Essential oils have arguably become a core component of any self-care routine. Besides soaking up the fragrance from a diffuser, many are also now also adding them to baths and massages to take full advantage of their relaxing aroma. And many beauty products online boast having essential oils as one of their ingredients.
ICYMI, essential oils are plant extracts made by steaming or pressing various parts of a plant, such as flowers, barks, and leaves. The hype around them is backed up by preliminary research that shows essential oils can also be good medicine, according to Brent Bauer, MD, the director of the Complementary and Integrative Medicine program at the Mayo Clinic.
Essential oils offer many benefits—they possess antimicrobial and antibiotic properties, and they can help bust stress and even treat depression, to name a few, per a 2020 review in the Yale Journal of Biology and Medicine. That said, more studies in humans are needed.
They are also not regulated, so there's no way of knowing whether what you buy contains exactly what it claims. That doesn't mean you can't enjoy the calming effects of these oils—it just means you have to choose wisely and use them carefully. Your complete guide, ahead.
Essential oils carry the “essence” of the plant, explains Elizabeth Ko, MD, the medical director of the UCLA Health Integrative Medicine Collaborative and assistant clinical professor of medicine of the David Geffen School of Medicine at UCLA.
“Essential oils are quickly absorbed by smell receptors that are linked to the limbic system, which controls heart rate, blood pressure, breathing, and stress,” Dr. Ko says. “Each plant’s essence has a different chemical makeup that affects its smell, absorption, and effect.” There’s a lot to unpack with essential oils, though, and no two oils are exactly alike.
The findings are promising (imagine swapping pills for scents!), but they come with a few caveats: First, they're widely untested (read: there's not a whole lot of research out there). Also, you should use them judiciously. "Whatever is powerful enough to exert a beneficial effect in the body is powerful enough to exert a negative effect," says Dr. Bauer.
Essential oils release volatile organic compounds (VOCs), off-gases often linked to paints and pesticides. (Some VOCs are more hazardous than others, and "volatile" just means a substance can evaporate.) So while, for instance, moderate exposure to the best essential oils can be heart-healthy, prolonged exposure can pose cardiac risks.
Every essential oil has its own thing going on, and the perks you can get depend on the oil you use, says Yufang Lin, MD, an integrative medicine specialist at the Cleveland Clinic’s Center for Integrative Medicine.
The side effects depend on what oil you’re using and how you’re using it, Dr. Lin says. “Citrus-based essential oils, such as orange, lemon, and bergamot, are photo-sensitizers and can predispose someone to get a sunburn,” she says, if you put it directly on your skin, especially undiluted.
What's more: “Some essential oils are toxic to the nervous system and liver, such as tea tree and eucalyptus, and need to be used with caution around small animals and infants, the elderly, and pregnant women,” she adds. And some essential oils, like mugwort, pennyroyal, and wormwood, can cause your uterus to contract, so you don’t want to use them during pregnancy, she says.
People who tend to have strong reactions or allergies to fragrances or who have respiratory conditions should also be cautious when using essential oils, Dr. Ko says. But, overall, “safety testing shows very few risks when oils are used as directed,” she notes.
For the most part, there’s really no harm, no foul with trying essential oils, especially when it comes to aromatherapy. “As a therapy, essential oils are a low-risk, low-cost, effective intervention for symptom control,” says Dr. Ko.
The key is staying within a 15- to 60-minute sweet spot—never breathe in essential oils for more than one hour at a time. Always follow the instructions on the bottle, and if you are taking any medications or have a chronic health condition, ask your doctor before you start practicing aromatherapy. As with any other medicine, essential oils must be used correctly to yield health rewards.
A diffuser is the most effective way to unleash the best essential oils into the air, but if you don't have one (they run anywhere from $25 to $200), you can drip oil into a bowl of steaming hot water. In either case, use one or two drops of one oil at a time. Stand a few feet away and take 10 deep breaths, then breathe normally. If you stick within the safe time limit and open a window when you're done, you can practice aromatherapy every day.
At work or, say, in your car? Place one drop of one oil on a cotton ball, put it under your nose, and inhale normally for one to two minutes.
One thing to keep in mind: Since they're not yet FDA-regulated, the essential oils on store shelves may not be the real thing, says essential oil expert Megan Schwarz, the creator of the blog Seed to Serum. Follow these tips (recommended by Schwarz, Dr. Ko, and Dr. Lin) to make sure you purchase genuine products, then start shopping with our picks below.