The Full Guide to Essential Oils: Literally Everything You Need to Know


What’s your favorite floral scent? Roses? Jasmine? Or maybe you have a favorite herb like rosemary or oregano that evokes wonderful cooking aromas? The luscious scents wafting into your nose originate from the plant’s essential oils.

Plant leaves and other parts are crushed or distilled, and in the process, release of the essential oils occurs. The product is then bottled in a pure, highly concentrated form. Essential oil uses range from aromatherapy and personal beauty care to household cleaning products and even natural medicine treatments.

If you’re intrigued by essential oils, but totally overwhelmed, this comprehensive guide covers all the basics. Let’s dive right in!

How to choose essential oils

There are many different types of essential oils. Some come from fruits like oranges or lemons, while others come from herbs like basil or peppermint. Still others come from flowers like geraniums or roses. Every part of the plant—flowers, stems, seeds, roots and bark—has essential oils, each with a different chemical composition.

The essential oil that you choose to use depends on your purpose. What is it that you want to do? Lift your mood, relieve tension, alleviate pain, treat some kind of health condition? Every essential oil contains compounds with unique benefits, but there is no ultimate list of which essential oil is best to address which need or health concern. We encourage you to do your own research and talk to your preferred medical professional before getting started with particular essential oils; in this guide, we will tell about some of the most popular essential oils and how to use them.


Do essential oils work?

Essential oils serve as the plant’s built-in natural protection against insects and harsh environmental conditions. All of these protective and healing qualities have been harnessed and bottled in the essential oils we use today.

The building blocks of essential oils are very small molecules that penetrate your cells. This makes essential oils different from fatty oils (like vegetable oils used for cooking) which have molecules that are too large to penetrate cells so they can’t be used therapeutically. If used correctly, essential oils can have tremendous healing properties.

How do they work?

Essential oils (sometimes also called ethereal or volatile oils) are called “essential” because they are derived from the plant’s active chemical compounds. Each plant has these building blocks, called volatile aromatic compounds (VAC). And every essential oil is basically a liquid containing volatile aroma compounds from plants (which is why essential oils are also known as volatile oils).

Volatile compounds change their state quickly—from a liquid to a gas, for instance. When you open a bottle of essential oil, the aroma is very strong. That’s because the oil is quickly changing to a gas and therefore emitting its aroma into the room and interacting with olfactory sensors in the nose. This is why essential oils are ideal for aromatherapy.

Each plant’s VACs are unique and therefore determine the essential oil’s unique properties, aroma and protective benefits. So far, scientists have isolated over 3,000 VACs in plant species; different species of the same plant can have slightly different VACs, and oil compositions can vary depending on many other environmental factors. The same plant grown in different geographical regions or different weather conditions can have different VACs, for example.

Health benefits of essential oils: what are essential oils good for?

People all over the world use essential oils for a wide range of physical and emotional applications today, just as they have done for thousands of years. Oils are used as single oils or can be mixed with other oils to create powerful and complex essential oil blends.

As testified by those who use them daily for health, beauty and household, the most wonderful thing about essential oils is the various uses you can get out of each one. Lemon oil can be an effective cold and flu remedy (being a great decongestant) while it also makes a nice cleanser for your kitchen counters; lavender is great to aid in sleeping and it can soothe burns, cuts and scrapes as well. Oregano oil can be equally good for fighting colds, keeping your digestive tract healthy, and soothing problematic skin. Nearly all essential oils are versatile like this, with each having multiple uses. Below are only a few examples of possible health benefits!

Anxiety, depression, and stress

Aromatherapy is a real, effective therapy for mood disorders like depression and anxiety. Have you ever had chamomile tea at night to calm down? The essential oils of the plant are in the tea. They work, don’t they? In a recent study conducted in China, scientists performed animal studies involving aromatherapy using Roman chamomile essential oil for two weeks. Amazingly, scientists used imaging to show the inhalation of the VACs “light up” in the hippocampus, the part of the brain that regulates mood.

Certain essential oils like those in the mint family (spearmint, peppermint and others) contain the chemical compound carvone. Brazilian scientists published a recent study showing the significant calming effect of carvone on subjects with anxiety.


