Essential oils: benefits, properties, and how to use them
Everything you need to know about essential oils: what they are, how they act on the body and mind, the 15 most used in aromatherapy, and how to choose them consciously.
Reading time: approx. 20 minutes · Category: Aromatherapy
Essential oils have entered the homes and routines of millions of people worldwide, yet they often remain shrouded in an aura of mystery. Are they miraculous remedies? Are they simple perfumes? The reality, as always, is more nuanced and more interesting.
This guide was created with a precise objective: to offer you a complete, honest, and scientifically founded overview of the world of essential oils. You will find clear explanations of what they are, how they act on the body and mind, the 15 most versatile oils, the most effective usage methods, and everything you need to know to use them with awareness and safety.
Whether you are a beginner or already have some experience with aromatherapy, this guide is designed to be a lasting reference: to consult whenever you want, to keep close at hand.
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What essential oils are
Essential oils are natural aromatic concentrates extracted from plants, flowers, leaves, barks, roots, seeds, or resins. Despite the name, they are not "oils" in the fatty sense: they are volatile liquids, almost always transparent or lightly colored, and they evaporate quickly on contact with air.
The term "essential" does not refer to food use but to the idea of essence: the aromatic and biologically active quintessence of the plant. Each essential oil is a concentrate of organic molecules—terpenes, esters, alcohols, ketones, oxides—that the plant produces to communicate, defend itself, attract pollinators, or protect itself from pathogens.
How they are extracted
The most common extraction method is steam distillation: water vapor passes through the plant material, carrying aromatic molecules with it, then cools and separates from the essential oil due to density difference. This method preserves the chemical complexity of the oil without altering its properties.
For citrus fruits (lemon, orange, bergamot), cold pressing of the peel is used, which preserves the fresh and vibrant notes typical of these oils. Precious resins like frankincense require delicate distillation, while more fragile flowers—such as rose or jasmine—are often processed with solvents or by the enfleurage method.
Essential oil vs. fragrance oil
It is crucial to distinguish a pure essential oil from a fragrance oil or synthetic fragrance. Fragrance oils are mixtures of synthetic chemical substances, often low-cost, that imitate an aroma but do not possess the same bioactive characteristics as natural essential oils. Always look for the botanical Latin name and the wording "100% pure" or "natural" on the label.
I have written a dedicated article: how to recognize a pure essential oil.
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How essential oils work
To understand why essential oils can truly influence our mood, stress level, or sleep quality, we need to take a brief journey into the neurology of smell.
The role of smell
Smell is the oldest sense from an evolutionary perspective. Unlike other senses, the olfactory pathway bypasses the thalamus—the brain's "filter"—and goes directly to the limbic system, the region of the brain that manages emotions, memory, motivation, and some basic bodily functions.
When we inhale an essential oil, the aromatic molecules stimulate the olfactory receptors in the nose. The signal is transmitted through the olfactory nerve to the olfactory cortex and, from there, reaches the amygdala (center for emotional responses), the hippocampus (memory), and the hypothalamus (regulation of sleep, appetite, body temperature) in a few moments.
The limbic system and aromatherapy
This direct connection between smell and the limbic system explains why a scent can immediately evoke a memory, change our mood in a few seconds, or make us suddenly feel at home. Aromatherapy consciously leverages this neurological pathway to support emotional states and mental well-being.
I have written an in-depth article on the topic: the limbic system and the link between smell and emotions.
When oils are applied to the skin, smaller molecules can cross the skin barrier and enter the bloodstream, reaching various body tissues. This is the principle behind aromatherapy massages.
Discover the 8 Aromatypes and your personal aromatherapy profile.
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The main benefits of essential oils
Essential oils offer a wide spectrum of potential benefits, which vary depending on the oil, the method of use, and the individual characteristics of the user. It is important to remember that they are not medicines and do not replace medical treatments: they are tools to support well-being, to be integrated into a conscious lifestyle.
Relaxation and stress management
Among the most studied benefits of essential oils is their potential effect on the nervous system. Oils like lavender, bergamot, and vetiver are traditionally chosen to accompany moments of tension, promote a sense of calm, and support emotional well-being during stressful periods. They are particularly appreciated during relaxation sessions, in the evening, or at the end of a busy day.
