Perfume Mythbusters: Hypo-Allergenicity of Natural Oils

As a scientist one of the more pervasive myths in perfumery is the one which says natural essential oils are hypo-allergenic. The myth goes that if it comes from nature instead of a chemistry lab it must be benign. It stems from this phobia many have about the word chemical. When I first moved to Boston I worked at a food co-op once a week. When I arrived for my shift one week there was a big display holding bags of decaffeinated coffee. On the sign above it was this, “We don’t use any chemicals to decaffeinate our coffee, only water.” I stood there laughing as I realized that right there in that simple statement was all that needs to be said about chemical versus natural. Water is a chemical made up of two atoms of hydrogen attached to one atom of oxygen. It is easy to understand that people associate the word chemical with dangerous and the word natural with safe. After all nature is safe, right? Just don’t attempt to clear out a bunch of poison ivy from your yard without the proper protection. Natural is not so nice if you get any of that on you. In fact if you do get some on you it is likely you will slather on a chemical mixture of zinc oxide and ferric oxide more commonly called Calamine Lotion.

The natural is good and the synthetic is bad paradigm exists in perfumery. There is the idea that a synthetic ingredient in a perfume has a greater ability to cause a skin reaction or a headache. The natural product is thought to be more pure with less chance to cause a physical effect. Just as with poison ivy and calamine the opposite is true. I am going to use Geranium Essential Oil versus the synthetic molecule Geraniol as my examples. The first thing you have to realize is Geranium Essential Oil is not just one single molecule it is literally dozens of molecules. In the graph below you see what is called a gas chromatograph trace of geranium essential oil. Each peak you see in the figure represents a molecule contained in Geranium Essential Oil. The bigger the peak the more there is of it. You see at the top of the figure that most of the major peaks have been identified as specific chemicals well-known in perfumery.

geranium essential oil gc

Graph from Sigma-Aldrich

As you can see below here is the gas chromatograph of synthetic Geraniol. One single pure peak and nothing else. In the previous graph is it is peak number 14.

Geraniol GC

Graph from Herbalanalysis.co.uk

Here is the fallacy in the natural is good synthetic is bad myth. If you find Geraniol is an ingredient which bothers you then that single ingredient is easy to avoid just by looking at the label. But if Geraniol bothers you and you take out an all-natural perfume of geranium containing Geranium Essential Oil you should have the same reaction. Now if you’re fine with Geraniol but not Linalool (peak 8 on the trace above) you can see the natural essential oil might present a problem for you. Especially if you are someone who prefers unscented bathing products as Linalool is one of the more common fragrance synthetics used in that sector. This is why an all-natural ingredient has way more things contained in it which might cause a bad reaction.

Before I finish this installment I also want to use these two gas chromatography traces to make another very important point. When the government agencies concerned with protecting the consumer from being exposed to potential allergens they cite single molecules as the cause. When they ban or restrict the use of a single molecule you think okay they’ll use an alternative. You’re right the perfumer who uses synthetics has much more latitude to find similar properties in another synthetic. What if let’s say Geraniol was to be banned. Would that mean that Geranium Essential Oil is also banned? It should be it has a high concentration of Geraniol. That is the possible very serious consequence to the use of natural oils if this governmental interference continues.

Finally I am thankfully free of any reaction to any perfume ingredient I have encountered. I can just judge a perfume on whether it does its job. Essential oils because of the wonderful complexity of their composition provide a richer experience than the simple single molecule ever could. If you want to know why natural perfumery continues to fascinate me so much it is because the talented perfumers working with an all-natural palette are using one-of-a-kind materials in fascinating perfumes. As for being hypo-allergenic that’s a myth.

Mark Behnke

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