Many of these same oils can be used for simple aromatherapy relaxation. It can be as simple as putting a few drops of oil on your hands, and rubbing them together to emit the wonderful smells. Or place oil on a cotton ball and breathe in the aroma. Here’s a guide on a few simple ways to use essential oils at home for relaxation and other everyday needs. Some massage therapists use essential oils during massage; not only are the oils absorbed through the skin, but their aroma is also released into the air for inhalation.


Who among us couldn’t use a better night’s sleep? Poor sleep has downstream repercussions on many other areas of health. For example, dementia patients are very prone to sleep disturbances. A Japanese study used aromatherapy for a 20-day period; oils were put onto a towel left near the patient’s pillow. Subjects slept longer and got better quality of sleep.

Single oils like lavender and chamomile are very effective for sleep, and there are also blended oils designed for sleep that contain lavender, chamomile, and other oils such as cedarwood or vetiver.


Essential oils might be useful in seasonal allergy symptoms. Oils used for respiratory support contain the chemical compound eucalyptol, shown to be very effective in combating the immune system changes that occur with seasonal allergies. Oregano has long been used for respiratory problems, and other oils like cardamom and rosemary are very effective. In a recent study in mice, essential oil compound mixtures showed a great reduction in airway inflammation.

Immune System

Our immune systems suffer a daily onslaught of bacteria, viruses and environmental threats. Add in lifestyle factors of stress and poor sleep, and our immune systems usually do not fare well. Immunity has two parts. The first line of defense protects the body from invader entry; the skin and gastrointestinal tract are good examples. If an invader does happen to get past the first line of defense, we have mobilized immunity that comes to the rescue. White blood cells rush to the infection. Boosting both aspects of the immune system is important in order to stay healthy.

Oregano is powerful for respiratory issues. Clove oil has both anti-bacterial and anti-parasite qualities. A protein called chitin is produced by insects as a waste product.  People inhale it from the circulating air. Chitin is an example of one of the intruders we are exposed to on a daily basis. Scientists studied the effects of peppermint and thyme essential oils on chitin. Amazingly, these oils reversed the negative respiratory effects of chitin. The chitin is still present in the air—nothing can be done about that—but the oils made the cells not have an adverse reaction to it.


Arthritis and Joint Pain

Just as essential oils can calm your senses, they can also calm your muscles and provide relief to your joints. These oils are applied topically right to the painful joint or muscle, and penetrate deeply to relax tissues. Oils like wintergreen and camphor are fantastic, and there are oils blends specifically designed for pain.


One of the biggest health issues nowadays is rampant inflammation. This out-of-control situation wreaks havoc on so many body systems, creating drastic long-term effects. Our bodies are supposed to naturally regulate inflammation, but the daily onslaught to our immune systems usually means that inflammation runs rampant. Certain oils like thyme and oregano have a compound called carvacrol that supports the immune system. A group of scientists in 2015 found that carvacrol kept the body from overproducing the inflammatory molecules that lead to negative effects.

Pregnancy and childbirth

For thousands of years, midwives have used essential oils to ease the pain of pregnancy and delivery. Modern midwives still use these oils for massage, and patients report less anxiety and pain. Many oils are considered safe during pregnancy, especially after the first trimester (depending on the source).

As a doula and essential oil specialist puts it, “While we should respect the power and potency of high-quality essential oils, most can be used safely during pregnancy. Essential oils can help with reducing nausea, stress and anxiousness, supporting the digestive system, lessening back pain, labor and much more. Only use quality oils from a trusted source and always dilute them while pregnant.”

How to use essential oils

Essential oils are used primarily in three ways—topically (applied to the skin directly or diluted in baths, sprays, homemade creams, lotions, body butters and other homemade products), inhaled, or ingested. There are many different kinds of application methods within each of these ways, and the chosen method depends on the essential oil you chose to use and the desired effect.  Some essential oils are safe to use topically while others are irritating to the skin and might better be used by inhalation.

Aromatherapy is probably the most common way to use essential oils. The essential chemical compounds are absorbed into the bloodstream during inhalation. Many people use diffusers to vaporize and dispense the oils. Use lavender for stress relief, lemon for a fresh clean disinfecting scent… The options here are countless!

