Aroma Chemicals vs. Essential oils…What’s the big deal?

Updated: Jul 11, 2018

First of: I am not a chemist. Just a reader. So feel free to contact me regarding any correction of anything that I might have misunderstood, or just to let me know what you think. Ok? Let’s start:

Out there you will find A LOT of people stating things like "I don’t put anything in my perfumes or in my products that is not natural” or “We prefer to avoid chemicals since they are potentially hazardous to human health"

Let's make something VERY  clear from the beginning, so you can stop right on their tracks anybody that comes with an argument like that:


We live in a chemical world and WE ARE chemistry! The air we breathe is a mix of different chemicals elements, our bodies create and transform chemical components, we eliminate chemical components, even the water we drink (H2O), Hydrogen and Oxygen, is a chemical. So making a product without chemicals is not only a lie but a fallacy and an impossibility.

What is the problem with using chemicals, then?

Well, the answer is quite simple: NONE. If there is someone or something to blame for chemical hatred, that would be IGNORANCE and MARKETING.

But before getting into that, let’s understand some terms, so we can form an educated opinion about what we are about to discuss:


Essential oils come from different plant materials and they are "essential" in the sense that they contain the "essence of" the plant's fragrance. They are obtained, depending on the plant material, through different processes:

  • Enfleurage: One of the oldest methods. High cost. It basically involves placing flower petals on a layer of glass that is first spread with a thin layer of fat called "chassis". The volatile oil is transferred then from the petals into the fat, then the fat is collected and the oil is extracted from the fat using alcohol. Once the alcohol evaporates what is left behind is called an “absolute”.

  • Expressed Oils: Oils are taken from the rind of fruits. This method is cold and does not involve any solvents or heat. Basically, by pressing the rind of the fruits, tiny “sacs” containing the oil are ruptured and release the oil. Most of the citrus oils are extracted in this manner including grapefruit, lime, orange and lemon essential oils.

  • Steam Distillation: The most common process, involves the flow of steam into a chamber holding the raw plant material. The steam causes the small sacs of the plant material containing essential oil to burst. The oil is then carried by the steam out of the chamber and into a chilled condenser, where the steam once again becomes water. (Hydro-distillation is a similar process where the plant material is boiled, with the resultant steam being captured and condensed). The essential oil is then separated from the water, which is also referred to as a ‘hydrosol’, or flower or floral water and is commercialized as well since it has some of the plant essence.

  • Solvent Extraction: Here the plant material is immersed into a solvent (hexane, acetone, di-methylene-chloride, etc.) forming a thick substance called "concrete". This concrete contains essential oil, waxes and resins. Then ethyl alcohol is used to extract the fragrant oil from the concrete. The alcohol solution is chilled down to −18 °C (0 °F) for a couple of days which causes the waxes and lipids to precipitate out. The precipitates are then filtered out and the ethanol is removed by evaporation, leaving behind anabsolute (incredibly strong and complex aromas).

  • CO2 and SCO2 - Carbon Dioxide and Supercritical Carbon Dioxide Extraction: Fairly new solvent extraction processes that use carbon dioxide as a solvent at very high pressure. The carbon dioxide is injected into a tank which carries the essential oil away from the raw plant material.

  1. CO2 extraction: (lower pressure) involves chilling carbon dioxide to between 35 and 55 degrees F and pumping it through the plant material at about 1000 psi (pounds per square inch). The carbon dioxide in this condition is condensed to a liquid.

  2. SCO2 extraction: involves carbon dioxide heated to 87 degrees F and pumped through the plant material at around 8,000 psi – under these conditions, the carbon dioxide looks like a ‘dense fog’ or vapor.

By releasing the pressure in either process, the carbon dioxide escapes in its gaseous form, leaving the essential oil behind.

So up to here we just got the HOW. How natural essential oils are obtained from the natural raw plant material. But let’s talk about the WHAT.

What’s inside the natural essential oil, what is it composed of?

Essential oils are complex mixtures, constituted by terpenoid hydrocarbons, oxygenated terpenes, and sesquiterpenes. All of these, yeah I can see the look in your faces, belong to the realm of CHEMICALS! Yeah! (Remember? EVERYTHING IS CHEMICAL!). 

Let’s take a look at the following table that shows us the chemical composition o

different spices and herbs essential oils.

We can see that each essential oil in there has more than 35 constituents or compounds in it (and those are just some of them, usually there are more than a hundred). And the names! OMG, did you see those weird names? α-terpinyl acetate?, β-caryophyllene?, dihydrocarveol?

One thing is saying natural thyme essential oil but when you say a combination of α –thujene, 1,8-cineole, cis-sabinene-hydrate and other 32 chemical components all of a sudden it doesn’t sound THAT safe or natural, right? Yet….for our nature advocates…it’s all natural…it’s all good (I can almost see them sitting there, all mighty high, smoking natural weed, looking down at us, aroma chemical users, despicable sinners…lol).

