carrier oil volume used.
Note, however that the appropriate dilution rate will be lower for children.
The 2% rate also asserts you're diluting a single essential oil in a carrier oil. If you dilute two or more instead, the suggested dilution rate may be lower than 2%, depending on whether the oils have similar chemical components.