Hydrolats, and Their Benefits In Aromatic and Topical Aromatherapy

Aromatherapy is a natural therapeutic healing modality using aromatic substances to achieve physical, emotional, spiritual and energetic healing. Robert Tisserand has defined aromatherapy as follows: “Aromatherapy is a caring, hands-on therapy which seeks to induce relaxation, to increase energy, to reduce the effects of stress and to restore lost balance to mind, body and soul” (Tisserand, 1988, p.1).

Essential oils are the most commonly used products in aromatherapy. Hydrolats (also known as hydrosols) are beginning to play an increasingly important role in modern-day aromatherapy. These effective and fragrant waters are often thought of as a bi-product in the distillation process of essential oils. Hydrolats are more than a bi-product and are, in fact, a co-product of distillation (Malle and Schmickl, 2015). They contain natural chemical constituents (some of which cannot be found in essential oils) with aromatic and topical benefits and are highly useful in the field of aromatherapy.

Hydrolats are aqueous solutions created through the process of steam distillation of plant material. The plant material used to create a hydrolat may include flowers, stems, leaves, seeds, bark, resin, grass, roots and more. Hydroolats (known today as “Hydrolats”) were first defined in 1825 by Pharmacist Antoine Chereau as: “Medicinal waters that are obtained by distillation...A hydroolat is an ordinary distilled water” (Lewis, Hydrolats in Clinical Care. Aroma Summit, 2023). The term “Hydrolats” was refined by Guerain (1886), as a pharmaceutical term: “ A colourless liquid which is obtained by distilling water with odorus flowers or with some other aromatic substances” (Price and Price, 2004, p. 33).

Non-aromatic plant materials do not contain essential oils, however, when they are distilled, many of them do contain beneficial molecules in the hydrolat. “They are produced when distilling either aromatic or non-aromatic plant material” (Harman, 2023, p. 23).

Though the name “Hydrolat” was defined in the late 1800s, people have been using hydrolats in unrefined forms for thousands of years. It has been discovered that for at least 5000 years, plant and fragrant waters have been used medicinally (topically and internally), spiritually and as perfume (Bosson, 2019). Historically these materials were extracted in less sophisticated ways as they did not have modern equipment or technology. Hydrolats predate the discovery of essential oils which can only be dated back to the 10th century (Forbes, 1970). “In the beginning, up until the early Middle Ages, the process of distillation was used almost exclusively for obtaining distilled plant waters; even after this time, it was the chief aim of distillation for several centuries” (Price and Price, 2004, p.11).

In the late 1300s, Catalan Physician, Arnald de Villanova discovered advanced distillation processes which shifted the focus of distillation from hydrolats toward essential oil production (Price and Price, 2004). With the rise in popularity of essential oils, synthetic fragrances and pharmaceuticals, the use of pure hydrolats greatly diminished. “Production and use of distilled plant waters reached its height during the 18th century”. (Price and Price, 2004, p.16). As a result, hydrolats have been considered a bi-product in the creation of essential oils, losing their momentum in the healing world.

In addition to the growth of the essential oil industry, synthetic floral waters became far more accessible and less expensive. Artificial essences and fragrances do not contain bioavailable chemical constituents of pure hydrolats and essential oils making them ineffective for aromatherapy. “Synthetic copies do not, however, seem to have the same respect for living human tissues and tend to be more toxic” (Price and Price, 2004, p. 16). There are other factors influencing the decline of hydrolats. They are not easy to store, ship, package or distribute. There is also very little public understanding about hydrolats and it can be difficult to find published chemical profiles. “Consequently, the demand for these valuable products of the distillation process is not very high. This, in turn, means that suppliers have felt they can only keep low stocks of a small range of waters” (Price and Price, 2004, p.3). They are heavy, bulky and often have a shorter shelf-life than their co-product, the essential oil. The water used in the process is critical as it must be pure and the plant material must be organic and free of pesticides or other chemical residue. “When distilling for hydrosols, the water used in the production is of great importance, as it will become part of the final product” (Harman, 2023, p.26). This has made it a less desirable product for the industry to market as it would be a far more expensive and tedious venture to undertake, therefore over time hydrolats have been overlooked, under-appreciated and discarded.