Diffused in the environment during a meditation session, yoga, or simply a break, they create a sensory framework that helps the mind slow down and the body relax.
Improving sleep
Lavender is the most sought-after oil for sleep quality: several preliminary studies suggest that its inhalation before sleep can reduce the time needed to fall asleep and improve sleep quality. Sandalwood, vetiver, Roman chamomile, and cedarwood are also often used in evening routines to promote pre-sleep relaxation.
A diffuser placed in the bedroom, started 30 minutes before bedtime, can become part of an evening ritual that signals to the body that it's time to rest.
Concentration and mental clarity
On the opposite side of relaxation, some essential oils are known for their stimulating and invigorating properties for the mind. Rosemary, peppermint, and lemon are traditionally associated with increased clarity, mental alertness, and concentration.
Diffused in a study or work area during the morning, they can support productivity without the side effects of caffeine. Particularly appreciated by students, professionals, and anyone who needs to keep their mind fresh during long work sessions.
Digestive support
Some essential oils are traditionally used for digestive system well-being. Cardamom, fennel, peppermint, and ginger are among those most often used to aid digestion, relieve bloating, or alleviate mild nausea. Topical application (always diluted in a carrier oil) on the abdomen with circular movements is the most common method for this purpose.
Respiration and seasonal colds
Essential oils rich in 1,8-cineole—such as eucalyptus, ravintsara, and cineole rosemary—are traditionally used to promote free breathing during periods of cold, nasal congestion, or seasons when the respiratory tract is more strained. Inhalation through steaming (a few drops in hot water, with a towel over the head) is one of the most effective and immediate methods.
Skin care
Several essential oils are used in natural cosmetics and skin care. Tea tree is widely known for its sanitizing properties and is used for imperfections. Geranium is appreciated for balancing sebum production. Lavender is often applied to soothe irritated skin or after mild sunburn.
Remember: essential oils should never be applied undiluted to the skin. They should always be diluted in a carrier oil such as sweet almond, jojoba, or argan.
Hair care
In hair cosmetics, oils like rosemary, cedarwood, and lavender are added to shampoos, conditioners, or masks to support scalp health, reduce dandruff, and—in the case of rosemary—promote circulation in the hair follicle. Scalp massage with a mixture of carrier oil and a few drops of essential oil is a well-established practice in traditional natural cosmetics.
Scenting and purifying the environment
One of the most immediate and accessible uses is simply to create a pleasant and personal olfactory atmosphere at home. Unlike synthetic air fresheners, pure essential oils do not contain phthalates, harmful VOCs, or synthetic allergens. Some oils—such as lemon, tea tree, and eucalyptus—are traditionally used to contribute to air freshness in home environments, especially during winter.
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The 15 most used essential oils
Let's explore the fifteen most popular essential oils in aromatherapy: for each, you will find its main properties, common uses, and recommended application methods.
🌿 1. Lavender (Lavandula angustifolia)
Relax · Sleep · SkinMain properties: traditionally used to promote relaxation, support sleep quality, and soothe sensitive skin.
Uses in aromatherapy: moments of tension and stress, evening routines, minor skin irritations, tension headaches.
- Evening diffusion (30–40 minutes before bed)
- Diluted in jojoba oil for relaxing massages
- A few drops on your pillow or linen
🍋 2. Lemon (Citrus limon)
Energy · Purification · MoodMain properties: toning, air purifying, antioxidant, deodorizing, energizing.
Uses: mental fatigue, purifying environments, natural home cleaning, concentration support.
- Morning diffusion to start the day
- A few drops in DIY household cleaners
- Caution: photosensitizing, avoid sun exposure after topical use
🌳 3. Tea Tree (Melaleuca alternifolia)
Hygiene · Skin · FreshnessMain properties: traditionally used for impure skin care, for home hygiene and to contribute to the freshness of environments.
Uses in aromatherapy: skin imperfections, skin care routine, natural home cleaning, scalp care.
- Topical application on imperfections (diluted 1:1 with carrier oil)
- Added to shampoo for the scalp
- Diffusion to sanitize the air at home
🌱 4. Peppermint (Mentha × piperita)
Concentration · Digestion · FreshnessMain properties: mental stimulant, refreshing, anti-nausea, decongestant, mild analgesic.
Uses: fatigue, headache (application to temples, highly diluted), nausea, digestion support, concentration.
