How Essential Oils Enter the Body
There are three paths that essential oils can enter into the body:
- absorption through the surface of the skin
- inhalation through the olfactory system
- taken internally
The optimum way for the body to absorb the therapeutic qualities of essential oils is through a combination of inhalation and dermal absorption which can be achieved through massage and bathing.
When essential oils are inhaled, the molecules rise to the top of the nose and meet the olfactory mucous membrane. The olfactory membrane has thousands of receptors that identify the smell and thus, the sensory stimulation is sent through the olfactory bulb, which acts as an amplifier, through the olfactory nerve into the limbic system of the brain. This is the oldest area of the brain. It deals with emotional and psychological responses. The limbic system is triggered by nerve impulses. The scent is compared to a known scent, compared and labeled, thus we can have memories associated with the scent information and react emotionally and physically through our autonomic nervous system. These responses are determined by the specific qualities of the essential oil being used, and can range from relaxing to stimulating. The nerve impulse in the limbic system leads to other areas of the brain that are responsible for secreting hormones and regulating body functions. The entire process from the initial inhalation of the oil to corresponding gland secretion takes place in a matter of seconds. Therefore, a simple inhalation can cause changes in the body from stimulating the immune system, to initiating the digestive system into action and so on.
The skin is relatively permeable to fat soluble substances and relatively impermeable to water soluble substances. Essential oil molecules are so minute that when they are applied to the skin; they are able to pass through the strateum corneum (the outer layer of the epidermis). From here the oil molecule passes through dermis, into the capillaries and into the bloodstream. Absorption also occurs through the hair follicles and sweat ducts. There are many factors that effect absorption of an oil molecule. Both rate of circulation and the warmth of the skin increase blood flow to the surface, therefore increasing the skin’s ability to absorb the oil. Circulation and warmth can be increased by massage. The larger the area of skin that is covered, the more essential oils will be absorbed. The permeability of the skin is also a factor. Thinner skin ie: skin behind the ears and the inside of the wrists are very permeable. The palms of the hands and feet, armpits and scalp will more readily absorb oil molecules than the arms, legs, belly, back etc. Oils are also easily absorbed through cuts, scraps and abrasions, burns, excema etc.
Having clean skin is also beneficial as the skins pores will be clean and free of dirt, which may impede absoption.
The other factor to consider when applying essential oils to the skin is the viscosity of the carrier oil in which the oil is diluted. Sweet Almond and Grapeseed Oil are less viscous and will penetrate the skin more easily than Olive or Avocado oils, which are thicker.
Studies show that taking essential oils internally is the least effective way to absorb their therapeutic properties. The oil ends up in the digestive tract where it has to pass through the stomach and small intestine before it reaches the bloodsteam. From there the oil molecules which, by now have been chemically altered by the materials they have come into contact with in the stomach and intestine; will reach the liver, pancreas, reproductive organs and eventually be excreted via the kidneys, bladder and large intestine. It is not advised to ever take essential oils internally unless under the direct advise of a medical doctor who is also a Registered Aromatherapist.