In aromatherapy, there’s a concept known as “quenching.”
For example, take citral, a compound found in lemongrass oil.
Normally, if citral is applied to the skin without being diluted enough, it will cause skin sensitization.
However, if citral is combined with limonene (also present in lemongrass), it doesn’t seem to sensitize skin as much.
This is quenching — a positive synergy between essential oil constituents that seems to take away some harmful effects.
Quenching can happen between the constituents of a single essential oil (like lemongrass), or between the constituents of different oils in a blend (say, spearmint and lavender).
What about the other direction?
While I haven’t heard anybody give a name to it, the opposite phenomenon also appears to exist. Let’s call this essential oil “stoking.”
For example, a team of scientsits just studied the toxic effects of the compound thujone in various neurotoxic oils such as a Dalmatian sage and wormwood.
Thujone is a well-known neurotoxin itself, and the scientists tried to analyze how much of the toxic effect of the whole oil is due to this one compound.
The answer was “some, but not all.”
In other words, the whole oil contributed to the toxic effect, even when accounting for the single harmful compound.
If I’m starting to lose you with all of this abstract talk, here’s what I’m getting at.
It’s really hard to predict how the individual components of essential oils interact with each other, and then with your body.
It gets ever harder when you blend essential oils together and double or triple the number of components and their interactions.
So how can you figure out what’s safe and what’s not?
Tradition can give you a start. By “tradition,” I mean expert aromatherapists who have worked with hundreds or thousands of clients.
Science can also help, like in the study above.
But ultimately, your own careful and gradual personal experimentation is the final verdict.
It comes back to the point that you have to get educated about essential oils, and then you have to try things for yourself.
By the way, if you want to read the full article about essential oil stoking, here’s the link to the dry, crackling scientific text: