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.

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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.

Meet the experts: Elizabeth Ko, MD, is board-certified in internal medicine and integrative medicine and is a fellow of the American College of Physicians. She writes the national syndicated column, "Ask The Doctors."

Brent Bauer, MD, oversees the Mayo Clinic Complementary and Integrative Medicine and is actively involved in the research conducted there. His main research interests include massage therapy, acupuncture, herbal and dietary supplements, and mind-body applications.

How does aromatherapy work?

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.

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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.

What are the health benefits of essential oils?

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.

  • They might help reduce anxiety. Several essential oils like orange and lavender have been shown to help people be a little less anxious. Worth noting: Some research has found that the perks only happen in the moment, like when you’re getting a massage.
  • They may ease headaches. Some smaller studies have found that people reported less headache pain after they applied peppermint and lavender essential oil to their skin. One study even found that there wasn’t a significant difference between using peppermint oil for reducing pain and taking acetaminophen (aka Tylenol).
  • They can make your sleep better. Lavender, in particular, has been shown to boost the ability to get to sleep and wake up feeling awesome.
  • They may reduce inflammation. Some essential oils might help ward off inflammation, says Dr. Lin. Research on mice and in petri dishes has found oils like lavender, thyme, and oregano may be good for this, but there still needs to be more studies done on humans.
  • They can give you an energy boost. Coffee is great and all, but a little peppermint can also help stimulate you, says Dr. Ko. One small study found that men who used peppermint oil were able to perform better at the gym than those who didn’t. (More research is needed in women, though.)
  • They might help your stomach issues. Lemon in particular is good for combating things like nausea and vomiting, Dr. Ko says. One study on pregnant women found that those who smelled lemon oil when they felt ill had significantly less nausea and vomiting in the days afterward than women who didn’t.

What are the potential side effects of essential oils?

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.

What's the best way to use essential oils?

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.

  • Beware the blanket aromatherapy label, often slapped on diluted oils laced with synthetic fragrances.
  • Look for 100 percent pure and organic oils free of fillers, pesticides, and synthetic chemicals.
  • If a label says therapeutic grade or steam distilled, even better.
  • Most essential oils have long shelf lives—more than a year if stored in a cool, dry place. If the shop you're in is hot or humid, buy elsewhere.

1. Lavender

doTERRA Lavender Essential Oil
doTERRA Lavender Essential Oil
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$29 at Amazon

Use it: For better sleep
The OG best essential oil for relaxation, lavender can help people sleep better and wake up more refreshed, research shows. And lavender has been shown to reduce anxiety, according to the National Sleep Foundation, making it clutch for nights when racing thoughts are keeping you awake.

Bonus perks: Lavender is associated with lower blood pressure, heart rate, and skin temperature.

2. Clary Sage

Plant Therapy Clary Sage Essential Oil
Plant Therapy Clary Sage Essential Oil

Use it: To reduce blood pressure
Women who smelled clary sage experienced reduced blood pressure and breathing rates in a 2013 study; they were also able to relax during a stressful medical exam.

Bonus perks: It may help with memory and attention.

3. Peppermint

Plant Therapy Peppermint Essential Oil
Plant Therapy Peppermint Essential Oil

Use it: To wake up
Research shows that breathing in peppermint can make people feel more alert and can boost their memory.

Bonus perks: It may reduce both fatigue and chocolate cravings.

4. Orange

Pure Certified Organic Essential Oil
Nature's Oil Pure Certified Organic Essential Oil

Use it: To decrease anxiety
A study found that women who sniffed it during labor (a.k.a. arguably the most nail-biting experience of a woman's life!) felt less anxious.

Bonus perk: It may help with PTSD, according to one study.

5. Rosemary

Rosemary Essential Oil
Healing Solutions Rosemary Essential Oil
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Use it: To enhance brainpower
Breathing in rosemary can improve speed and accuracy during demanding mental tasks, per a 2012 study. Other research found its scent left people feeling refreshed and mentally stimulated.

Bonus perks: It may help boost energy and reduce fatigue.

6. Cinnamon

Majestic Pure Cinnamon Essential Oil
MAJESTIC PURE Majestic Pure Cinnamon Essential Oil
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Use it: To boost focus
It may stoke the area of the brain that governs alertness. For example, research found that drivers were more focused and less flustered after breathing in cinnamon-oil scents.

Bonus perks: It increases concentration and reduces frustration.

7. Lemon

Plant Therapy Lemon Organic Essential Oil
Plant Therapy Lemon Organic Essential Oil

Use it: To improve mood
When life give you lemons, sniff! Research shows oil from the fruit's peel may enhance mood. Researchers found that inhaling the aroma of lemon essential oil was more effective in improving mood than aromatherapy involving the use of lavender essential oil in a study published in Psychoneuroendocrinology.

Bonus perks: It may ease anxiety and stress.

8. Eucalyptus

Majestic Pure Eucalyptus Essential Oil
MAJESTIC PURE Majestic Pure Eucalyptus Essential Oil

Use it: To stop sniffling
Combat congestion with eucalyptus oil; it reacts with mucous membranes, reducing mucus. But eucalyptus oil is strong, so you only need one or two drops.

Bonus perks: It promotes mental clarity and soothes headaches for some people.

9. Bergamot

doTERRA Bergamot Essential Oil
doTERRA Bergamot Essential Oil

Use it: To achieve maximum chill
Women who inhaled bergamot had lower levels of saliva cortisol (the stress hormone) in one small study. The scent also helped patients in a mental health treatment center feel most positive, according to a 2017 study.

Bonus perks: It may boost your mood.

10. Lemongrass

Rocky Mountain Oils - Lemongrass
Rocky Mountain Oils - Lemongrass

Use it: To curb worry
People in one study who were exposed to lemongrass essential oil immediately saw anxiety and tension level slashed, and they recovered more quickly from a stress-inducing situation compared to those who didn't inhale the scent.

Bonus perks: It helps keeps insects away.

11. Ylang Ylang

Organic Ylang Ylang Essential Oil
Healing Solutions Organic Ylang Ylang Essential Oil

Use it: For relaxation
One study found that people had a lower heart rate and blood pressure after sniffing ylang ylang.

Bonus perks: It can soothe inflammation.

12. Sandelwood

Sandalwood Essential Oil
Gya Labs Sandalwood Essential Oil
Credit: Courtesy

Use it: For a mood boost
Research has found that sandalwood can help improve depressive symptoms in people during a massage.
Bonus perks:
It can help sharpen your focus too.

13. Chamomile

Roman Chamomile Essential Oil
Healing Solutions Roman Chamomile Essential Oil
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Use it: For deep shut-eye
Roman chamomile has been found to help people sleep better when it’s applied during a massage.

Bonus perks: It calms nerves.

14. Jasmine

Woolzies 100% Pure Jasmine Essential Oil Blend
Woolzies 100% Pure Jasmine Essential Oil Blend
Credit: Courtesy

Use it: To lift your mood
People who were exposed to jasmine in one study reported feeling more positive and upbeat afterward.

Bonus perks: It may have an aphrodisiac effect.

15. Grapefruit

Grapefruit Essential Oil
Gya Labs Grapefruit Essential Oil

Use it: To calm down
One rat study found that grapefruit essential oil helped lower blood pressure in rats. The theory is that limonene, the active ingredient in grapefruit oil, did the trick.

Bonus perks: It can help balance your mood.