What's the deal with essential oils?

So what are essential oils anyway?

Essential oils are a concentrated extraction of the volatile oils from plants.

These oils are considered "volatile" because they evaporate easily at normal temperatures. The term “essential oil” is technically a misnomer because chemically speaking, they are actually a complex mixture of alcohols, terpenes, phenols, esters, and ketones, rather than an actual “oil”.

They are referred to commonly as an oil simply because they tend to behave as an oil. They have a low solubility in water, and will float on the surface past about a 4% dilution.

Hydrosols have about a 4% essential oils content, if more is added it will begin to accumulate on the surface.

The plant produces these oils to attract pollinators, repel predators, kill invading bacteria and fungus, or to block the intense sun by releasing a cloud of essential oils around the plant during the hottest portions of the day. Depending on the plant, the purpose can vary greatly.

Essential oils are about 75-100X more powerful than dried herbs. On average 1 oz (30 g) of plant will yield 1 drop of essential oil. In some cases such as roses, it takes roughly 60 000 roses to produce 30 ml of essential oil! This explains the higher cost of some oils compared to others. Some plants like lavender produce a lot more essential oil per plant and are therefore much cheaper to purchase. 



Humans have been using aromatic plants for thousands of years. Ancient application was mainly ritualistic in various religions, as well as to arouse sexual desire, and to generally improve quality of life. For example, the ancient Egyptians were well versed in the use of aromatic plants, and it was adopted as a way of life for them. The Perfumes, medicines, and  spices for cooking were common practice. Some of the rarer aromas like cinnamon and clove were highly regarded and reserved for only the most noble.

Many oils were used in the embalming process for treating dead royalty as well. They were thought to be the incense of the Gods. The smoke was used to attract good influences and repel evil.

(Hofacker, 2016)

(Hofacker, 2016)

Alchemists in the middle ages made good use of essential oils from plants through sophisticated distillation processes to extract the "life essences” of plants. These distillation practices are what have led to the modern day techniques of extraction.

When essential oils in the form of aromatherapy came to Europe, they were used primarily in perfumes, but also in medicine. By 1190, the use of essential oils in perfume-making was so advanced, that King Philip Augustus developed guidelines requiring perfumers to train for 4 years and be tried by a jury before exercising their skills. They took it very seriously. The Renaissance saw a surge in herbology and expanded the use of essential oils to cosmetics. 

It was noticed during times of plague, that herb growers and perfumers were surviving the plague at a higher rate than the rest of the population. This was thought to be due to the antibiotic effects of many of the aromatic volatile oils.

Not everybody supported the use of aromatics however. In 1760, King George III of England proclaimed that women who seduced men through the use of scent could be thrown in jail for sorcery.


Whats Happening With Them Today?

Today, aromatherapy is widely used in massage therapy, skin care, psychology, hypnotherapy, and by chiropractors, herbalists, as well as home treatment. It is a recognized practice by many naturopaths in Canada, America, and Australia. Though North America is still lagging behind Europe in the use, research, and development of essential oils. Suppliers and users are growing rapidly however, and it is likely that it will one day become a part of mainstream medicine once again as the chemistry is analysed and tested further. 

(Johnson, 2014)

(Johnson, 2014)

How Do They Work?

It is well documented that our sense of smell is over 10 000 times more sensitive than some of our other senses [1]. These oils produce effects through what is called the limbic system (referred to as the smell or primal brain). This system is one of the most ancient parts of our brains, remaining unchanged for over 20 000 years in human evolution.  It drives such things as hunger, sexual attraction, the endocrine system, the autonomic nervous system, emotions, and plays a role in memory.

There are also physical actions through ingestion, or topical application of essential oils. The volatile oils contained in plants are extremely complex and produce a wide range of actions.

Photo credit: Noli, C. (2015)

Photo credit: Noli, C. (2015)


+ Terpenes

End with "ene".

produced mostly by conifers, but also by other plants, and some insects such as termites.

A class of hydrocarbons. the difference between them and terpenoids is simply that terpenoids have other functional groups attached.

They are a mojor component of resin.

Terpenes are biosynthetic building blocks within nearly every living creature.

A solvent. Can dissolve mucous in the lungs simply by inhalation.

