Aromatherapy - Choice and Purchase

Choice and Purchase

Oils with standardized content of components (marked FCC, for Food Chemical Codex) are required to contain a specified amount of certain aroma chemicals that normally occur in the oil. But there is no law that the chemicals cannot be added in synthetic form in order to meet the criteria established by the FCC for that oil. For instance, lemongrass essential oil must contain 75% aldehyde to meet the FCC profile for that oil, but that aldehyde can come from a chemical refinery instead of from lemongrass. To say that FCC oils are "food grade", then, makes them seem natural when, in fact, they are not necessarily so.

Undiluted essential oils suitable for aromatherapy are termed therapeutic grade, but there are no established and agreed standards for this supposed category. The market for essential oils is dominated by the food, perfume, cosmetics and pharmaceutical industries, so aromatherapists have little choice but to buy the best of whatever oils are available.

Analysis using gas liquid chromatography (GLC) and mass spectrometry (MS) is used to establish the quality of essential oils. These techniques are able to measure the levels of components to a few parts per billion. This does not make it possible to determine whether each component is natural or whether a poor oil has been 'improved' by the addition of synthetic aromachemicals, but the latter is often signalled by the minor impurities present. For example, linalool made in plants will be accompanied by a small amount of hydro-linalool, whilst synthetic linalool is contaminated with traces of dihydro-linalool.