Synthetic beauty and healthcare products such as fragrances, skincare and pharmaceuticals are still very common, however with access to more information, scientific-based evidence, and a growing awareness of the potential side effects of short and long-term use of synthetic products, more people are beginning to seek natural alternatives. Because of this shift, the use of hydrolats is once again gaining in popularity and becoming more available (Price and Price, 2004).

Due to advancements in technology, continued research, countless case studies and the ability to analyze hydrolats on a microscopic level, more evidence of their therapeutic properties is being proven. “Hydrosols are quickly becoming much beloved for their gentle yet exceptional benefits for the skin and on emotional well-being...There’s never been a better time to explore these remarkable waters” (Shutes and Galper, 2020, p. 155). The use of hydrolats as natural, gentle remedies for a wide range of concerns including skincare and emotional wellness for people of all ages are just a few of the many ways to use these waters.

“Anyone who has worked with the therapeutic waters would agree that they are a multi-layered healing modality” (Harman, 2023, p.23).

The creation of a hydrolat is both a science and an art. In order to yield the highest quality hydrolat, each step in the distillation process is of utmost importance. The distillers are tasked to ensure the highest quality, fresh, organic plant materials are used, harvested at an optimal time and with knowledge of the specific biological species of plant used. They must be distilled using pure spring or distilled water. Each consideration will result in a variance in the final product of the distillation (Price and Price, 2004).

Hydrosols appear to look like plain water however they contain water-soluble nutrients, plant acids, as well as aromatic molecules with healing properties (Mauray, 2020). “Hydrolats are used most particularly in European phytotherapy, a form of herbal medicine...In some way, the aromatic molecule, or vibration of the essential oil, has managed to become imprinted in the water” (Worwood, 1994, p.28).

The chemical properties found in hydrolats are an important factor in their use in aromatherapy. When the steam passes through the plant matter during steam distillation, there are volatile organic compounds (VOCs) from the plant which are separated and captured in the steam. It is then condensed and cooled and a collection of essential oil and hydrolat is created (Tisserand and Young, 2014). VOCs contain hydrophilic and hydrophobic molecules. Hydrophilic molecules are considered water-soluble and hydrophobic molecules are not soluble in water. Hydrophilic molecules will mostly be found in hydrolats and hydrophobic molecules will separate and are predominantly found in the essential oil (Price and Price, 2004).

Determining the molecular composition of a hydrolat is done through scientific analysis. A sample of the hydrolat is taken, concentrated, extracted and analyzed by gas chromatography-mass spectrometry (GC-MS). The GC-MS will give a detailed breakdown of the molecular components found in the sample (Price and Price, 2004). Essential oils and hydrolats may contain the same, similar or very different molecules.

“The hydrolat and essential oil composition from the same plant can be very similar or very different. It’s all down to chemistry. Volatile plant acids being the most polar, are rarely found in essential oils but are found in hydrolat. Hydrocarbons being the least polar are rarely found in hydrolats unless in microdispersion” (Rhiannon Lewis, Aroma Summit, Hydrolats in Clinical Care, 2023).

The GC-MS report for each hydrolat is an essential tool for determining the properties of the hydrolat and its potential therapeutic benefits.

“Hydrosol therapy is part of herbal medicine and aromatherapy. The active ingredients in hydrosols are not identical to those of essential oils, as certain components in plants are hydrophilic, which means that they dissolve in water. As such, these elements are preserved in hydrosols but not in essential oils. Hydrosols contain more organic acids, often considered to be anti-inflammatory, as well as other soluble herbal substances” (Bosson, 2019, p. 21).