Bisabolene - Black pepper, Carrot seeds, Fir, Lemon

Camphene - Black pepper, camphor and Borneone, Citronella, Cypress, Eucalyptus globulus, Fennel, Fir, Frankincence, Ginger, Hyssop, Lavandin, Lemon, Myrtle, Neroli, Nutmeg, Petitgrain, pine, Rosemary.

Camphrene - Juniper

Carene - Galbanum

Cymene - Cinnamon, Coriander, Cumin, thyme, Tea tree

Dipentine - Cajeput, Camphor and Borneone, Cinnamon, Citronella, Coriander, Cumin, Fennel, Fir, Frankincence, LavandinLemon, Myrrh, Myrtle, Nutmeg, Palmorosa, Pine, Rosewood, Verbena.

Fenchene - Eucalyptus globulus

Heerabolene - Myrrh

Limonene (all citrus oils 90%+) - Angelica, Bay, Black pepper, Cajeput, Cardamom, Carrot seeds, Celery, Caraway, Citronella, Dill, Fennel, Galbanum, Ginger, Lavandin, Lavender, Lemon, Lime, Litsea, Cubeba, Lemongrass, Myrrh, Neroli, Niaouli, Palmarosa, Petitgrain, Peppermint, Spearmint, Verbena, Yarrow.

Myrcene (mercene) - Bay, Black pepper, Galbanum, Juniper, Lemongrass, Rose Spearmint, Verbena.

Ocimene - Lavandin, Tarragon

P. Menthadienes - Therebentine

Phellandrene - Angelica, Bay, Black Pepper, Cinnamon, Coriander, Cumin, Dill, Eucalyptus globulus, Fennel, Fir, Frankincence, Ginger, Lemon, Peppermint, Pine, Sage, Spearmint, Terragon

Pinene - Angelica, Basil, Bay, Black pepper, Cajeput, Carrot seeds, Cinnamon, Cloves, Coriander, Cumin, Cypress, Eucalyptus globulus, Fir, Frankincence, Galbanum, Grapefruit, Hyssop, Helichrysum, Lavender, Lemon, Lime, Marjoram, Myrrh, Myrtle, Niaouli, Nutmeg, Oregano, parsley, Pine, Rosemary, Spearmint.

Alpha pinene - Juniper, Pine

Piperene - black pepper

Sabinene - Black Pepper, Cardamom, geranium, Juniper, Lime, Listea, cubeba, Marjoram

Selenine - Celery

Sylvestrene - Cypress, Pine

Terpenine - Cardamom, Coriander, Dill, Lavandin, Marjoram, Thyme, tea tree

Terpinolene - Coriander, Galbanum, lime

Vetivene - Vetiver

+ Sesqui-Terpenes:

End with "Ene"

Cadinene - Cedarwood, frankincence, Galbanum, Hyssop, Juniper, Lemon, Litsea, Cubeba, Myrrh, Patchouli, Pine, Ylang Ylang.

Caryophyllene [Sedative, anti-carcinogenic] - Black pepper Clary sage, Cloves (10%), lavandin, Lavender, Marjoram, Melissa, Rosemary, Spearmint, thyme, Tea tree, Yarrow, Ylang Ylang.

Cedrene - Cedar, Juniper

Chamazulene (or azulene) [Anti-inflammatory] - All chamomiles (in varying percentages), tansy, Yarrow.

Santalene - Sandalwood

+ Alcohols:

End with "Ol".


Can be used neat

Uplifting fragrances

Bisabolol - German chamomile

Borneol (similar to camphor) - Angelica, Camphor and borneo, Cardamom, Coriander, Citronella, Galbanum, Ginger, Hyssop, Juniper, Lavender, Marjoram, Pine, Rosemary, Sage, Thyme, Verbena, Yarrow.

Carotol - Carrot seed

Cedrol - Cedarwood

Citronellol - Citronella, geranium, Melissa, Palmorosa, Rose

Farnesol - Chamomile, Jasmine, Lemongrass, Palmorosa, Rose, Ylang Ylang.

Geraniol - Bay, Citronella, Coriander, Geranium, Grapefruit, Helichrysum, Jasmine, Lavender, Litsea Cubeba, Lemongrass, Melissa, Myrtle, Neroli, Nutmeg, Palmorosa, Petitgrain, Rose, Rosewood, Verbena, Ylang Ylang.

