AROMAPROFILES

Percutaneous Absorption

 Applying essential oils, in a base oil, directly onto the skin is central to aromatherapy and many trials have shown that essential oils, or components of them of them, show up in the blood or urine shortly after being applied through massage. Meanwhile, their absorption through the skin during baths is less of a mystery  since Dr Peter Slyko at the Kiev Institute of Physiology  (Ukrainian Academy Of Science) proved that for several minutes after sweating, the pores remain open and suck in whatever happens to be on the surface of the skin, which later shows up in the blood and the lymph.

Clearly the essential oils pass through the skin, the questions are how many of the components in essential oils pass through, and how do they do it? The first question is raised by the fact that the skin, the largest organ of the human body, is a site of metabolism - a place where chemicals in the body alter molecules, either to incorporate them into the body, to use them as fuel, or to expel them more easily.

Esterase enzymes, for example, are involved in these functions. The skin is also a place where one of the body's most efficient detoxification mechanisms are at work in the form of P450 enzymes.  These enzymes are found in high concentrations in the liver - the ultimate detoxification machine and, as we have seen, in the olfactory mucus.

As the purpose of the P450s is to prevent toxins damaging the body, this may help to explain the remarkably safe history of percutaneous essential oil use. It could be that the P450s either alter any harmful molecules or immobilize them, leaving them in the upper, dead layer of the skin, ready to be expelled.

The excellent skin permeability of the essential oils is usually attributed to their high lipophilicity. Once through the epidermal (outer) layer of the skin, the molecules are transported by the capillary blood and by interstitial fluid. Heat tends to falvour their absorption  - by having the room warm, the massaging hands warm, and by warming the oil in the hands before applying to the skin.

Absorption is also helped by covering the area of skin to which oil has just been applied, with a towel for example, thus preventing evaporation. The great advantage of percutaneous absorption is that essential oils can be applied directly to the area where they are required - to treat pain or inflammation, for example, and it is also an excellent way to get essential oils into the bloodstream and from there into all areas of the human being, including the brain.

Their Exit
Essential oils have different routes of exit, depending on their variety. It's thought that eucalyptus is exalted through breath, sandalwood leaves in the urine, patchouli in the feces and rose oil via perspiration through the whole skin. After a massage with 2 per cent lavender oil, the main constituents - linalol acetate - can be detected in the blood after just five minutes, with a maximum concentration after twenty minutes, while after ninety minutes most of the linalol and linalyl aceta have been eliminated from the blood.

This isn't to say that the effect of the lavender doesn't linger on - lavender and the other oils set off all kinds of chemical reactions in the body. The keys are turned in the locks, their jobs are done, and they can leave. It should also be said that while some of the more detectable components exit the body, the smaller compounds may be left behind in the body  for a longer time, to finish their jobs perhaps and, as we shall see later, there may be other factors at work.

Reference: The Fragrant Mind / Valerie Ann Worwood