Inhalation, application and bathing are the three main methods used to encourage the entry of essential oils into the body. When inhaled, the extremely volatile oils may enter via the olfactory system, and permeation of the skin occurs when they are diluted and applied externally.
By bathing in essential oils, we can inhale and absorb the oils through the skin simultaneously.
Little is known about how essential oils actually affect the mind and the body, although research is ongoing in the USA, the UK and Australia. It appears that most essential oils are antiseptic and bactericidal to some degree, whilst some even seem to be effective in fighting viral infections.
On inhalation, essential oil molecules are received by receptor cells in the lining of the nose, which will transmit signals to the brain. Electrochemical messages received by olfactory centre in the brain then stimulate the release of powerful neurochemicals into the blood which will then be transported around the body. Molecules inhaled into the lungs may pass into the blood-stream and be disseminated in the same way.
When rubbed or massaged onto the skin, essential oils will permeate the pores and hair follicles. From here, they can readily pass into the tiny blood vessels (known as capillaries) by virtue of their molecular structure, and then travel around the body.
Once absorbed, the action of the oil depends upon its chemical constituents. Most essential oils are high in alcohols and esters, although a few contain a high concentration of phenols, aldehydes and ketones. The latter are powerful chemicals and their use should be avoided by all save the skilled professional.