Guaiol - Galbanum

Lavendulol - Lavendin, Lavender,

Linalol - Angelica, Basil, Bay, Bergamont, Cinnamon, Clary sage, Coriander, Galbanum, Geranium, Grapefruit, Helichrysum, Hyssop, Lavandin, Lavender, Lemon, Lime, Litsea cubeba, Melissa, Myrtle, Neroli, Nutmeg, Peppermint, Petitgrain, Rosewood,(90%), Spike, Thyme (lemon and sweet), Verbena, Ylang Ylang.

Menthol - Peppermint

Myrtenol - geranium, Myrtle

Nerol (includes nerolidol) - Bergamont, Citronella, Helichrysum, Jasmine, Lemongrass, Myrtle, Neroli, Orange, Petitgrain, Rose, Rosewood, Verbena

Olibanol - Frankincence

Ormenol - Chamomile mixta

Patchoulol - Patchouli

Sabinol - Cypress

Salviol - Sage

Santalol - Sandalwood

Terpineol - Bay, Bergamont, Cajeput, Cardamom, Coriander, Eucalyptus globulus, Galbanum, Geranium, Jasmine, Lavandin, Lavender, Lime, Marjoram, Niaouli, Nutmeg, Petitgrain, Rosewood

Terpinen.4.ol (or terpineol 4) - Juniper, Marjoram, tea tree

terpinen.5.ol - Juniper

Alpha-terpineol - Cajeput, Cardamom, Eucalyptus radiata, Niaouli, tea tree

Vetivol - Vetiver

Ylangol - Ylang Ylang

+ Phenols:

End with "Ol".

Complex alcohols.

Extremely Strong! Use CAUTION.

Strongest anti-infectious agents

Too harsh to use neat on skin

Immune stimulants (but use with CAUTION due to liver toxicity).

Carvacrol - Horsemint (monarda fistulosa), Peppermint, Oregano, Savory, thyme

Thymol - Horsemint, Oregano, Red thyme

+ Oxides:

End with "Ole".

Affects Bronchioles. Especially cineol, working to stimulate active mucous glands in the lungs.

Ascaridole - Chenapodium (goosefoot family).

Eucalyptole (cineol) - Basil, Bay, Cajeput, Clary sage, Coriander, Eucalyptus,globulus (70%), Ginger, Laurel, Lavender, Lavandin, Litsea cubeba, Myrtle, Niaouli, Rosemary, Rosewood, Sage, Spearmint, Tea tree, Yarrow,

Indole (nitrogenous) - Neroli

Linalol Oxide - Hyssop

Limonene Cineole - Cardamom

+ Aldehydes:

End with "Al".

Calming, Soothing, Sedative.


Can be antiseptic

Anisic Aldehyde - Aniseed, Fennel

Benzaldehyde - Cajeput, Cinnamon, Patchouli

Citral - Citronella, Geranium, Ginger, Grapefruit, Lemon, Lime, Lemongrass, Lemon Verbena, Lemon thyme, Litsea cubeba, Melissa, Petitgrain

Citronellal - Citronella, eucalyptus,citriadora, Lemon, Lemongrass, Litsea cubeba, Melissa

Cinnamic aldehyde - Cinnamon (80-95%), Myrrh, Patchouli

Cuminic Aldehyde - Caraway, Cumin, German Chamomile, Fennel, Myrrh, Rosemary

Furfurol - Caraway, Cinnamon, Cloves, Cypress, Sandalwood, Vetivert,

Geranial - Geranium

Myrtenal - Myrtle

Neral - Neroli

+ Ketones:

End with "One".

Great on the skin (cytophylactic).

Great wound healer (vulnerary).

Strong mucolytic and lipolytic.

CAUTION: Many ketones must be avoided altogether or used sparingly during early pregnancy, with children, or for any internal use.