How the human body is affected physically, emotionally and spiritually by hydrolats may be attributed to the biological reaction from the chemical constituents in the hydrolat. This can include negative effects due to the toxicity of a given compound if the concentration is too high. “Certain molecules are very well tolerated (linalool) with more or less no side-effects, while others like ketones or phenols can be dangerous” (Bosson, 2019, p.18).

Some of the specific molecules with therapeutic properties which have been found in hydrolats through GC-MS analysis are alcohols, esters, acetates, hydrocarbons, ketones, coumarins, oxides, sulphides and aldehydes (Price and Price, 2004).

The practical use of hydrolats requires analysis and interpretation of the GC-MS reports as well as research of individual case studies. The constituents identified in GC-MS reports taken from a wide range of hydrolats have been found to have the following properties; Alcohols can be toning, stimulating, sedative and balancing. Ethanol is an anesthetic, pruritic, antiseptic, astringent, CNS-depressant, hemostatic, rubefacient and used as a skin disinfectant and ulcerogenic. Geraniol is known for its sweet floral scent and is said to be an anticarcinogenic, antiseptic, antitumor, bactericide, fungicide, sedative and spasmolytic. Linalool can be antiallergic, anticarcinogenic, antihistamine, antiseptic, antiviral, bactericide, broncho-relaxant, expectorant, fungicide and spasmolytic. α- Terpineol is mostly used in perfumes and as an antiseptic. Esters including linalyl acetate are often used in perfumes and are sedative and spasmolytic. Bornyl acetate has bactericide, expectorant, sedative, spasmolytic and antiviral properties. Properties of hydrocarbons such as pinene are found to be antiseptic, bactericide, expectorant, fungicide, spasmogenic and spasmolytic. α- Pinene has properties including, anti-inflammatory, antiviral, bactericide, expectorant, irritant and sedative. β-Pinene and Sabinene are used in perfumery. Caryophyllene has anticarcinogenic, anti-inflammatory, antitumor, bactericide and spasmolytic properties. Aldehydes and hydrocarbons are known for their calming properties. Ketones such as acetone contain allergenic and CNS-depressant properties. This can cause irritation to nails, skin and lungs and is found in many distilled waters but typically at low enough concentrations to not cause any problems. Camphor is cooling to the skin, antiseptic, anesthetic and readily absorbed through the skin, allergenic, antiacne, antiseptic, CNS-stimulant, carminative, counterirritant, decongestant, expectorant, fungicide, rubefacient, spasmolytic and stimulating. Carvone is antiseptic, CNS-stimulant, carminative, sedative and stimulant. Thujone can have paralyzing effects and can be anthelmintic, bactericide, convulsant, counterirritant, hallucinogenic, spasmolytic and toxic. Oxides such as Eucalyptol (1,8-cineole) are widely used in pharmaceuticals and have the following properties: expectorant, stimulant, anesthetic, antiseptic, anti-inflammatory, anthelmintic, antiallergic, anti-bronchitic, anti-catarrhal, antitussive, bactericide, CNS-stimulant, expectorant, fungicide, rubefacient and sedative. Sulphides, specifically dimethyl sulphide found in hydrolats can help break down ketones, reducing their toxicity (Price and Price, 2004).

The skin and olfactory system absorb the molecules from hydrolats very well which is why they have many beneficial topical and aromatic uses. It is clear, from a molecular level, that their therapeutic actions are extensive. “The active ingredients of naturally pure essential oils or hydrosols are absorbed by the skin and spread by the circulatory system” (Malle and Schmickl, 2015, p.8). In order to effectively use hydrolats, it is important to review the GC-MS reports for each type and have an understanding of the biological effects based on their chemical constituents and respective properties.

Thanks to the chemical constituents found in hydrolats, they have a multitude of topical uses in beauty, skincare and hygiene. “Hydrosols are quite versatile in their use. Their pH of 5-6 makes them particularly appropriate for toning skin, for well-being, for baby care, for use in food recipes and simply for the pleasure of the senses that their use provides” ( Bosson, 2019, p. 22). They are diluted enough for use in sprays and to splash directly on the skin (Keville, 2016). They can be applied by ways of spritzing, soaking (full body, sitz bath or foot bath), massaging, gargling, facial steam, using as a nasal spray, enema, in eye care, adding to a hot compress, or adding to skincare products such as creams, lotions and masks (Bosson, 2019).

