Why Pharmacology Cannot Demonstrate Essential Oil Efficacy
To demonstrate the effect of a synthetic drug or a natural substance within the framework of pharmacology, two conditions need to be fulfilled. First there needs to be an experiment connecting a specific substance to a specific effect.
For example, to ascertain whether or not the molecule citral is a sedative, the duration of induced sleeping test animals is measured. In an ideal experiment, a specific amount of citral puts the test animal to sleep for a specific duration of time. If the dosage of citral is increased, the sleep duration would then be correspondingly longer.
Second, pharmacology expects to see the results of its experiments fit into a larger narrative, which describes a mechanism for the observed action. For instance, citral acts as a sedative, because it decreases the irritability of the central nervous system.
Ideally this contention is then demonstrated by another experiment, this time with a model on a lower level of organization, that is, not subjecting the whole animal t the test drug but showing the influence of citral on isolated nerve tissue.
The Reductionist Limitations
In a reductionist experiment only one of all possible variables is allowed to change. All others have to be kept at constant value. This standard reductionism process works relatively well for single component drugs, such as aspirin.
In the case of essential oils - where there is a potentially very large number of components contributing to the curative effect - this process is elusive, as the same experiment would when have to be repeated for each component of the essential oil.
While this might then be a proper reductionist procedure, it is neither practically possible nor would it describe a meaningful reality.
In order to make statements about multicomponent mixtures, pharmacology is forced to pick a (presumed) active ingredient and to measure its effect, if for no other reason than to keep the number of experiments manageable.
One has to conclude that the active ingredient concept does not arise from observing specific activity but is instead maintained so the reductionist process makes sense.
Using Lavender as a remedy for burns is again the classic example. It is highly effective, but only within the aromatherapy community. Pharmacology does not recommend the use of Lavender, since it cannot find an active ingredient that mimics the effect of the whole oil.
Plants in Art and Culture - Karl Blossfeldt
Reference: The Healing Intelligence Of Essential Oils: Kurt Schnaubelt, P h.D.