Asarone - Carrot seed

Atlantone 7 - Cedarwood

Borneone - Basil

Camphor(includes camphenone) - Basil, Camphor, Hyssop, Lavandin, Marjoram, Rosemary, Rosemary, Sage, Spike

Carvone (pino-camphone) - Caraway, Dill, Galbanum, Hyssop, Peppermint, Spearmint(55%)

D.Fenchone - Fennel (20%)

Irone - Violets

Jasmone - Jasmine, Neroli, Peppermint

Lactone - Angelica, Bergamont, Celery, Lime,(bergaptene), lovage

Menthone - Geranium

Piperitone - Eucalyptus, peppermint

Pulegone - Pennyroyal, Peppermint

Thujone - Hyssop, Mugwort, Sage, Tansy, Thuja, Wormwood (artemesia).

Verbenone - Rosemary

Vetivone - Vetiver

Zingiberone - Ginger

+ Esters:

End with "Ate".

Affect central nervous system.



Can be antifungal

Roman Chamomile (nobilis) is king of this class.

Allyl Isotheocyanate - Mustard

Benzyl Acetate - Jasmine, Ylang Ylang

Bornyl Acetate - Fir, Pinus, Rosemary (2-6%)

Geranyl Acetate - Lavender, Melissa, Palmorosa, Petitgrain

Lavandulyl Acetate - Lavender

Linalyl Acetate - Bergamont (35-45%), Clary sage, Jasmine, Lavender (35%), Lavandin, Lime, Litsea cubeba, Neroli, Petitgrain

Methyl Anthranilate - Jasmine, Neroli, Orange

Methyl Salicylate - Birch, Cloves, Wintergreen

Menthyl Acetate - Peppermint

Neryl Acetate - Helichrysum, Neroli

Terpenyl Acetate - Cypress, Fir, Pine

+ Phenolic Esthers:

End with "Ol".

Similar to esters, but stronger analgesics.

Severe skin reactions.

Anethol - Aniseed, Basil, Fennel (50-60%)

Apiol [Abortivacient] - Parsley

Charvicol - Bay

Methyl Chavicol - Aniseed, basil, Fennel, Tarragon

Eugenol - Basil, Bay, Black pepper, Cinnamon leaf, Cloves (85%), Dill, Geranium, Jasmine, Myrrh, Nutmeg, Patchouli, Rose, Ylang Ylang.

Myristicin [Hallucinogenic] - Black pepper, Dill, Nutmeg, Parsley.

Safrol - Black pepper, Camphor, Cinnamon, Nutmeg, Sassafras (80%), Star anise, Ylang Ylang.

+ Basil

Contains phenylpropanes (anything licoricy has this chemical) that acts as an anaesthetic. Useful for convulsions, deep hard coughs, bug bites, stress related allergies, headaches, nerve tonic, uplifting depression, any sort of spasm. Can improve studying by deep breathing. Do not use more than 1 drop on the skin. Dissolves uric acid chrysalis (stones), helps achieve a regular menstral cycle for women. Middle note aroma.

+ Bergamont

Sedating, makes your skin photosensitive (due to bergaptin). Some forms (FCP) are not but are also not as medicinal. This oil is antibiotic, antiviral, calming. It is used for anorexia, anxiety, and preparing your body to eat by stimulating drool. Described aromatically as a soft top note resembling a light citrus.

+ Birch

Contains Methyl salicylic acid. This chemical has been made famous by Aspirin. It is pain killing. Top note aroma.

+ Cardamom

Top Note aroma. Modifier.

+ Catnip

Very good mouse repellant contains ketones called Nepata lactones. these lactones can be harmful, so caution must be observed during use. Does not have a good aroma.

+ Cinnamon

Top note aroma. Modifier.

+ Citrus Fruits

Emotionally uplifting, bright, happy, astringent, high in terpenes, used to cheer people up, also useful in jet lag, grogginess, pregnancy, and depression. Lime is the cheapest of the citrus fruit essential oils.

+ Clary sage

Hormone balancing (internally or aroma), works great for women but also affects males positively. Very calming, if doing some writing or drawing or anything creative as such and you run out of creativity, clary sage is said to help with that.

+ Clove

Powerful infection fighter and anodyne. Useful orally after brushing teeth. Good for any infection, or pain due to infection, teething babies, lung remedies, diarrhea, digestive infections, and parasite blends.

+ Cypress

One of the most astringent essential oil. Woody smell but not the most pleasant. Bass note.

