These essential oils have science-backed health benefits

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Q: I’ve heard essential oils can help treat stress, insomnia and other health conditions. Is that true? What does the research say?

A: From a purely medical perspective, it’s hard to say that many essential oils are doing anything profound. The health claims linked to most varieties, such as citronella, bergamot, rose and sandalwood, are lacking in convincing data from clinical studies.

But there is reasonable medical evidence for a few uses, including:

-Peppermint oil capsules for irritable bowel syndrome

-Lavender oil capsules or aromatherapy for sleep and anxiety

-Tea tree oil applied topically for acne

Essential oils are often extracted through distillation methods that use steam to extract the oils from plants. You should never ingest pure essential oils, such as those from the vial, as this may be toxic. Instead, look for products containing essential oils that are meant for ingestion, as is the case of IBgard, an over-the-counter peppermint-containing product for irritable bowel syndrome.

Likewise, avoid applying pure essential oils directly on the skin. Instead, dilute them to 1-5 percent concentration using your favorite lotion or another carrier oil, such as olive oil. This helps lower the risk of contact dermatitis.

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Peppermint oil

The active ingredient in peppermint is menthol, which relaxes the muscles of the human gastrointestinal tract. A 2022 meta-analysis of 10 randomized controlled trials looking at ingestion of peppermint oil in treating irritable bowel syndrome symptoms found it to be more effective than a placebo (many of the studies were industry-funded).

Peppermint may be especially helpful for abdominal pain, though as a caution, it can aggravate heartburn symptoms. Peppermint is recommended by the American College of Gastroenterology, and I find it reasonable to try for mild symptoms, though many patients with irritable bowel syndrome and similar disorders may ultimately benefit more from other therapies. I generally recommend trying one peppermint oil capsule three times a day.

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Lavender oil

Lavender is thought to exert its effects on sleep and anxiety in our central nervous system in a somewhat similar fashion to the medication pregabalin, an analgesic.

In Germany, a medication containing lavender oil, silexan, is approved for anxiety-related symptoms. Several randomized controlled trials have shown lavender capsules to improve anxiety symptoms both compared to a placebo and, in the case of high-dose silexan, compared to paroxetine, a medication commonly used to treat depression. These studies were predominantly done in women, and many were funded by the manufacturer.

A 2022 meta-analysis looking at essential oil aromatherapy on sleep quality among cancer patients found lavender oil was moderately effective and performed better than other essential oils, like chamomile or orange. In the studies analyzed, lavender oil in aromatherapy was done through massage or directly inhaled after dilution – for example, putting the oil on a cotton ball that was kept around the patient’s collar for 20 minutes.

It bears noting the studies tend to follow patients for only a few weeks at most so lavender oil is more likely to help as a short-term aid.

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Tea tree oil

With tea tree oil, which has some antimicrobial properties when applied to the skin, two trials are worth noting: One was a study of 5 percent tea tree oil from 1990 that found it equally effective as 5 percent benzoyl peroxide for treating acne, though the oil was slower to act. The second was a 2007 double-blind trial that found a 5 percent tea tree oil gel to be more effective than a placebo in reducing acne severity. For some, tea tree oil irritates the skin, but for others with acne who prefer a more natural option, the data are encouraging.

To try it for acne, apply a thin layer of 5 percent tea tree oil to the affected area twice daily and leave it on for 20 minutes. Afterward, wash the area thoroughly with water.

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Does it matter where you buy essential oils from?

Essential oils are generally not regulated as medications by the Food and Drug Administration in the United States, so it can be hard to know what exactly you’re getting when you buy these over-the-counter or online. Look for essential oils that come from a reputable company and have few, if any, additives that may irritate the skin.

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What are the risks of using essential oils?

In 2007, there was a small case series published in the New England Journal of Medicine linking gynecomastia – an enlargement of breast tissue – in young boys to exposure to tea tree and lavender essential oils. It got some buzz in the press at the time, but larger peer-reviewed studies since then have failed to show a connection.

There are a few caveats still worth noting: Many essential oils can make your skin more sensitive to sun damage, so I would not rub any in before heading outside. Several essential oils, including tea tree oil, are toxic to dogs and cats.

Avoid vaping essential oils and keep your exposure short: Limited human data suggests that inhaling essential oil vapors for longer than one hour can be harmful to cardiovascular health. Because of their possible irritating effects on the lungs, the American Lung Association does not recommend people with asthma or COPD use essential oils.

In general, it’s best to discuss with your health care provider before using essential oils, especially if you’re pregnant or have young children.

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What I want my patients to know

Essential oils have been used for millennia in healing and bathing rituals across many cultures. I have no problem with my patients incorporating the oils in a personal care routine if doing so makes them feel luxurious. But to me, the more important question if you suffer from poor sleep is not whether lavender essential oil will help your symptoms, but whether we can address the underlying issue causing it. Similarly, for anxiety, we still need to find a long-term solution.

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Trisha Pasricha is an instructor of medicine at Harvard Medical School.