If you don’t have a diffuser, one solution is as simple as rubbing a few drops on your hands and rubbing them together to release the compounds, or place on a cotton ball and inhale (keep in mind that topical use is not safe with certain oils!) You can also use essential oils in a hot bath; the compounds are then released by the steam.

Oils can be used topically in many ways. Since the VACs are so small, they can easily penetrate the skin and quickly enter the bloodstream. Important note: undiluted use of essential oils on the skin can cause irritation or an allergic reaction. There are some essential oils that are considered safe to use undiluted on the skin, though—unless you are sensitive to them.

With stronger oils, a carrier oil needs to be used to slow down absorption. The carrier oil can also reduce any skin irritation that would occur if the oil were applied full strength to the skin. The most popular carrier oils are coconut, avocado and olive oils. As a general rule, essential oils should be diluted in a carrier oil in a proportion of 3-5 drops of essential oils per teaspoon of carrier oil.

While certain essential oils can be ingested by adding a few drops to  (a lot of) water, it’s generally recognized that there is no need to take essential oils internally to receive the health benefits associated with their use. Before considering to use internally, be sure to read warning labels and make sure your oil is safe for ingestion. Some essential oils are toxic and should be avoided to contact directly. Among those that are (with precautions) safe to ingest, lemon oil water is commonly used due to its cleansing effects and the ability to lower your overall pH (acidity). Peppermint oil can soothe certain digestive issues.

No matter which essential oil and application method you choose, be sure to dilute the oils properly, consider your individual reactions, and watch closely for adverse reactions!

How to store essential oils

Most essential oils come in dark glass containers to keep light out since light and UV rays can change the oils by creating oxidation. Store oils in a cool place to help preserve their potency. Once opened, most oils can be safely used for one to two years, and later they may see a reduction in potency; other oils will last for as long as 5-10 years without

Essential oil contraindications

Certain oils can affect hormone levels, so as a precaution should not be used during pregnancy: basil, cinnamon, clary sage, clove, cypress, fennel, jasmine, juniper, marjoram, myrrh, rose, rosemary, sage and thyme.

Other precautions have to do with your personal needs, reactions and health concerns, so, as mentioned above, be sure to:

  • Consider your individual reactions: if you’re allergic to the plant, avoid its essential oil as well! It’s wise to always conduct a skin test before beginning topical use of a new essential oil.
  • Watch closely for adverse reactions (depending on the application method it can be irritation or swelling of the skin, itchiness, hives, rash, digestive issues, difficulty breathing). If you find you are sensitive to a particular essential oil, do not use it in the future. Seek medical attention if the adverse effects are moderate or severe.

Choosing the best oils

The U.S. FDA does not regulate essential oils, so it is important to find reputable distributors. Good quality oils should have a clear statement about purity. The label should be clear whether the product is 100 percent essential oil or whether it’s been diluted. Compare costs of several brands of the same oil; the really inexpensive ones are probably not real.


The best 10 oils and what are they best for

  • Bergamot has a citrusy aroma that is great for elevating mood and healing skin
  • Clove oil has a warm and woodsy scent and is great for pain relief and inflammation
  • Eucalyptus oil is a great decongestant and is good for topical pain relief
  • Frankincense is one of the oldest oils in the world,  used for its anti-microbial and anti-inflammatory properties
  • Lavender is a great sleep-inducing and calming oil
  • Lemon oil is a great air freshener, household cleaner and anti-fungal
  • Oregano is wonderful for skin conditions like eczema and psoriasis
  • Peppermint is used to ease digestion and headaches, joint and muscle pain
  • Rosemary is a great internal detoxifier and can be used for skin conditions
  • Tea tree oil (as well as thyme and ginger) fight symptoms of colds and flu


At the end of the day, essential oils can be a great addition to your life and health, as long as they are used safely.

Thanks to their anti-inflammatory, antimicrobial and antioxidant properties, they are rapidly growing in popularity for health and wellness practices all around the world. Today, essential oils are part of so many products on the market: creams, lotions, shampoos, lip balms, toothpastes—and many people make their own blends and mixtures at home to be used as beauty products as well as air fresheners, household cleaners, even bug sprays—and so much more!

Will you be the next person to try essential oils?

Use them with care and respect and you will receive a variety of health benefits!