What is a CARRIER OIL?
A carrier oil is a vegetable oil derived from the fatty portion of a plant, usually from the seeds, kernels or the nuts. If applied to the skin undiluted, essential oils, absolutes, CO2s and other concentrated aromatics can cause severe irritation or reactions in some individuals. Carrier oils are used to dilute essential and other oils prior to application. They CARRY the essential oil onto the skin.
Essential Oils vs. Carrier Oils
Essential oils are distilled from the leaves, bark, roots and other aromatic portions of a botanical. Essential oils evaporate and have a concentrated aroma. Carrier oils, on the other hand, are pressed from the fatty portions (seeds, nuts, kernels) and do not evaporate or impart their aroma as strongly as essential oils. Carrier oils can go rancid over time, but essential oils do not. Instead, essential oils "oxidize" and lose their therapeutic benefits, but they don't go rancid.
Vegetable Oils/Fixed Oils/Base Oils
The term carrier oil is generally limited to use within the practice of aromatherapy. In natural skin care, carrier oils are typically referred to as vegetable oils, fixed oils or base oils. Not all fixed oils/base oils are vegetable oils. Emu oil (from the emu bird) and fish (marine) oils are also classified as fixed/base oils, but these animal-based oils are generally not used for aromatherapy work.
The Aroma of Carrier Oils
Some carrier oils are odorless, but generally speaking, most have a faintly sweet, nutty aroma. If you come across a carrier oil that has a strong, bitter aroma, the carrier oil may have gone rancid.
Examples of vegetable oils that are used as a carrier in aromatherapy:
Organic Sweet Almond Oil, Organic Apricot Kernel Oil, Organic Macadamia Nut Oil, Organic Avocado Oil, Organic Olive Oil, Organic Fractionated Coconut Oil, Organic Rose Hip Oil, Organic Grapeseed Oil, Hazelnut Oil Sesame Oil, Organic Hemp Seed Oil, Organic Sunflower Oil, Organic Jojoba oil and Organic Watermelon Seed Oil.
Avoid Mineral Oil
Mineral oil and petroleum jelly are byproducts of petroleum production. They are not of natural, botanical origin and are not used within the scope of holistic aromatherapy. Mineral oil is used in baby oils and many commercially available moisturizers because it is an inexpensive oil to manufacture. It, however, can clog pores, prevent the skin from breathing naturally, prevent essential oil absorption, prevent toxins from leaving the body through the natural process of sweating, and I've read reports that it can be absorbed into the body and block vitamins from properly being utilized. These same concerns apply to petroleum jelly.
Storing Carrier Oils
For fragile carrier oils or for those that you will be keeping for a long duration, store them in dark glass bottles with tight fitting tops, and store them in a cool, dark location.
Most carrier oils can be stored in the refrigerator, and this can help prolong the lifespan of fragile oils like Borage Seed Oil. Avocado Oil, however, should not be stored in the refrigerator. Oils stored in the refrigerator may solidify or turn cloudy and will need time to return to room temperature prior to use.
Carrier Oils and Rancidity
Essential oils do not go rancid. Carrier oils, however, do become rancid over time. The level of natural fatty acids, tocopherols, method of extraction and other characteristics of an oil all can affect how quickly an oil becomes rancid. If you come across a carrier oil that has a strong, bitter aroma, the carrier oil may have gone rancid. If you can, compare the aroma of the oil that you suspect is rancid with the same botanical oil that you know is fresh.
NVO Carrier oils are natural and unadulterated as these are the preferred situations for carrier oils. Exceptions include buying carrier oils that have natural Vitamin E added. Vitamin E, often listed as tocopherols acts as a natural preservative.
Vegetable Butters and Other Ingredients As Carriers
Vegetable butters are not carrier oils, but the beneficial properties of vegetable butters like Cocoa Butter and Shea Butter make them lipids that are suitable for use in aromatherapy. Vegetable butters are similar to vegetable oils but are solid at room temperature.