Talk about a time-traveling trend: Essential oils have shown up across cultures and continents from ancient Egypt to traditional Chinese medicine to today's drugstores.
"They have an important role in skin care — many are natural antiseptics and anti-inflammatories, and the scents are soothing," says Jennifer Linder, MD, an assistant clinical professor of dermatology at University of California, San Francisco.
Some claims about the benefits of essential oils are wild or confusing, though, so consider this your user's guide to the ones that work.
So what is an essential oil, anyway?
It's an intensely aromatic oil that's extracted from certain plants and flowers.
"If a plant is fragrant, it contains an essential oil," says Robert Tisserand, a California-based expert in aromatherapy and essential oils research, and coauthor of Essential Oil Safety. "It's what makes a rose smell like a rose, or a strawberry smell like a strawberry."
"As the steam hits a plant's petals or leaves, the tiny veins and glands that store the oil burst open and release it."
What you end up with is a concentrated essence that evaporates easily, allowing those teeny scented microparticles to float their way into your nose, your olfactory (or smell) receptors, your brain, and eventually your bloodstream and organs.
What should I do with them?
Two things: You can enjoy their delicious scents for the therapeutic benefits, or tap their skin benefits through oil-rich beauty products. Numerous small studies suggest that some oils, when inhaled, can lessen anxiety, help you fall asleep, reduce pain perception, or ease a stuffy nose.
"We use these herbal therapies all the time," says Jessica Hutchins, MD, an integrative medicine doctor at the Cleveland Clinic Wellness Institute. "They have tremendous healing properties and are exceptionally well tolerated."
Many essential oils have anti-inflammatory, antioxidant, antiseptic, or skin-repairing properties. (And sometimes they're added to beauty products for their dreamy fragrance alone — hey, we're not complaining.)
Do I put them right on my skin?
Nope — they need to be combined with other ingredients or diluted first.
"Your skin won't like pure essential oils," warns Patricia K. Farris, MD, an assistant clinical professor of dermatology at Tulane University Medical Center and past cochair of the American Academy of Dermatology's work group on complementary and alternative medicine. "Because essential oils are so concentrated, everything about them is intense — their scents, their beneficial active ingredients, and often their potential to irritate skin."
Even when mixed into products, if it's in high concentrations there's a chance they can make your skin angry. So always test a new cream or lotion first, says Farris.
"Put it on the skin behind your ear or on the underside of your arm for a few days. If you don't get a reaction, you're probably fine."
How can I tell if a product has essential oils?
You need to know what to look for on the ingredients list. To get the benefits of an essential oil, you want the plant-derived real deal, not a synthetic version made in a lab. Look for creams and lotions that list the plant's botanical name, says Tisserand. If it says "Lavandula angustifolia" in addition to "lavender," for example, it's likely to be the good stuff.
Should I sip essential oils?
Some companies make controversial health claims that drinking essential oils mixed into a glass of water can boost your immune system or cleanse your liver. There's some evidence that ingesting certain essential oils (in capsule form) may have therapeutic effects, but it could also cause harm. Bottom line: Skip it.
Why are some essential oils so expensive?
It takes a mega-amount of some plants to produce a small bottle's worth of the essential oil, so you may experience sticker shock when you shop. Rose oil is a good example: You're paying for the 1,000 pounds of rose petals that the farmer had to grow, harvest, and distill in order to get a scant 8 ounces of oil.