“Essential oils that are used in aromatherapy are not always easy to find.” (“Aromatherapy: How Scents Can Heal Us — Grateful Earth”) The Food and Drug Administration does not regulate essential oils so you, the consumer, will have to carefully read the ingredients of any oil you purchase to make sure that it is in its purest form.
“To get the most benefit from aromatherapy, oils in their purest form should be used.” (“Aromatherapy: Essential Wisdom”)