Essential oils are often used in aromatherapy, a form of alternative medicine that employs plant extracts to support health and well-being. However, some of the health claims associated with these oils are controversial. This article explains all you need to know about essential oils and their health effects.

What are essential oils?
Essential oils are compounds extracted from plants. The oils capture the plant’s scent and flavor, or “essence.” Unique aromatic compounds give each essential oil its characteristic essence. Essential oils are obtained through distillation (via steam and/or water) or mechanical methods, such as cold pressing. Once the aromatic chemicals have been extracted, they are combined with a carrier oil to create a product that’s ready for use. The way the oils are made is important, as essential oils obtained through chemical processes are not considered true essential oils.
How do essential oils work?
Essential oils are most commonly used in the practice of aromatherapy, in which they are inhaled through various methods.
Essential oils are not meant to be swallowed.
The chemicals in essential oils can interact with your body in several ways.
When applied to your skin, some plant chemicals are absorbed (1Trusted Source, 2Trusted Source).
It’s thought that certain application methods can improve absorption, such as applying with heat or to different areas of the body. However, research in this area is lacking (3Trusted Source, 4Trusted Source).
Inhaling the aromas from essential oils can stimulate areas of your limbic system, which is a part of your brain that plays a role in emotions, behaviors, sense of smell, and long-term memory (5Trusted Source).
Interestingly, the limbic system is heavily involved in forming memories. This can partly explain why familiar smells can trigger memories or emotions (6Trusted Source, 7Trusted Source).
The limbic system also plays a role in controlling several unconscious physiological functions, such as breathing, heart rate, and blood pressure. As such, some people claim that essential oils can exert a physical effect on your body. However, this has yet to be confirmed in studies.
Essential oils can be inhaled or diluted and applied to the skin. They may stimulate your sense of smell or have medicinal effects when absorbed.

Popular types
There are more than 90 types of essential oils, each with its own unique smell and potential health benefits.
Here’s a list of 10 popular essential oils and the health claims associated with them:
- Peppermint: used to boost energy and aid digestion
- Lavender: used to relieve stress
- Sandalwood: used to calm nerves and help with focus
- Bergamot: used to reduce stress and improve skin conditions like eczema
- Rose: used to improve mood and reduce anxiety
- Chamomile: used to improve mood and relaxation
- Ylang-Ylang: used to treat headaches, nausea, and skin conditions
- Tea Tree: used to fight infections and boost immunity
- Jasmine: used to help with depression, childbirth, and libido
- Lemon: used to aid digestion, mood, headaches, and more
Health benefits of essential oils
Despite their widespread use, little is known about the ability of essential oils to treat certain health conditions.
Here’s a look at the evidence regarding some of the common health problems that essential oils and aromatherapy have been used to treat.
Stress and anxiety
It has been estimated that 43% of people who have stress and anxiety use some form of alternative therapy to help relieve their symptoms (8Trusted Source).
Regarding aromatherapy, initial studies have been quite positive. Many have shown that the smell of some essential oils can work alongside traditional therapy to treat anxiety and stress (9Trusted Source, 10Trusted Source, 11Trusted Source).
However, due to the scents of the compounds, it’s hard to conduct blinded studies and rule out biases. Thus, many reviews on the stress- and anxiety-relieving effects of essential oils have been inconclusive (12Trusted Source, 13Trusted Source).
Interestingly, using essential oils during a massage may help relieve stress, although the effects may only last while the massage is taking place (14Trusted Source).
A recent review of over 201 studies found that only 10 were robust enough to analyze. It also concluded that aromatherapy was ineffective at treating anxiety (15Trusted Source).
Headaches and migraines
In the ’90s, two small studies found that dabbing a peppermint oil and ethanol mixture on participants’ foreheads and temples relieved headache pain (16Trusted Source, 17Trusted Source).
Recent studies have also observed reduced headache pain after applying peppermint and lavender oil to the skin (18Trusted Source, 19Trusted Source).
What’s more, it has been suggested that applying a mixture of chamomile and sesame oil to the temples may treat headaches and migraines. This is a traditional Persian headache remedy (20Trusted Source).
However, more high-quality studies are needed.
Sleep and insomnia
Smelling lavender oil has been shown to improve the sleep quality of women after childbirth, as well as patients with heart disease (21Trusted Source, 22Trusted Source).
One review examined 15 studies on essential oils and sleep. The majority of studies showed that smelling the oils — mostly lavender oil — had positive effects on sleep habits (23Trusted Source).
Reducing inflammation
It has been suggested that essential oils may help fight inflammatory conditions. Some test-tube studies show that they have anti-inflammatory effects (24Trusted Source, 25Trusted Source).
One mouse study found that ingesting a combination of thyme and oregano essential oils helped induce the remission of colitis. Two rat studies on caraway and rosemary oils found similar results (26Trusted Source, 27Trusted Source, 28Trusted Source).
However, very few human studies have examined the effects of these oils on inflammatory diseases. Therefore, their effectiveness and safety are unknown (29Trusted Source, 30Trusted Source).
Antibiotic and antimicrobial
The rise of antibiotic-resistant bacteria has renewed interest in the search for other compounds that can fight bacterial infections.
Test-tube studies have investigated essential oils, such as peppermint and tea tree oil, extensively for their antimicrobial effects, observing some positive results (31Trusted Source, 32Trusted Source, 33Trusted Source, 34Trusted Source, 35Trusted Source, 36Trusted Source, 37Trusted Source, 38Trusted Source, 39Trusted Source).