“They have subtle effects without the risk of irritation and are suitable for sensitive skin, babies, children, and even eye care as their action is mild compared to that of the essential oils, and because of their non-aggressive quality they can be used on open wounds for disinfection and on mucous surfaces” (Price and Price p. 32).

Contraindications using hydrolats are minimal as many of the volatile components most often found in essential oils are not found in the waters. If they are present, they are at a very low concentration. “Distilled plant waters may have, in certain cases, generally similar properties to the parent oils depending upon their composition, but not of course to the same degree, and can be used as gentle therapeutic agents” (Price and Price, 2004, p.33).

In skincare, hydrolats can be used for enhancing beauty by toning, cleaning, hydrating, lifting blackheads, reducing swelling and scars and balancing oil production (Rose, 1999). “They’re also great for refreshing toners or body splashes because the fragrance is much more delicate than those of herbal extracts or essential oils” (Schuhmann, 2021, p.79). They can be used to reduce itch, rashes (including diaper rash), dermatitis, wounds, sweating, intertrigo, impetigo, hemorrhoids, intimate hygiene, shingles, herpes, pain, hyperalgesia, sore nipples for breastfeeding mothers, and malodour management (Lewis, Hydrolats in Clinical Care. Aroma Summit, 2023). They have wonderful antibacterial, antiseptic, anti-inflammatory, and astringent qualities and are most often safe for use with babies. “Roman Chamomile sprayed on the gums calms teething pain” (Bosson, 2019, p.29).

“Hydrosols can soothe irritation, clean away bacteria and microbes from a cut or injury, reduce inflammation, support wound healing, soothe a sunburn, soothe irritated skin, and be used in gels for the skin, muscular aches and pains or varicose veins. Hydrosols can be used in baths, aromatic spritzers, homemade creams and lotions, and cleansers. They can also be used as toners for gentle skin care” (Shutes and Galper, 2020, p. 156).

Aromatically, through deep inhalation, hydrolats can be beneficial for internal, mental, emotional, energetic, holistic and spiritual wellness. “Essential oils and hydrosols develop their fragrances especially well in warm water and are absorbed both through the olfactory nerves and through the skin” (Malle and Schmickl, 2015, p.7). Various properties in hydrolats can help to ease stress, depression, anxiety, insomnia, mental and physical fatigue, drug withdrawal, nervousness, mental strain, hormonal imbalances, jet lag and hot flashes. Hydrolats also help to increase circulation, alertness and soothe the heart. They can be euphoric, uplifting, calming, energizing, relaxing, comforting, revitalizing, refreshing, detoxifying, sedative and used as aphrodisiacs. These waters can also be used for spirituality, spiritual healing and in meditation practices (Rose, 1999). This therapy can be achieved by using hydrolats as room sprays to purify the air, spraying sheets and linens, diffusing, spritzing the face and body or adding to a bath. “Energy hydrosol therapy, subtle waters, or hydrosols are imbued with the soul of the plant. They often act rapidly on psycho-emotional and spiritual levels” (Bosson, 2019, p. 24). Inhalation of hydrolats, as with essential oils, can help to ease other conditions such as rhinitis, bronchitis, sinus infections, congestion and migraines (Bosson, 2019).

These incredibly gentle and effective waters have a long history of topical and aromatic uses for emotional, mental, physical and spiritual wellness. With modern technology and GC-MS reports, we are in a better position than ever to understand the benefits and uses of hydrolats in topical and aromatic aromatherapy. Hydrolats expand the tools available to aromatherapists for treating their patients and give a safe alternative to, and can be used in conjunction with, their co-product, essential oils.

Written by: Sarah Vezer

Works Cited

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