- Direct inhalation from the bottle for sudden nausea
- Diffusion during work hours to maintain clarity
- Avoid near infants and young children
🌿 5. Rosemary (Salvia rosmarinus)
Memory · Hair · VitalityMain properties: traditionally used to promote mental concentration, support scalp vitality, and accompany states of fatigue.
Uses in aromatherapy: moments requiring focus and clarity, hair care, muscle fatigue.
- Diffusion during study or work sessions
- Added to scalp massage oil
- Avoid during pregnancy and in cases of hypertension
🌿 6. Eucalyptus (Eucalyptus globulus / radiata)
Respiratory tract · Freshness · VitalityMain properties: traditionally used to promote free breathing and to contribute to the freshness of domestic environments during cold periods.
Uses in aromatherapy: seasonal nasal congestion, domestic environments in winter, fumigations for the respiratory tract.
- Fumigations (4-5 drops in hot water, inhale under a towel)
- Diffusion in rooms in winter
- E. radiata is gentler and preferable for children over 6 years old
🍊 7. Bergamot (Citrus bergamia)
Mood · Lightness · BalanceMain properties: often chosen in aromatherapy to accompany difficult emotional states, promote a feeling of lightness and support mood balance.
Uses in aromatherapy: moments of low mood, agitation, difficulty "switching off" from thoughts.
- Diffusion in the afternoon to balance emotions
- Diluted in oil for solar plexus massage
- Use the FCF version (furanocoumarin-free) for skin use and avoid the sun
🌾 8. Frankincense / Olibanum (Boswellia sacra / carterii)
Meditation · Breath · SpiritualityMain properties: traditionally used to promote slower, deeper breathing, accompany mental presence, and support well-being during moments of introspection.
Uses: meditation, contemplative practices, deep breathing, mature skin care.
- Diffusion during meditation or yoga
- Diluted in carrier oil for skin care
- Direct inhalation for moments of acute anxiety
🌿 9. Vetiver (Chrysopogon zizanioides)
Grounding · Stress · InsomniaMain properties: deeply calming, "grounding," anxiolytic, promotes deep sleep.
Uses: rumination-induced insomnia, chronic anxiety, feeling of disorientation, mental overstimulation.
- Evening diffusion in small quantities (it has an intense and earthy aroma)
- Diluted application to wrists and soles of feet
- Excellent as a base in relaxing blends with lavender and sandalwood
🌸 10. Geranium (Pelargonium graveolens)
Skin · Mood · Female well-beingMain properties: traditionally used for the care of oily skin, to accompany moments of emotional fluctuation and for general female well-being.
Uses in aromatherapy: mixed skin care routine, moments of emotional imbalance, well-being during the menstrual period.
- Diffusion to balance mood during PMS
- Added to creams or serums for daily skin care
- Abdominal massage (diluted) for menstrual cramps
🌿 11. Cardamom (Elettaria cardamomum)
Digestion · Energy · ClarityMain properties: carminative, digestive, toning, mental stimulant, warming.
Uses: difficult digestion, abdominal bloating, fatigue, lack of morning motivation.
- Circular abdominal massage (diluted) after heavy meals
- Morning diffusion in blends with oranges and lemon
- Added to preparations for warming aromatic baths
🌿 12. Fennel (Foeniculum vulgare)
Digestion · Detox · BloatingMain properties: carminative, mild diuretic, antispasmodic, purifying, estrogenic (moderate).
Uses: bloating and intestinal gas, water retention, detoxification support.
- Diluted abdominal massage for bloating
- Blend with citrus oils for draining support
- Avoid during pregnancy and in individuals with epilepsy
🌿 13. Ravintsara (Cinnamomum camphora CT cineole)
Respiratory tract · Cold season · Well-beingMain properties: highly valued in aromatherapy for its balsamic-fresh aroma and its traditional use to support respiratory well-being during cold periods.
Uses in aromatherapy: diffusion in autumn and winter, support for the upper respiratory tract, seasonal fatigue.
- Preventive diffusion in autumn/winter
- Diluted application on the chest and back
- Appreciated for seasonal well-being, also for children over 6 years old (with caution)
🌲 14. Atlas Cedar (Cedrus atlantica)
Grounding · Hair · ConcentrationMain properties: traditionally used for scalp care, to promote a sense of stability and grounding, and to accompany moments of dispersion or agitation.
