Carrier Oils: Introduction
Carrier oils, also known as base oils or fixed oils, are used in many natural cosmetics, massage oils, and skin care products. Their job is to 'carry' other ingredients into the skin and to dilute essential oils and other absolutes. Applying undiluted essential oils and other concentrated ingredients directly on the skin can cause severe irritations or reactions in some people. Carrier oils are used to dilute these ingredients, and also to help them absorb deep into the skin where their nutritional benefits are more effective.
The carrier oils you use should be as close to natural and organic as possible. Cold-pressed oils are best. Other extraction methods (like heat or solvent extraction) destroy vital nutrients in the oils.
Essential oils (volatile oils) are different than carrier oils (fixed oils). Both can be obtained from the same plant, but are extracted differently, and have different properties. Carrier oils are pressed from the fatty portion of the plant such as the seeds, kernels, or nuts. Essential oils are distilled from various parts of the plant, such as the leaves, flowers, fruits, bark and seeds. They are considered 'essential' because they carry a distinctive scent, but don't necessarily have specific medicinal or chemical properties. Carrier oils do not have a very strong aroma. They usually smell faintly sweet or nutty, sometimes odorless. Neither do they evaporate like essential oils, which are more volatile, and have a more concentrated aroma. Carrier oils will go rancid over time, turning bitter and foul smelling. Rancidity happens quicker when exposed to heat, air, and light. Essential oils will oxidize over time, loosing their therapeutic benefits.
Carrier oils are not only for 'carrying' other ingredients. Since these oils often make up a bulk of the material used in massage and skin care products, their vitamin, mineral and fatty acid content play a major role in the nutritional and therapeutic benefits of the finished product. They also to help prevent skin dehydration, and act as lubricants to help with massage movements.
Some oils are high in vitamin E, a fat soluble antioxidant with powerful healing and protective properties. It can also help to prolong an oil's shelf-life. Others contain essential fatty acids, like alpha-linolenic acid (omega-3), and linoleic acid (omega-6). These fatty acids are essential for good health but are not created within the body and must be obtained form other sources. Generally, all carrier oils contain some combination of saturated, monounsaturated, and polyunsaturated fats. A fatty acid is considered saturated or unsaturated depending on whether their carbon atoms contain a single bond C-C between the atoms, or a double bond C=C. Compounds with single bonds are said to be saturated. Those with double bonds are unsaturated. Monounsaturated fats have a single double bond, whereas polyunsaturated fats have more than one double bond. Some common fatty acids include: oleic acid, linoleic acid, linolenic acid, palmitic acid, and stearic acid. The degree of saturation in a carrier oil will effect the oils' absorption, it's shelf-life, and whether it is drying, semi-drying, or non-drying to the skin. For more information on the different fatty acids, see section: Fatty Acids & Other Ingredients.
Generally, oils high in saturated fats (such as palmitic acid, stearic acid, lauric acid, etc.) have longer shelf-lives, and are non-drying. Oils high in monounsaturated fats (such as oleic acid, palmitoleic acid, gadoleic acid, etc.) can be non-drying to semi-drying. Oils high in polyunsaturated fats (such as linoleic acid, alpha-linolenic acid, gamma-linolenic acid, etc.) tend to have relatively low shelf-lives, good absorption qualities, and are drying.
Non-drying oils (almond, castor, olive, peanut, coconut, etc.) are useful for dry skin that needs moisture. They do not harden when exposed to air, and remain in a liquid state for quite some time. Semi-drying oils (sesame, sunflower, etc.) are suitable for normal to oily skin, and will partially harden when exposed to air. Drying oils (hemp seed, etc.) are more suitable for oily skin, but are better mixed with other oils in a blend. Drying oils will harden completely, forming a solid film when exposed to air.
Oils also vary in their viscosity, or thickness. Fine, light, less viscous oils will be absorbed quickly without leaving a greasy feel on the skin. These oils are preferable for use on the face, and may help to balance oiliness. Heavier, more viscous oils are suitable for dry skin, and as body, bath and massage oils. Heavier oils may sit on the surface of the skin longer before they are absorbed, and are not recommended for already oily skin. However, heavy oils will not make skin oiliness worse.
Choosing which carrier oils to use depends on the therapeutic benefits being sought, your (or your client's) needs and sensitivities, the area being treated, and the desired color, aroma and shelf-life of your final product. When purchasing oils, look for those that are cold-pressed, organic, and in the case of olive oil, 'extra-virgin'. Look for oils that are in dark-colored glass bottles or (non-aluminum) metal containers. These containers protect the oil from rancidity caused by exposure to light. Also, try to buy oils in relatively small quantities. The more oxygen the oils are exposed to (by constantly opening and closing the bottles), the quicker they will go rancid. It is best to replace oils with fresh ones rather than using the same oil from a large container for a long period of time. Oils from the grocery store are often heated and are not suitable for use on the skin (and are not too great for eating either). Generally, the less processing an oil goes through, the better and more nutritious the oil will be. See the above table on extraction methods for more information.
All carrier oils should be kept in a cool, dry place away from strong light to slow rancidification. Refrigerating oils may help preserve their freshness, but keep in mind that some oils are too sensitive and could be damaged by the cold, such as avocado oil. If using carrier oils in a massage blend, it is best to prepare it fresh at the time of treatment. This is because some oils have a short shelf-life, and because the client's needs may be different from day to day.
NOTE: Do not use mineral oil. It is derived from petroleum and is not absorbed through the skin.
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References: View works cited for "Carrier Oils".
