Our cognitive ability determines how well we perform at work, our ability to succeed, how good we feel, and our overall state of mental well-being. The term cognition encompasses many elements, including learning, memory, language, and focus.
A hectic lifestyle and greater demands expected from Americans in today’s society have strongly impacted our cognition. In fact, a report from the CDC shows that 1 in 9 adults in the United States are dealing with cognitive decline. 
This staggering number demonstrates the importance of maintaining brain health. Essential oils have been used medicinally for thousands of years. However, it wasn’t until more recently that essential oils have been found to improve mental health. Continue reading to learn how essential oils can enhance brain function.
What are Essential Oils?
Essential oils are concentrated substances extracted from plants that have potential health benefits. These oils contain a large dose of the active ingredient and have a more powerful scent than the plants they are obtained from.
Although they are used in a variety of products, essential oils are more commonly utilized in aromatherapy, which is a type of complementary medicine that uses your sense of smell to boost general health. Upon inhalation, the molecules from the oil go directly to the brain. In terms of brain health, essential oils can help to:
- Enhance mood
- Improve sleep
- Reduce symptoms of anxiety
- Improve cognitive performance
Are the Benefits for Brain Health Supported by Research?
One 2017 study compiled detailed research from various peer-reviewed journals demonstrating that essential oils work in different ways to achieve improved cognition, mood, sleep, and anxiety. 
For instance, these oils are effective at reducing oxidative stress.  The brain is the organ most commonly affected by this. Oxidative stress is when there is an excess of harmful substances called free radicals that lead to brain cell death. By reducing oxidative stress and acting as antioxidants, essential oils are considered neuroprotective because they protect nerve cells found in the brain from damage or death.
There are also many other studies available that focus on the brain health benefits of individual essential oils, some of which will be referenced in this review.
Best Essential Oils for Brain Health
Rosemary Essential Oil
The essential oil extracted from rosemary is a strong antioxidant that also has antibacterial and antifungal properties. As an antioxidant, it can help prevent brain cell death and damage. Rosemary has also been studied in the treatment of dementia and Alzheimer’s disease, which are disorders characterized by cognitive decline.
One of rosemary’s components, 1,8-cineole is well known to enhance overall cognition,  and the extract of rosemary has been shown to improve memory impairment in dementia models. 
One study gave participants various tasks representing different aspects of cognitive function. Individuals that inhaled rosemary essential oil resulted in significantly improved performance of memory and heightened alertness. 
Lavender Essential Oil
Lavender is known for its calming and pleasant fragrance, but it is also involved in a number of cognitive benefits. Inhaling lavender has been shown to increase the number of antioxidant enzymes that work to combat free radicals, thereby protecting brain cells. 
Lavender may also reduce symptoms associated with general anxiety disorder. An article published in the National Library of Medicine looked at available research regarding this and concluded that lavender does, indeed, produce a calming effect as an aromatherapy treatment. 
Lemon Essential Oil
This essential oil significantly increases memory and recall ability.  Among being used to help treat other diseases, such as diabetes, cardiovascular disease, and depression, lemon essential oil also improves cognitive function in patients with Alzheimer’s disease.
One study that examined the effects of lemon essential oil in mice demonstrated that it improved learning ability and memory.  It achieved this by inhibiting a substance called acetylcholinesterase, which is responsible for breaking down acetylcholine.  When acetylcholine is broken down, memory and concentration become poorer.
Peppermint Essential Oil
From improving symptoms associated with irritable bowel syndrome and easing indigestion to treating nausea and reducing pain, the health benefits of peppermint essential oil seem endless. Aromatherapy with peppermint oil can help with symptoms of cough and colds, improve cognitive function and invigorate the body to increase alertness and improve exercise performance.
One recent study that examined anxiety, stress, memory, and sleep in college students concluded that peppermint appears to have reduced anxiety and stress, boost memory, and improve sleep quality in those students. 
Frankincense Essential Oil
An underestimated essential oil, frankincense has a variety of mental health benefits, such as improving memory retention, increasing productivity, and stimulating better concentration.
A small recent study was performed on older men who were given various mental tasks and completed questionnaires to account for memory. The study concluded that those taking frankincense had better retention of motor memory compared to those who didn’t take frankincense. 
Although more studies are needed on human subjects, there is a vast amount of research confirming that essential oils, particularly the ones mentioned in this article, are excellent therapeutic options for those of us experiencing mental decline for whatever reason. They are also helpful in promoting an elevated mood and general mental wellness.
Inhaling essential oils is the safest way to consume them. They may also be rubbed on the skin or consumed orally. The high concentration of essential oils may irritate the skin and could cause a potential allergic reaction. Ingesting them orally introduces a different set of side effects. In either case, you should speak with your doctor before using any essential oils in this manner.
If you have any respiratory disorders, you should speak with your doctor before using essential oils as aromatherapy. However, if you are generally healthy and you diffuse essential oils in a well-ventilated area for short periods of time, using them as aromatherapy is generally considered safe.