Using the information of the table we could say that the principal components of sage essential oil (Salvia officinalis) are camphor (24.95%), 1,8-cineole (24.75%) and camphene (7.63%) or that the predominant compounds in clove essential oil (Syzygium aromaticum L) are eugenol (85.5%), β-caryophyllene (10.54%) and α-humulene (3.12%). Here it is important to understand that having a high percentage doesn’t necessary mean that is the main odor. Sometimes, as little as less than 1% of a constituent can bring the characteristic odor of an essential oil.

So far so good. This is key to understand the comparison betweennatural essential oils and aroma chemicals.

Now, the problem is that there are a lot, I mean A LOT of natural constituents of essential oils (yes, the ones that come from nature and everybody thinks are pure, healthy, safe and innocuous…) that are potentially hazardous to human health.


What do you mean? You are mistaken…!

I mean that they are proven to be carcinogenic, sensitizers, toxic, irritants, phototoxic, neurotoxic, etc.


OMG! Are we talking about NATURAL ESSENTIAL OILS HERE? Are you sure they are NATURAL? You HAVE to be wrong. All these years having the wrong beliefs? I’m about to have a panic attack. Oh my God!, where’s my KABA KABA?????!!!!!!

I know, I know, but don’t panic. Luckily there is an institution named IFRA that, based on constant studies of chemical constituents and its interactions with us, human beings, suggest which are the constituents of a natural essential oil that we shouldn’t be using at all (banned) or we should use just a tiny bit –a percentage– (restricted).

As instance, bergamot essential oil has a constituent called bergapten which is known to be phototoxic. This means that if for example, you put some bergamot essential oil on your arm (which you shouldn’t, this is just an example) and then you expose your arm to the sun, you will most likely get a bad reaction on your skin. Because of this, there is a restriction set out by IFRA on the amount of bergamot essential oil we can use in, let’s say, a perfume, lotion, soap, etc. Clear? Great. Let’s continue.

So now the term “natural” doesn’t seem to be so natural whatsoever, right? Just wait.

But what if we could take the offensive constituent (bergapten) OUT of the bergamot essential oil? Could we use it freely? It would be safe but would it still be a “natural” essential oil or it would be already contaminated with the horrible hands of progress, technology and human production and interaction rendering it unnatural or synthetic?

I am going to leave that question opened for now so we can jump into the aroma chemicals realm.


What are they?

Wikipedia tells us that “an aroma compound, also known as an odorant, aroma, fragrance, or flavor, is a chemical compound that has a smell or odor. A chemical compound has a smell or odor when it is sufficiently volatile to be transported to the olfactory system in the upper part of the nose.”

Basically, aroma chemicals are constituents or a mix of constituents that can be extracted from a) a natural essential oil (isolates), b) can be a chemical modification of these isolates or c) can be created in a laboratory from scratch from petrochemicals.

Let’s analyze this: As an example, several essential oils (coriander, palmarosa, sweet orange, lavender, and more) have among their constituents one that is a naturally occurring terpene alcohol named linalool. There are more than 200 species of plants and flowers from which linalool can be extracted as an isolate. Its chemical formula is C10H18O. These isolates can also be chemically modified to create other isolates. It can also be created from scratch in a lab, being the result EXACTLY the same as the one extracted from the natural essential oil. Hello! It even has the same formula C10H18O.

At the end of the day, that’s why it is called CHEMISTRY and it is a science, right? Ability to reproduce an experiment under the same circumstances…I don’t know you but for me, at this point, the word “natural” and “chemical” have a really dangerous or confusing border between them…

Truth to be told, the results are not exactly the same and the odor is slightly different as the molecule can exist as a d- dextrodextro - right handed or l- leavoleavo - left handed isomer which occurs in different ratios and other trace impurities will be present from the specific manufacturing process* (

Well, back to the aroma chemicals, the same way that you can re-create in a lab constituents that DO occur in nature (linalool, eugenol, etc.) you can also create something completely new that DOES NOT exist in nature.

Now, do some of these aroma chemicals created from scratch in a lab could be potentially hazardous to human health? Absolutely YES,exactly the same as some of the natural essential oils and its constituents. Luckily again, IFRA also studies aroma chemicals and suggest which ones should be banned and which should be used at low rates or with caution.

And that’s it! That’s the whole thing about yes or no to aroma chemicals! So why so many people are against aroma chemicals? Well, here is where ignorance and marketing claim their space. Let’s go one by one:


Some “natural advocates” claim that anything that has been transformed by a human process is not natural…Hmm…despite the fact that it sounds like a whim….if I apply heat to some H2O and boil it, the resultant vapor is not natural?. Give me a break! And by this standard: wouldn’t ANY essential oil be an un-natural product? I explained already how they are obtained and certainly SOMEONE has to actually do the distillation, extraction, expression or whatever method is used to obtain it.