+ Elemi

Great in meditation blends.

+ Eucalyptus globulus

Contains terpenes, oxides, and ketones, (no alcohol like radiate). makes a better cleaner for households than radiate as it is much stronger.

+ Eucalyptus radiata

Most common, contains terpenes, oxides, and alcohol.

+ Frankincense

Prevents skin cancer, meditative, some naturopaths use it to treat prostate cancer. useful in meditative blends, skin care, and rejuvenating skin blends to protect and restore skin, especially from radiation damage.

+ Grapefruit

Astringent and uplifting. Top note aroma.

+ Honey Myrtle

A type of Melaleuca. Contains aldehydes which give it calming properties.

+ Hyssop

High in Ketones, Used for Cold sores, antiviral.

+ Jasmine

Sensai calls it "sex in a bottle". Grandiflora is the most common species, too much smell faecal however. Related to Lilacs, Very expensive oil and often comes diluted to 10%. Stimulates endorphins creating a runners high, and boosts immunity as well as overall general health. The flowers are picked before sunrise to avoid oxidation. It is a true aphrodisiac in every sense of the word, is boosts sperm counts, and helps milk production.

+ Juniper berry

Useful for lymphatic detoxification, as well as for circulation. Middle note aroma.

+ Lavender

Sedating, calming, a staple in essential oil stock, analgesic, burns, insect bites, lowers stress induced hypertension, cuts, antibiotic, headaches due to chinook pressure changes, repels insects such as bed bugs, sedating. Contains esters. Top note aroma.

+ Lavandin

recommended to run through a gas chromatogram because of inconsistencies with this herb. Cheaper than lavender, therefore it is widely used in soap making and perfumes.

+ Lavender stoechas

Specialty oil. Can cause headaches due to ketone content.

+ Lemon

Top note aroma.

+ Lemongrass

Familiar lemony aroma. Has an affinity for the breasts and is also very good for connective tissue.

+ Lime

Top - Middle note.

+ Marjoram (Oreganum marjoram)

Great for ear infections, muscle blends, and toadd warmth. Marketed as treatment for snoring, my Sensai says any leaf oil will accomplish this. To do this put 1-2 drops in your hands and hold over the face for a few breaths. Egyptian marjoram is high in alpha-terpenin-4-ol which is also found in tea tree oil and is well known as a powerful infection fighter.

+ Melissa

Antiviral, very calming, good to use during anxiety, grief, and stress. This oil is very expensive. It is best steam distilled in small batches.

+ Monarda fistulosa (Horse mint)

Smells like oregano because it contains a common ingredient. Powerful infection fighter. Be aware of hybrids that do not have the same medicinal value. Garden centers sell the hybrids generally because they are generally much larger and prettier, however, these are often not the same medicinally.

+ Myrrh

Meditative, bitter, astringent, antibiotic. Useful in strengthening gums by keeping them firmans works on cancer sores, useful in vaginal infections and urinary tract infections (UTI). Also a skin preservative.

+ Myrtle

only 1 species. Useful for compromised lungs in fragile person. It is a gently lung cleanser, useful in lowering stress induced hypertension. Related to Eucalyptus. The hydrofoil can be used directly in the eye for conjunctivitis as well as allergies affecting the eye. Middle note aroma.

+ Neroli

useful in insomnia, menopausal symptoms, as a euphoric, and to strengthen the hearty chakra.

+ Orange

Astringent. Top note aroma.

+ Patchouli

A heavy essential oil that does not evaporate as quickly as most essential oils. Perfect companion herb for cannabis. Covers most negative smells. Very astringent, used on snake/scorpion bites. It is an aphrodisiac and turns off appetite. Useful as a natural deodorant, and makes a great base note for perfumes due to its heaviness and ability to evaporate slowly. Bass note.

+ Pennyroyal

High in Ketones. Used for clogged fallopian tubes, abortifacient, bug repellant.

+ Peppermint

Stimulates the thyroid which in turn affects metabolism. Great for digestive complaints at 1 drop orally. Good at adjusting temperature due to thyroid stimulation, also useful for jet lag, fainting, any stomach/digestive complaints such as car sickness, indigestion, or stomach flu. Used on bug bites, in lymphatic blends, and sunburns (1 drop for whole burn spot). Be careful when using on rashes as high concentrations can cause more irritation. Top note aroma. Modifier.

