ISO QUALITY
The ISO created quality standards for essential oils under the TC-54 Guidelines. One of these quality guidelines is to use Gas Chromatography to test for the active phytochemical content of each oil and if it does not meet these minimum amounts, the oil is not considered of value. Most essential oils companies do not even consult these guidelines when purchasing their oils, thus they cannot be of any theraputic value even though they may use that term as a marketing strategy. If an oil is not ISO certified, then do not buy it.