Methods: Inhalation and Topical Application of Essential Oils
By
Shellie Enteen,
RA, BA, LMBT
March 24, 2011
Methods: Inhalation and Topical Application of Essential Oils
By
Shellie Enteen,
RA, BA, LMBT
March 24, 2011
It's my hope that the information and guidelines presented in this and following articles on the basics of aromatherapy, culled from more than 20 years of experience, will help propel Massage Today readers in the right direction on a journey through the wonderful, welcoming and profitable world of essential oils.
When working with essential oils in massage, it is helpful to understand the way they enter the body. There are two basic pathways that we utilize in a massage practice: inhalation and topical application.
Inhalation and the process of olfaction are well documented and understood. During inhalation, the volatile molecules of essential oils become a vapor which contacts the sensory nerves in the nasal passage. Now, the vapor is converted to an electrical charge that is carried via the olfactory nerve to the olfactory bulb and into the brain. (At this point, there are several theories of how the charge is recognized.) However, it is then conveyed to the limbic region and reaches the hypothalamus, where it will continue on to either the ANS or the pituitary gland to stimulate hormone activity. Other molecules will pass into the cerebral cortex, stimulating memory, learning and emotional responses. Blood circulation is immediately accessed during inhalation via the nasal mucosa and the alveoli in the lungs.
Inhalation of essential oils is achieved through diffusion via machine or air sprays in the office or treatment room. It is also the most direct pathway of the aromatic blend or essence used during the massage. The therapist and other clients or office staff will also receive essences diffused into common areas via inhalation. Because of this, it's good to note that regarding true essential oils (versus synthetic fragrance), once the brain recognizes and transmits the information of the essential oil molecule, the sense of smell is satisfied and the fragrance may stop being detected -- unless we leave the room and re-enter, causing this to become "new information" for the olfactory nerve to deliver. However, the molecules remain active and in the air for hours.
Unless an air purifier is used between clients, the treatment room can become a muddled mixture of blends. This will tamper with the purity of the specific aromatic treatment. For example, if the goal is to relax a client, but stimulating essences are still in the room, the relaxing effect will be lessened ... and vice versa. The buildup can also become overpowering for the therapist. For these reasons, using an air purifier to clear the aromatic molecules in the room while the sheets are being changed is a very good idea. And because the constant diffusion of essential oils will also build up in the waiting room, a time release diffuser is preferable. It is best to use essences that are neither too sedative or stimulating, such as those from citrus and wood, for common areas. For greatest purity of experience, use no fragrance at all in the rest of the office or in the treatment room.
Unlike inhalation, the amount and action of essential oils absorbed in topical application is not as well understood, nor can it be completely and accurately described at this time.
Dermal penetration presents a more difficult route, beginning with the fact that percutaneous absorption requires that the essential oil in liquid form enters the stratum corneum, the thin outer layer of the skin that is equipped to protect the body from invading organisms. Hair follicles, eccrine and apocrine glands, which account for only 1 percent of the skin's surface, provide easier access than the cells and keratin content of the stratum corneum. Thus, certain areas of the body are said to be more permeable: forehead and scalp, soles and palms, genitals, armpits and mucous membranes.
According to aromatherapist and educator, Salvatore Battaglia, if the essence is able to permeate the complex biological functions of the stratum corneum, a variety of things can occur. One potential is for the essential oil molecule to remain in the skin itself, where it may be metabolized by cutaneous enzymes. (It is speculated that enzymes may convert some components, such as safrole, methyl chavicol and carvacrol, into potentially harmful substances.)
Another possibility is that the essence remains in the skin, forming a reservoir by binding to the stratum corneum or subcutaneous fat where it may be slowly released into the capillaries. The best case scenario is that all or part of the essential oil components will reach and be completely absorbed into the cutaneous micro-circulation.
Essential oil components may also bind with proteins in the skin, which creates the sensitizing response of allergic contact dermatitis. Skin permeability may be increased by:
- Alteration of the stratum corneum due to cuts, abrasions or thinning of this layer.
- Hydrating the skin through bath, sweating, being in a highly humid environment, such as a steam room or steam cabinet. Using an aromatherapy massage oil after a hot bath or shower may increase the absorption of essential oils because of stimulated blood flow to the dermis.
- Using a carrier oil that is more easily absorbed (such as fractionated coconut) as opposed to thicker oils, like olive, that will be absorbed more slowly. Oils rich in polyunsaturated fats are absorbed more easily and certain fatty acids found in cold-pressed vegetable oils also enhance penetration.
- The use of soap or other surfactants increases permeability. Combine that with the hot shower or bath and an aromatherapy shampoo/shower gel would get a high topical rating.
- Covering the skin to inhibit evaporation and raise the temperature of the skin (via massage linens, clothing, wraps, masks and other products), which also increases hydration of the skin, circulation to the skin which assists permeability.
Research about skin absorption rates have not resulted in a clinically proven pathway to date. In addition, none of these studies or speculations takes into account the vibratory action of the essence when it touches the body. These effects can be experienced, even if not successfully measured.
Regarding the topical method, Sylla Sheppard-Hanger writes, "Just because whole essential oils may not be absorbed into the bloodstream creating a systemic reaction, beneficial skin affects and certainly the mental effects (relaxation) are very much possible with essential oil treatments. ...Certainly the beneficial mental effects induced when using a pleasing fragrance cannot be denied."
The combination of inhalation, vibration and potential dermal penetration, coupled with the caring touch of the therapist could well be the reason Sylla concludes, "The safest and most pleasant method of delivery is the external use of essential oils (highly diluted), usually in the form of massage."