Uses in aromatherapy: hair care, relaxing evening routines, moments requiring concentration and presence.
- Added to shampoo or pre-wash hair treatment
- Diffusion to create an atmosphere of stability and strength
- Blend with lavender and frankincense for deep meditation
🌼 15. Roman Chamomile (Chamaemelum nobile)
Calming · Sensitive Skin · ChildrenMain properties: anti-inflammatory, calming, antispasmodic, hypoallergenic, mild sedative.
Uses: irritability, agitation in children (over 3 years old, highly diluted), sensitive or reddened skin, menstrual pain.
- Evening diffusion to promote calmness in children
- Added to lotions and creams for sensitive skin
- Calming aromatic bath (a few drops in plant-based milk or bath salts)
| Essential Oil | Main Action | Preferred Use |
|---|---|---|
| Lavender | Relaxation, sleep | Diffusion, topical |
| Lemon | Energy, purification | Diffusion, home |
| Tea Tree | Hygiene, skin | Topical, diffusion |
| Peppermint | Concentration, digestion | Inhalation, diffusion |
| Rosemary | Memory, hair | Diffusion, topical |
| Eucalyptus | Respiratory tract | Fumigation, diffusion |
| Bergamot | Mood, anxiety | Diffusion, topical |
| Frankincense | Meditation, breath | Diffusion, inhalation |
| Vetiver | Grounding, insomnia | Diffusion (evening), topical |
| Geranium | Skin, feminine well-being | Diffusion, topical |
| Cardamom | Digestion, energy | Massage, diffusion |
| Fennel | Digestion, drainage | Topical massage |
| Ravintsara | Immunity, antiviral | Diffusion, chest topical |
| Cedarwood | Grounding, hair | Topical, diffusion |
| Roman Chamomile | Calming, sensitive skin | Diffusion, topical |
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How to use essential oils
The method of use makes a big difference in the effectiveness and safety of aromatherapy. Here are the four main methods, with practical guidelines for each.
1. Diffusion with an aromatic diffuser
Diffusion is the simplest, safest, and most universally accessible method. The most suitable method for those who want to fully appreciate the properties of essential oils is the dry diffuser: it nebulizes the pure oil directly into the air, without water or heat, preserving the aromatic composition intact. Alternatively, ultrasonic diffusers work with a mixture of water and oil and are a more delicate choice, mainly suitable for scenting rooms.
At EUODIA, we have four diffusers designed for different needs: AURA for compact spaces, ZENITH for those seeking design and performance in medium to large spaces, ZEFIRO for maximum versatility, and TAUER, our professional diffuser for rooms up to 60 m² and outdoor spaces. Choosing the right diffuser is the first step to getting the most out of your essential oils.
How to do it well:
- pour a few drops of pure oil directly into the diffuser compartment (follow the model's instructions)
- Diffuse for 30–60 minutes, then take a break for at least the same amount of time
- Vary the oils to avoid olfactory habituation
- Keep the diffuser clean (wash it with water and vinegar weekly) for water diffusers, use alcohol for dry diffusers
2. Massage with carrier oil
Topical application always requires dilution in a carrier oil: sweet almond oil, jojoba, fractionated coconut, argan, or sesame are among the most commonly used. The standard concentration for adults is 2–3%: approximately 12-18 drops of essential oil per 30 ml of carrier oil.
Where to apply:
- Wrists, temples (with extreme delicacy), and solar plexus for emotional effects
- Back, shoulders, and neck for muscle tension
- Abdomen for digestive support (circular movements clockwise)
- Soles of the feet (excellent skin absorption)
3. Aromatic bath
A warm bath enhances the absorption of essential oils both cutaneously and olfactorily. The oils should first be diluted in a dispersant (plant-based milk, honey, bath salts, or a tablespoon of almond oil) before adding them to the water.
- 8–10 drops in a full tub, diluted in the dispersant
- Water temperature not too high (40-41°C maximum)
- Soak for 15–20 minutes
- Ideal for evening: lavender, Roman chamomile, vetiver, ylang ylang
4. Direct inhalation
The most immediate and practical method. You can inhale the essential oil directly from the bottle (hold it 10 cm from your nose and inhale slowly for 3–4 breaths), or place a drop on a tissue or an aromatherapy personal inhaler stick.
