Center for Research on Ingredient Safety

Updated: May 13, 2024

What are essential oils?

Essential oils are compounds extracted from various plant parts, including flowers, leaves, bark, seeds, roots, and more.

Manufacturers typically use essential oils as flavor or aroma enhancers in cosmetics, food additives, soaps, plastic resins, perfumes, and more.

Note that there is a difference between essential oils and crude plant extracts in terms of purity, composition, and the acquisition process. Oils produced by adding chemical solvents to the plant parts are not typically considered essential oils.

How are essential oils created?

Creating essential oils requires manufacturers to extract the oils from the plant. There are three primary methods used to extract essential oils from plants: steam distillation, cold pressing, and solvent extraction (1,2). 

• Steam Distillation: Plant materials are placed in a distillation apparatus over water. Steam passes through the plant material as the water is heated, vaporizing the volatile compounds. The steam and the plant oils then pass through a cooling system to condense the steam back into water. The essential oil separates from the water and is collected. This method is favored for its efficiency and the high purity of oil it produces.
   
• Cold Pressing: Also known as an expression or mechanical pressing, this method is frequently used for citrus essential oils. The outer rind of the fruit is mechanically pressed to extract the essential oil. No heat is involved, which helps maintain the oil's natural integrity and flavor.
   
• Solvent Extraction: This method involves using solvents like hexane, ethanol, or methanol to extract the essential oils. It is typically used when the aromatic compounds are too delicate or tightly bound in the plant to be efficiently released by steam distillation. The plant material is treated with a solvent that dissolves the desired aromatic compounds. The solution is then filtered and concentrated by distillation to remove the solvent, leaving behind the essential oil. 

Each method has advantages and specific applications, and it is chosen based on the type of botanical material and the properties of the oil needed.

What are essential oils used for?

When looking at products, manufacturers use essential oils to enhance the flavor or aroma of many cosmetics, food additives, soaps, plastic resins, perfumes, and more.

Researchers are actively exploring innovative applications of essential oils, including their use in food preservation and packaging, as well as potential therapeutic roles in treating specific mental and physical health conditions (1,2,3,4,5,6,7,8).

Many people use essential oils in aromatherapy. Aromatherapy is a non-regulated healthcare practice, often referred to as holistic medicine, that incorporates essential oils into a variety of activities such as massage, baths, meditation, and more to promote and improve human health.

An aromatherapist may recommend a specific essential oil and activity to help a person with a particular physical symptom they may be experiencing. For example, an aromatherapist may recommend that someone suffering from poor sleep quality incorporate lavender oil into a nightly bath to help ease tension and improve sleep quality.

Do essential oils cure or prevent diseases, are they medications?

Commercially available essential oils are not pharmaceuticals that fall under the purview of the U.S. Food and Drug Administration (FDA). This means commercially available essential oils are not known to treat, cure, or prevent diseases. However, the FDA and the Federal Trade Commission (FTC) can and will enforce laws that prohibit companies from selling products containing essential oils as medications with curative properties.  

While essential oils are not pharmaceutical drugs, there is ongoing, preliminary research investigating the potential therapeutic effects of specific essential oils (1,2,3,4,5,6). 

It's important to remember that the essential oils used for research can vary dramatically in purity, potency, dosage, and more compared to commercially available oils.

You should not use essential oils instead of visiting a state-licensed, credentialed medical doctor to treat ailments.

What do I need to know about essential oil use?

It's important to pay attention to the instructions that come with essential oils. Often, users need to add essential oils to a carrier medium, such as coconut or jojoba oil, before applying them to their skin. The carrier medium dilutes the essential oil, which helps prevent the concentrated essential oil from harming the skin.

People often put essential oils into a diffuser that emits a scented mist into the air, or they add a few drops of essential oils to bath water or laundry to enhance the smell. Some people believe the scent can help alleviate physical symptoms of specific conditions like sleeplessness due to anxiety. Although some studies support this idea, research in the field is still at an early stage and requires more extensive, large-scale studies (1,2,3,4).

How do I find quality essential oils?

Currently, no U.S. regulatory agency certifies or approves essential oils for their quality and purity.

Manufacturers use many marketing terms, such as "therapeutic grade" or "pure" to sell products. However, those terms do not reflect the product's quality.

It's important to look at the manufacturer and read the ingredient labels before purchasing an essential oil to understand what the product contains. While there is no certificate for essential oils, reputable companies will identify the plant ingredient, typically by the formal Latin name, as well as the extraction process used to produce the essential oil.

A word of caution.

Aromatherapists and many holistic medical practitioners are not credentialed medical doctors and are unable to provide the same level of care as a state-licensed and credentialed medical doctor.

Essential oils are not regulated pharmaceuticals like prescription drugs, which means they haven't undergone the intensive research required to demonstrate both safety and efficacy, which is required for FDA-regulated medications.

While essential oils are not regulated drugs, they are not harmless. If misused, they can cause harm and should only be used as intended and kept out of the reach of children.

Additionally, using essential oils, especially ingesting oils, to treat medical conditions can cause serious bodily harm. It's important to talk with a medical expert before beginning treatment, holistic or otherwise, for any medical ailment.

The good news.

Our understanding of essential oils and their potential applications continues to evolve as we explore innovative uses for these botanical-based compounds. Although we don't have all the answers, continued research will help us understand these ingredients' safety and how we can better use the essential oils.

If you have any questions about foods and ingredients, please reach out to us on Twitter, send us an email, or submit your idea to us at go.msu.edu/cris-idea.