+ Petitgrain

Used similarly to eucalyptus, anti-inflammatory, soothing for the lungs. The aroma can be described as a bass note.

+ Ravensara

Similar chemical profile to eucalyptus.

+ Rose

raises semen production, revitalizes mature skin, improves microcirculation, and is an aphrodisiac. Rose hydrosol is said to be a cure for hangovers simply by drinking.

+ Rosemary

Top note aroma. Circulatory stimulant.

+ Rosewood

Middle note aroma.

+ Sandalwood

Soft bass notes in the aroma.

+ Spearmint

Soft, warm action. Very gentle oil. Great if used in blends.

+ Spike Lavender

Cheaper than lavender due to being a bigger plant therefore producing more oil. Contains no lanalyl-acetate (which Lavender angustifolia does) so has no sedating effect. Very gentle, great for sinus trouble, can be used at 1 drop inside the er canal, however be careful when doing this with essential oils.

+ Tarragon

Useful as a Helichrysum substitute in wound healing. Has some anti-allergenic qualities. Sense believes this has something to do with mast cells. It will only have noticeable effect if used before subjected to the allergen. Middle note.

+ Tea tree

Antibiotic, anti parasitic, anti fungal. Useful with food poisoning (with cinnamon also), can be used as a suppository, can be used as a douche diluted.

+ Thyme (red)

Very antibiotic, heating, and improves penetration of other oils into the skin or digestive tract.Top note aroma.

+ Vanilla (absolute)

Stimulates vaginal secretions. In small amounts this acts as an aphrodisiac, however in high amounts it can be too sweet and may cause nausea. are must be taken if using in blends so as not to use too much and wreck the blend. It is very dark and due to being an absolute contains pigment. Vanilla absolute sometimes does not mix well with other oils, To aid in dissolving, mix with slightly warmed oil and shake rapidly. This usually is enough to hold vanilla in suspension for a long long time. Bass note aroma.

+ Vetivert

Bass note aroma.

+ Ylang ylang

Bass note aroma.



Though essential oils can be a great tool medicinally, and a positive influence emotionally, some precautions must be noted. Since essential oils are so highly concentrated, using large amounts at one time can be hazardous. Cinnamon for example can burn the skin when in high concentrations. These simple precautions must be considered when using essential oils:

  1. When using essential oils in the bathtub avoid getting vapours or bath water in your eyes.

  2. All essential oils must be kept away from children.

  3. Some essential oils such as thyme or eucalyptus must be used in small concentrations (3-4 drops). Know what the dangers are of the oils you are using or simply use less dangerous ones.

  4. If too much oil is applied or some has gotten into the eye, use an oil to remove, NOT WATER!! The essential oils are all soluble in oil and repelled by water. If you try to wash away essential oils with water it will just make the situation worse. Use vegetable oil and wipe it off with a cloth, this will dilute the concentration of the essential oils, and is the most effective home treatment.

  5. In general, it is best to use essential oils in low concentrations, which can be achieved by using only a few drops at a time (1-4), or by diluting into a carrier oil such as coconut or sweet almond oil, before using it on your skin.

Justin Cooke @JuzzieCooke

The Sunlight Experiment @TheSunlightExp


  1. BBC. (2014, September). BBC Science & Nature - Human Body and Mind - Nervous System Layer. Retrieved from http://www.bbc.co.uk/science/humanbody/body/factfiles/smell/smell_animation.shtml

  2. Hofacker, B. (2016). Raw Organic Cardamom Pods Ready to Use [Photograph]. Retrieved from https://www.flickr.com/photos/97092379@N04/24337312623/

  3. Johnson, K. (2014). Glass medicine vial and spoon on white background [Photograph]. Retrieved from https://www.flickr.com/photos/44509107@N03/23707363353/

  4. Noli, C. (2015). minimal food photography clara noli UK Italy [Photograph]. Retrieved from https://www.flickr.com/photos/124753421@N07/23655265469/

  5. Reling, C. (2015). Dried lavender herb and essential aromatherapy oil [photograph]. Retrieved from https://www.flickr.com/photos/132609512@N05/21097391573/