For respiratory support, fumigation is very effective: pour 4–5 drops into a bowl of very hot water, lean your head over it, cover with a towel, and inhale for 5–8 minutes.
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How to choose a quality essential oil
The essential oil market is unfortunately full of products of questionable quality: oils diluted, adulterated with synthetic molecules, extracted with chemical solvents, or simply poorly stored. Knowing how to read a label is the first step towards a conscious purchase.
What to check on the label
- Botanical name in Latin: e.g., Lavandula angustifolia indicates the exact species. Without the Latin name, you have no guarantee of the plant used.
- Country of origin: geographical origin greatly influences chemical composition.
- Chemotyppe (CT): some plants produce oils with very different chemical compositions depending on growing conditions. E.g., rosemary CT cineole, CT camphor, or CT verbenone have distinct properties.
- Extraction method: steam distillation, cold pressing (citrus), CO2 extraction. Avoid oils extracted with chemical solvents for aromatherapy use.
- 100% purity: look for the explicit wording. Oils mixed with alcohol or vegetable oils must declare it.
- Dark packaging: true essential oils are stored in dark glass bottles (amber or cobalt) to protect them from light.
Certifications and traceability
Organic certifications (USDA Organic, ECOCERT, ICEA) guarantee that the plant is grown without pesticides. For wild plants, look for the wording "certified wild plant" or "wildcrafted". Supply chain traceability is the hallmark of a reliable producer.
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Common mistakes in using essential oils
Even with the best intentions, it's easy to make mistakes when starting with aromatherapy. Here are the most frequent ones, and how to avoid them.
- Applying pure oils to the skin. Essential oils are very concentrated: pure on the skin, they can cause irritation, burning, photosensitivity, and allergic reactions. Always dilute in a carrier oil.
- Diffusing for too many consecutive hours. Continuous diffusion for hours can cause headaches, fatigue, or nausea. 30–60 minutes is sufficient.
- Always using the same oil. Alternating oils is important to maintain olfactory sensitivity and to prevent the body from getting "used to" them, reducing perceived effectiveness.
- Buying oils of unknown quality. An adulterated or diluted oil is not only less effective: it can contain potentially irritating or allergenic substances.
- Using oils that are contraindicated during pregnancy, with children, or animals. Some molecules are contraindicated or require great caution in certain situations. Always inform yourself before using a new oil.
- Not storing them correctly. Light, heat, and oxygen degrade essential oils. Store them in a cool, dark place, tightly closed, away from stoves and windows.
- Expecting immediate results like those of a drug. Aromatherapy works subtly and gradually. Benefits are often perceived over time, with consistent and conscious use.
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Contraindications and precautions
Aromatherapy is generally safe if practiced knowledgeably. However, there are categories of people who must use essential oils with greater caution or avoid some altogether.
Pregnancy and breastfeeding
Many essential oils are not suitable during pregnancy, especially in the first trimester. Some can stimulate uterine contractions (sage, hyssop, fennel at high doses), others cross the placenta. During pregnancy, essential oils should only be used on the advice of a qualified aromatherapist or informed doctor.
Children
Children have thinner skin and a different metabolism than adults: some molecules (menthol, eucalyptol, camphor) can be dangerous under 6 years of age if inhaled in high concentrations or applied near the face. For young children, prefer low-concentration ambient diffusion and choose gentle oils such as lavender or Roman chamomile. For infants, always consult your pediatrician.
Pets
Cats, in particular, lack the liver enzymes to process certain phenolic and terpene compounds: oils like tea tree, eucalyptus, cinnamon, and peppermint can be toxic to them even at low concentrations. If you have pets at home, diffuse in well-ventilated areas and observe their reactions.
Sensitive skin and allergies
Before applying a diluted essential oil to large areas, always perform a patch test: apply a small amount to the inside of your wrist or elbow, wait 24 hours, and check for any redness or itching.
Medications and medical conditions
Some molecules present in essential oils can interact with medications (anticoagulants, antidepressants, thyroid medications). If you are on medication or have specific health conditions, talk to your doctor before incorporating essential oils into your routine.
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Discover EUODIA essential oils
Pure, traceable oils, carefully selected from trusted producers. Handcrafted diffusers and wellness kits for every need.