And then I heard: human interaction is ok, but if you get a byproduct of such interaction, something that is different than the original, then, is not natural…and I went back to the example of the boiling water… [Frustration sight]

And then I heard that a physical transformation is ok, but not a chemical one…I even read that it has to go through a double transformation to stop being natural…nonsense.

I don’t know you folks, but for me, I think it is easier to embrace common sense than to create ridiculous and fictitious limits that accomplish absolutely nothing…unless there’s another interest around that we are not really aware of…

What leads us to…

Marketing, oh my:

Why “Natural” gets a YES and “Chemical” gets a NO? Why Mr. Chemical or Mr. Synthetic is the bad guy of the movie and Ms. Natural is the mistress in distress? Do you want the truth? Are you sure? Because you will not like it…Are you ready? Ok. Here it is:


Because we buy ideas without thinking.

Because they target some of the misconceptions of our own inner beliefs: that "synthetic" is toxic and "natural" is not, that "synthetic" is a copy and copies are bad.

Because we don’t understand that being natural is not necessarily safe.

Because we are over-saturated with information, especially now with an internet where everybody participates and emit opinion but we cannot elucidate who or what is right.

Because we like to repeat without checking facts.

Because “everybody says so” and that, my friend is the essence of what marketing is and does: To get everybody to say or think something. No matter whether is truth or not. (I told you, you wouldn’t like it).

And here, I am not a chemist but a marketing degree holder of a 5-year career in an accredited university. And you are more than welcome to argue this, but I truly think that marketing is not only that but broadly, the professionalization of common sense.

Remember how years ago margarine was awesome and butter was bad for you and suddenly butter was good and margarine was REALLY bad because of some trans-fat technical lingo that still today you don’t understand? What happened? Were we tele-transported from an alternate reality? Nope. We were “marketinged”. Someone decided that there was more money to be made in butter and slowly the discursive of the benefits of the butter/margarine duo were changed through marketing, in a way that seemed to be logic and with common sense.

If we add to all this that the “I am a mighty natural eco-person” today seems to be the fashion along with the green movement, global warming and every environmental crusade you can imagine, we can see and understand why and how easily we change our points of views based on the messages that we are exposed to on a daily basis. And most of them, we don’t even know if they are truth or not!

I think all you need to do is to use YOUR common sense, not the one that they want you to have. (The biggest paradox is that common sense is anything BUT common). Water is healthy but if you force 150 gallons down your throat, you could drown. Does water kill you? Of course not! But stupidity and lack of knowledge do!

Another way of analyzing Essential Oils vs Aroma Chemicals is by its advantages and disadvantages. (from

Essential oils:


  • Complex odors that add depth.

  • Superior Pharmacological activity.


  • Variable quality.

  • Some sources are not renewable.

  • May contain toxins or chemicals.

  • Components responsible for interaction and changes in color and odor are hard to remove.

  • Limited quantities when upscaling production.

  • Labor and land intensive.

  • Supply subject to natural cycles and phenomena.

  • Price varies and regularly increases in comparison to synthetics.

Aroma Chemicals:


  • Consistent quality

  • Generally stable prices (Decreasing in real cost)

  • Interaction with product bases or other ingredients can be controlled.

  • Simple clearer, controllable odors.


  • Poor consumer perception.

  • Dependent on the supply of source materials which are only by-products of much larger industries (viz. paper and oil).

  • Some industrial quality chemicals sold as food or cosmetic grades.


I truly try to respect those who claim to be embarked in a cleaner, healthier and purer way of life and those who fight for noble causes that apparently affect us all and for which, I agree, the time to act is now. But sometimes some things seem to be a little bit overboard and get out of hand

As instance, I know, tap water might be unhealthy and full of chemicals or bacteria or other things you don’t even want to think about and you have every right to say “I won’t drink it, I’ll go and buy some healthy spring water”. That is ok. But if you want to be coherent with your thinking, be sure that whatever you buy as “spring water” is not actually filtered tap water bottled with a fancy label. Ask. Read. Study. Question. That’s the only way to learn. And the only way of minimizing your chance of being an idiot because you just like to repeat other’s behaviors.

And please, DO NOT go to extremes. If you ever heard that the chlorine in tap water is dangerous and a health hazard for you, especially when you take a shower because you are getting it not only in your body through your skin (oh!....the larger organ of your body) but by inhalation of the vapors as well because the water is hot and blah, blah, blah.…investigate a little bit, Google it. Try to find out if it is true first. Make your own opinion. Don’t just repeat what you hear or read. Make up your own conclusions: Let’s give it a try by analyzing first some facts about showering: