An Introduction to Carrier Oils in Aromatherapy

An Important Foundation for Aromatherapy Blending and Applications

Megan Tiehes, Certified Professional Aromatherapist

7/30/2026

A little introduction:

When learning about aromatherapy, there is an area that I find to be somewhat lacking; even within aromatherapy educational books and resources— that is carrier oils. Sure, you may see carriers listed in a recipe alongside a dilution rate, but does that make it the best carrier for everyone to use in their own unique situations? Not always. With no real explanation of why that particular carrier was chosen or what it is actually contributing to the blend, it can leave users unaware and often unwilling to alter from what they see on the page, even when it might be in their best interest to do so.

Carriers are more than just a way to quickly and easily “dilute” or “stretch” essential oils. Dilution is very important when it comes to safety in aromatherapy, but it is not the only purpose and consideration when it comes to carrier oils. Carrier oils also contribute to the performance, stability, and overall characteristics of a blend.

Understanding carrier oils in an important foundational aspect in aromatherapy because when choosing a carrier, we have to consider the purpose we are blending for, the area of application, any sensitives and preferences of the person we are blending for, the speed of absorption, the shelf life, and the personalized benefits of each carrier—allowing for better individualized and more effective blends. In other words, purposeful aromatherapy, is not only about selecting the right essential oil, selecting the right carrier is equally important.

What Is a Carrier Oil?

A carrier oil is a fixed oil—a non-volatile plant oil, meaning it does not evaporate at room temperature. Unlike essential oils, which readily evaporate into the air, fixed oils evaporate much more slowly. Their larger molecular structure makes them well suited as a base for topical aromatherapy applications. Fixed oils are drawn from the fatty portions of a plant— the seeds, nuts, or kernels.

From a chemistry stand point, most carrier oils are composed primarily of triglycerides—fatty acids bound to a glycerol backbone. They also naturally contain other beneficial plant constituents, including vitamins, phytosterols, and antioxidants. The types and amounts of these constituents vary from one carrier oil to another, giving each oil its own unique properties.

Liquid Oils vs. Solid Fats

Most carrier oils remain liquid at room temperature, making them easy to blend with essential oils. Others, are solid or semi-solid at room temperature and can also serve as a base in topical aromatherapy formulations.

Oils that are liquid at room temperature, such as olive oils, avocado oil, or hemp seed oil, tend to be higher in unsaturated fatty acids. The chemistry of the fatty acid chains prevents the molecules from packing tightly together, leaving the oil in a fluid state at room temperature.

Fats, or butters, that are solid or semi-solid at room temperature, like shea butter, coconut oil, or cocoa butter, are higher in saturated fatty acids. The molecular chains within these saturated fatty acids pack tightly together and hold a solid structure until warmed.

Neither category is superior to the other—they are simply suited to different roles in a formulation. For example, a liquid oil absorbs quickly and blends easily into a roller bottle, while a solid butter offers layer that can benefit slower absorption and offer benefit to the skin barrier.

Jojoba is an exception to the “fixed oil” definition when it comes to carrier oils. Though it behaves like an oil—liquid at room temperature, poured and blended the same way—jojoba is not a triglyceride at all. Chemically, it is a liquid wax ester and is structurally closer to the natural oils produced by human skin than to a true fixed oil. That wax ester structure helps jojoba resist oxidation far better than most true oils, giving it a notably longer shelf life and making it one of the most stable carriers used in aromatherapy.

Not All Carrier Oils Are the Same

One of the biggest misconceptions in aromatherapy is that any carrier oil will produce the same result.

Like essential oils, every carrier oil has its own unique chemical composition.

Some contain higher amounts of oleic acid, while others are richer in linoleic acid. Some absorb quickly, while others remain on the skin longer. Some are highly stable, while others oxidize more readily.

These differences influence everything from skin feel and absorption characteristics to shelf life and formulation choices.

Carrier Oils and Skin Support

The fatty acids and secondary constituents in a carrier oil help support the skin barrier and shape the overall feel of a topical blend. Because each carrier brings its own composition to the table, understanding these differences is what allows an aromatherapist to match a carrier to its intended use and overall goals and considerations for a blend, rather than reaching for whatever is on hand.

Essential oils are highly concentrated plant extracts. Applying them directly to the skin is not appropriate in most situations. Diluting essential oils in a carrier oil helps mitigate potential risks associated with topical use while allowing the essential oil to be distributed more evenly across the skin. Many oils have safety considerations that are mitigated with the use of carrier oils—potential irritation risk, sensitization, phytotoxicity, and so on.

Quality Matters

Carrier oils are natural plant products, and like any natural product, their quality shifts over time. Heat, light, oxygen, storage conditions, and an oil’s chemistry all influence how quickly a carrier oxidizes. As oxidation progresses, the aroma, texture, and color of a carrier change along with it. Proper storage—away from heat and light, in a well-sealed container—slows that process and protects both the quality and the usable shelf life of the carrier oil.

Processing Matters

Carrier oils can be processed in different ways, and the method used can influence the final characteristics of the oil.

Cold pressing uses mechanical pressure to extract oil without the use of chemical solvents. Because it involves less processing, cold-pressed oils often retain more of their naturally occurring constituents, including fatty acids, vitamins, and other plant compounds.

Unrefined oils generally undergo less processing and retain more of their natural aroma, color, and plant constituents compared with refined oils.

Refined oils may have a lighter aroma, more consistent appearance, and, in some cases, improved stability due to the removal of certain components.