Explore the collectionFrequently asked questions about essential oils
What do essential oils do?
Essential oils are aromatic concentrates extracted from plants. Through olfaction, they can interact with the limbic system, the part of the brain that regulates emotions and memory. Depending on the oil and the context, they can promote states of relaxation, enhance concentration, or support daily well-being. They are not medicines; they are tools to support natural well-being, to be used consciously and consistently.
How are essential oils used?
There are four main methods: aromatic diffusion with a diffuser (preferably dry), topical application diluted in a vegetable carrier oil, direct inhalation or fumigation, and aromatic bath. The choice depends on the objective: a diffuser is ideal for mood and environment, topical application for muscles and skin, and fumigation for the respiratory tract.
Can essential oils be ingested?
Internal use of essential oils is not recommended without the supervision of a qualified medical aromatherapist. Essential oils are highly concentrated, and improper ingestion can cause irritation to the gastric mucosa, toxicity, or drug interactions. For daily well-being, diffusion or topical use is safer and equally effective.
Are essential oils safe?
Yes, if used correctly. The fundamental rules are: never apply them pure to the skin (dilute them in a carrier oil), use them with caution during pregnancy, with young children and pets, be mindful of photosensitizing oils before sun exposure, and always purchase certified quality oils. With these precautions, aromatherapy is an accessible and safe practice for most people.
How often can essential oils be used?
For aromatic diffusion, it is good practice to diffuse for 30–60 minutes and then take a break for the same duration, to avoid olfactory habituation. For topical use, the frequency depends on the oil and the purpose. In general, it is useful to vary the oils over time and not always use the same one for consecutive weeks, to maintain effectiveness and respect the sensitivity of the olfactory system.
What is the best essential oil to start with?
Three very versatile and accessible oils for beginners are: lavender (traditionally used for relaxation and evening routines), lemon (appreciated for morning energy and freshening up rooms), and tea tree (used for skin care and household hygiene). An excellent starting point for exploring aromatherapy.
What is the best diffuser for essential oils?
It depends on the space and how you intend to use it. Dry diffusers are the most suitable choice for those who want to fully enhance the aromatherapy properties: they nebulize pure oil without water or heat, preserving the aromatic composition intact. Ultrasonic diffusers are a gentler alternative, mainly suitable for scenting the environment. At EUODIA, we offer four dry models: AURA for small rooms, ZENITH and ZEFIRO for medium-large spaces, and TAUER for professional environments up to 60 m². You can also take our free quiz to find the diffuser that best suits you.
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Conclusion
Essential oils are an ancient heritage that contemporary research is increasingly valuing. They are not miraculous remedies, nor simple perfumes: they are tools for natural well-being that — used with awareness, quality, and consistency — can significantly accompany our daily lives.
If you are new to this, the advice is simple: start with three versatile oils. Lavender for relaxation and sleep. Lemon for morning energy and air purification. Tea tree for hygiene and skin care. With these three oils, you can already explore a large part of the benefits of aromatherapy, before gradually expanding your "aromatic palette."
The most important thing is to listen to your body and your responses to aromas. Olfaction is deeply personal: what is relaxing for one person can be stimulating for another. There is no single "right" oil — there is the one that is right for you, at that moment in your life.
At EUODIA, we work every day to help you find your personal aromatic path, with quality oils, carefully selected diffusion tools, and a wellness philosophy that centers authenticity and education. Welcome to the world of natural aromas.
Who wrote this article
Lorenza Poletto — founder of EUODIA
I founded EUODIA after more than twenty years in the IT sector, bringing with me an analytical attitude and the same attention to detail that has always guided my work. I embarked on an aromatherapy training path and work daily with essential oils, assisting clients who are new to this practice and enthusiasts who want to deepen their knowledge.
At EUODIA, I believe in aromatherapy disseminated with honesty: without excessive promises, with respect for the complexity of the topic, and with the clarity needed by those who want to make informed choices.
The information contained in this article is for informational purposes only and does not constitute medical advice, diagnosis, or therapeutic prescription. Essential oils are tools to support natural well-being and are in no way a substitute for consultation with a doctor or qualified healthcare professional. In case of illness, pregnancy, breastfeeding, allergies, or medication use, always consult a specialist before using essential oils.