A peek into safe use of essential oils

Essential oils have soared in popularity. Here is a primer to help you guide your patients in their safe use.

The basics

Essential oils are highly concentrated aromatic oils of plant origin that are  by steam distillation, hydrodiffusion, or pressure. They get their fragrances and therapeutic characteristics from chemical components that include monoterpenes, esters, aldehydes, ketones, alcohols, phenols, and oxides. Plant species may have different chemovarieties that may different clinical effects. These variations of subspecies produce essential oils with different chemical compositions as a result of genetic variation and growth conditions.

It is important to use the Latin name of the parent plant when researching essential oils because multiple essential oils come from plants in the same genus. Different parts of the plant make different oils. For example, in Citrus aurantium, neroli is the flower, bitter orange is the fruit peel, and petitgrain is the leaf.

To determine the quality of an essential oil product, look on the label for the Latin name of the parent plant; the part of the plant from which the oil was derived; indication that the oil is for external use only; a warning against its use in undiluted form; a warning to keep the product away from eyes and mucous membranes; and an expiration date or date of manufacture. The presence of this information doesn’t guarantee a product is of good quality, but reputable manufacturers should include it.

To make further determinations about quality, it is useful to know the batch identifier, extraction process, and country of origin. Keep essential oils in the refrigerator to slow oxidization, which will affect its potency. Oxidized oils will have an altered smell, and viscosity may change as oils oxidize.

Use caution

Kelly Holland Azzaro, RA, CCAP, LMT, is an aromatherapist with nearly 3 decades of experience. Azzaro is also past president of the National Association for Holistic Aromatherapy (NAHA), which promotes academic standards in aromatherapy education and practice standards for the profession. According to Azzaro, aromatherapy—the practice of using essential oils for therapeutic purposes—in the United States consists mostly of inhaling and massaging essential oils into the skin, not ingesting the oils. Patients can avoid most of the safety risks associated with essential oils by using them externally only. Still, there are dangers.

“People unfortunately will put [a large amount of an essential oil] diffuser unit, which diffuses 500 to 1,500 square feet, in their bedroom, and that could be overpowering for their children or their pets,” Azzaro said. “Or they might only need it for an hour before bedtime versus letting the diffuser run all night long. That can cause an issue where they become desensitized over time because they’ve been using lavender every single night to help with sleep.”

Tisserand Institute, an organization that translates "new research and scientific findings into comprehensive educational material about the benefits of essential oils” and was founded by leading aromatherapy expert Robert Tisserand, recommends intermittent diffusion, alternating 30 to 60 minutes of diffusion with an equal amount of time of no diffusion.

For massage, “it’s important for pharmacists to know that essential oils applied topically need to be diluted in a carrier oil, not put right on the skin,” Azzaro said. Popular carrier oils include jojoba, coconut, olive, almond, avocado, flaxseed, and argan oils.

Proper dilution is key to safe topical use of essential oils. According to the Tisserand Institute, using an average dropper, 30 drops equals 1 mL. For 15 mL of base oil, create a 5% concentration with 22 drops of essential oil; 4% concentration with 18 drops of essential oil; 3% concentration with 13 drops of essential oil; 2% concentration with 9 drops of essential oil; 1% concentration with 4 drops of essential oil; and a 0.5% concentration with 2 drops. Concentrations above 2.5% should be used very carefully, preferably in consultation with a NAHA-approved aromatherapist.

Skin stuff

Some essential oils are known dermal irritants, with severity depending on concentration. According to NAHA, these should not be used on any inflammatory or allergic skin condition and should always be properly diluted in vegetable oil.

Dermal irritants include bay (Pimento racemosa), cinnamon bark or leaf (Cinnamomum zeylanicum), clove bud (Syzygium aromaticum), citronella (Cymbopogon nardus), cumin (Cuminum cyminum), lemongrass (Cymbopogon citratus), lemon verbena (Lippia citriodora), oregano (Origanum vulgare), tagetes (Tagetes minuta), and thyme chemotype thymol (Thymus vulgaris).

Patients should also be aware that some essential oils will make them more sensitive to the sun and ultraviolet rays like those encountered in a tanning bed. Anyone who has applied photosensitizing essential oils should avoid the sun or tanning salon for at least 24 hours. According to NAHA, photosensitizing oils include Angelica root (Angelica archangelica), bergamot (Citrus bergamia), cumin (Cuminum cyminum), expressed lemon (Citrus limon), expressed lime (Citrus medica), expressed bitter orange (Citrus aurantium), and rue (Ruta graveolens).

Consult the experts

Azzaro urges pharmacists to consult the resources on NAHA’s website, , and to direct patients to the site’s “Find an Aromatherapist” tool. “When it comes to specific health issues, it’s best that they work with somebody who's trained so they know if there are any problems. Something might be good for migraines, but it might not be good for a specific person,” she said. “With children it’s even more of an issue, although there are some essential oils that can be used with children, as well as hydrosols, which are much gentler than essential oils.” Azzaro also recommends hydrosols as a safer alternative to essential oils for older adults, pets, and those with complex health conditions.

The Tisserand Institute at is another good resource for both pharmacists and patients.

For the full article, please visit for the August 2019 issue of Pharmacy Today.