Many aromatherapist's and aromatherapy educators suggest only using cold-pressed, unrefined carrier oils— seeing the naturally occurring constituents of the carrier oil as part of the desired benefits and formulation goals. These are what i tend to personally use and recommend. However, the best choice depends on the intended application, desired characteristics, and the needs of the individual blend— refined oils can be best for formulations that will be sold online or in stores, such as an aromatherapy shampoo bar, where consistency is needed and the scent and shelf-life have added importance.

Key take aways:

Carrier oils are an essential part of topical aromatherapy, contributing both to the safety of the blend and to its overall characteristics. The more we understand them, the more intentional we can become in selecting them.

From a professional aromatherapy standpoint, creating a topical blend is not just about choosing the right essential oil; it is equally about choosing the right carrier oil— that supports the purpose of the formulation, the intended application, and the individual needs of the person using it.

For the home essential oil user, understanding the carrier oils can still be greatly beneficial. However, I also recognize, that for many, it is NOT practical or financially feasible to have a wide variety of carrier oils taking up funds and space on the shelf. When it comes to pondering the paths of our feet, we must consider both the blessings and limitations of our current circumstances and make decisions based on what we have available.

Carrier oils matter.

  • Understanding them allows for more intentional choices.

  • Different carriers have different characteristics.

  • But using a readily available, appropriate carrier oil is still better than avoiding safe dilution because you don't have the "ideal" one.

Some of my favorite Carrier oils:

Avocado Oil: Shelf life: up to 3 years

Pure, unrefined avocado oil will be a dark green color, while the refined oil is more of a soft yellowish color. As it ages, the color tends to turn to a more brownish hue.

This is made from the flesh of the fruit. Any oil made from the seed is rare and toxic.

The constituents in this oil offer some of the following beneficial properties to this carrier:

· Anti-aging

· Moisturizing

· Soothing to irritated or sunburnt skin

· Can be used as a cleanser instead of soap

· Contains (unrefined):

o Vitamin E, with lower levels of vitamins A, D, and K.

o A high % of Oleic Acid. o Lower amounts of Linoleic acid and Palmitic Acid, with a few others at much lower concentrations.

Cocoa Butter:

Shelf life: 3-4 years (if stored cold)

This is a butter that is solid at room temperature but will soften when topically applied, due to the body’s heat.

I personally avoid purchasing both refined and solvent extracted forms. I choose to purchase extra virgin, unrefined, and organic coca butter.

The constituents in this oil offer some of the following beneficial properties to this carrier:

· Benefits for chronic skin issues

· Antioxidant

· Anti-aging

· Protects skin moisture barrier

· Contains (unrefined, cold- pressed):

o Vitamin E

o Stearic Acid

o Oleic Acid

o Palmitic Acid

Coconut Oil : Shelf life: ~2 years

Coconut oils is a solid at temperatures below 76 degrees F and a liquid when temperatures rise above this level.

I personally look for organic, unrefined, cold-pressed. I avoid completely avoid solvent extracted forms due to concerns with residual chemical contents and possible irritation. For making a commercially sold product that is not focused on the added beneficial ingredients of the carrier, but on the dilution, texture, and scent of the product, using a fractionated coconut oil can assist with consistency and shelf life.

The constituents in this oil offer some of the following beneficial properties to this carrier:

· Antibacterial

· Anti-fungal

· Anti-inflammatory

· Antioxidant

· Generally beneficial for wellness support with issues relating to irritated skin.

· Contains:

o Vitamin E

o Higher % of Lauric Acid

Jojoba Wax/ Jojoba Oil: Shelf life: Not Likely to go rancid

This oil is one of my favorite carrier oils. The long shelf life allows for longer storage of bother the blend and the carrier without the carrier adding to oxidation concerns.

This oil is well known to be very moisturizing to the skin. Its molecular structure resembles that of our natural skin sebum, and therefor working well with the skin. As we age, our natural sebum levels can decrease and use of jojoba may help replenish it.

The constituents in this oil offer some of the following beneficial properties to this carrier:

· Anti-inflammatory

· Antibacterial

· Known to be moisturizing without clogging pores.

· Skin barrio protectant

· Having benefits when used to support wellness in regards to irritated skin

· Contains (unrefined):

o High levels of Vitamin E

o High overall % of Eicosenic Acid

Shea Butter

Shelf Life: ~1 year

I focus on purchasing raw, organic, and unrefined for this carrier—the refining process involves a solvent (hexane) and effects the beneficial properties of the butter. When melting ingredients for a product, remember that this butter is sensitive to heat and should be added last.

The constituents in this oil offer some of the following beneficial properties to this carrier:

· Anti-aging

· Anti-inflammatory

· Moisturizing

· Skin protectant and supportive

· Contains (when unrefined):

o Surfactants and is often used in soap making

o High % of oleic acid and stearic acid

o Palmitic and Linoleic acids are at much lower %

Sources and farther reading:

Aroma Web has an entire list of Carrier Oil Profiles and some related articles. Check them out here: https://www.aromaweb.com/vegetableoils/index.php

Price, S., & Price, L. (2012). Aromatherapy for health professionals (4th ed.). Elsevier Churchill Livingstone.

Rhind, J. P. (2019). Essential oils: A comprehensive handbook for aromatic therapy (3rd ed.). Singing Dragon.

Tisserand, R., & Young, R. (2014). Essential oil safety (2nd ed.). Churchill Livingstone Elsevier.

National Association for Holistic Aromatherapy. (n.d.). What are carrier oils? NAHA. https://naha.org/explore-aromatherapy/about-aromatherapy/what-are-carrier-oils/