F.A.Q

What are essential oils (EO)?
Essential oils (EO) are complex mixtures of volatile compounds that are characterised by important biological activities for the plant itself and for humans who have learned to exploit their properties over the centuries. Definition by Research on PubMED
EO are mainly characterised by the presence of terpenes/terpenoids and phenolic compounds (i.e., phenylpropanoids), that derive from the mevalonate/methyl erithrytol and shikimic acid pathways. PubMed Research
Research on PubMed/MEDLINE, 2023 data show that the multiplicity of pharmacological properties of essential oils occurs due to the chemical diversity in their composition and their ability to interfere with biological processes at cellular and multicellular levels via interaction with various biological targets. Their pharmacological profile includes antimicrobial, anti-inflammatory, antitumor, antioxidant activities, among others. Essential oils are composed of approximately 20–60 components at different concentrations, but some of them may contain more than 300 different substances.
The lipophilic profile of these components contributes to their ability to penetrate cells and tissues to reach biological targets and carry out the pharmacological response. The antioxidant activity of some constituents of EO suggests their possible action in restoring balance in pathological disorders associated with oxidative stress, including inflammatory and tumoral processes. The bioactivity in anti-infectious screenings shows the ease with which EO and their constituents cross the biological membranes of infected cells and/or microorganisms and cause their death. PubMed/MEDLINE Research
Nature provides plants with a wonderful gifts: with natural chemical compounds that are vital for the survival and protection of the plants. When essential oils are distilled right, are pure, unadulterated and consistent, these natural chemical compounds will remain in the essential oil, which will help us help improve our health and wellness.
Purity in terms of essentials oils can be defined as lack of adulteration.
Without purity you don´t know what you are putting on your body on your skin and and what goes in your lungs. Without knowing what is in the bottle you are not safe.
Consistency means that the potency of the chemistry in every drop is for all intents and purposes the same year to year and batch to batch.
Because of dosage. If a manufacturer of essential oils does not have consistency, then consumers have no idea how to dose essential oils to have the same effect time to time, year to year.
The adulteration of EO is not uncommon along supply chains, thus generating concerns in the EO industry. EO can often be adulterated via the addition of cheaper EO (e.g., sweet orange added to bitter orange, corn mint added to peppermint or lavandin added to lavender),  via the addition of cheap synthetic materials (e.g., synthetic linalool and linalyl acetate added to bergamot EO) or via dilution with vegetable oils. Research published on PubMed

In one word the addition of something to an essential oil or the fabrication of an essential oil by chemists.
The EO marketplace is rife with counterfeited, adulterated, or misrepresented products. A Research published at MDPI proves this statement and highlights the importance of the empowerment of individuals to recognise and avoid counterfeited, adulterated, or misrepresented products. Authentication and certified source is highly important.
Usually adulteration of the essential oil is done for the purposes of increasing the profit.
The essential oil industry as a whole is riddled with adulterated products. 
The natural chemical compounds found in the different parts of the plants, has been identified. The science of chemistry found simple ways to synthesise these chemical compounds. Producing the synthesised versions is highly cost-effective. However, researches show that they have no benefits to offer, the contrary the use of these EO are unsafe. In one word, as long as we do not know what in the bottle is, safety is never ensured.
It brings up concerns from a transparency, safety and efficacy perspective.
Some people want just a nice smell in their home and are happier paying that smaller price for that nice smell in their home. Cheap essential oils are fabricated, are not pure and are not consistent. People will not get safe and efficacious results by using them and that nice smell is going into your lungs. Without purity you don´t know what you are putting on or into your body.
The secondary market is so rife with adulteration that essentially you cannot have pure and consistent essential oil if you are purchasing it on the secondary market.
dōTERRA puts in tremendous efforts in making a pure and consistent essential oil, free of adulteration and with consistent chemistry that you can rely on, bottle to bottle, year to year.
You have to own your supply chain all the way through to gurantee that your customer will receive pure, unadulterated and consistent essential oil.
The main trend in the essential oil industry is something that is chemically indistinguishable from something that is pure and natural, but is not pure and natural.
It brings up concerns from a transparency, safety and efficacy perspective.
Peppermint essential oil is used in thousands of products. Peppermint essential oil is totally deconstructed in the industry down to its root components, through very fractional distillation tools that allows single chemical compounds to be taken out of the plant essential oil. They take all of these test tubes of single chemical compounds and reconstitute them back to fake, resynthesized, unnatural product.
dōTERRA is the only company marketing a birch oil that is not only pure birch, but has any birch in it. Birch on the bottle no birch in the bottle. The product in the bottle was either fabricated from wintergreen or completely fabricated from expired aspirin. Methyl salicylate is the main chemical component of both wintergreen and birch essential oil. A simple organic chemistry and aspirin turns into methyl salicylate. Highly cost effective. Might smell like birch, but has nothing to do with birch at all.
The International Standards Organisation sets standards also for the essential oil industry. The benefits of essential oils derive from their chemical composition. If the chemical composition is right the essential oil can have a positive effect. The International Standards Organisation sets the range of 20 % to 40 % for chemical composition. Meaning that one bottle can contain 40 % of active ingredient component while another one only 20 %.
Consumers need to be very choosy. The essential oils go in your lungs, on our skin and in your body, and affect your chemistry. These plants have been with us a long time, and if we do these plants, these essential oils right, they will help improve our health and wellness, but we have to be using a pure, unadulterated and consistent product.