Essential oils are usually lipophilic (literally: "oil-loving") compounds that usually are not miscible with water. They can be diluted in solvents like pure ethanol and polyethylene glycol. The most common way to safely dilute essential oils for topical use is in a carrier oil. This can be any vegetable oil readily available, the most popular for skin care being jojoba, coconut, wheat germ, olive and avocado.[32]
No, DoTerra has NOT “done research. They are a multi-level marketing company using false claims about products. They pretend their products are the “most pure”, they invented a phrase indicating they are certified when they are not, and they are actually telling people – against ALL evidence that this is safe – to INGEST some of the oils. Stay away.
The term ‘therapeutic grade” essential oils is both false and misleading. The term ‘certified therapeutic grade’ was actually created by um… doTERRA, who then registered the name and then told the world that all other essential oils were not as ‘pure’. They even go so far as to call them ‘better than organic’. And just to point out, their oils are NOT organic, which would make them free from pesticide residues,  genetic modification or irradiation. There are many oils on the Australian market that are just as good if not better quality than those sold by doTERRA and Young Living. This does not make them universally safe to ingest, which brings me to my next point.
Marketing …ain’t it grand?! I totally agree with Amanda. But that doesn’t matter, because Young Living (and DoTerra) disciples won’t listen to science, or people with proper chemical/alternative medical training. On every forum, YL users, nay followers, stating with absolute certitude that only YL oils are pure: oddly people using Mountain Herb, Now…or other brands, don’t really care if others use ”their” brand or another, because they don’t have a stake in selling that brand unlike YL, no compensation plan. These people have a financial stake in YL. Every one of us uses our favourite brands, however we retain critical thinking therefore are open to suggestions/improvements unlike these aforementioned disciples of YL, that cannot see anything beyond ”their” brand. That in itself is a red flag.
Please don't fall into the old frequency trap that has been circulating around the internet since the 1990s. The problem with all this is that 99% of people don't understand quantum mechanics well enough to be able clearly see through the scam, or if they do suspect its a scam they don't have the background to articulate why Its a scam so they just don't comment at all. It is well known in science that molecules are constantly absorbing and emitting electromagnetic radiation of various types and many different frequencies. But the way that the typical eo frequency scam is described makes no scientific sense at all. I think part of it started as a way to sell high priced and useless frequency measuring equipment.
One of the keys to producing the highest quality essential oils is to have the highest quality growing conditions for the plants prior to extraction. For that reason, ZEVA focuses on sourcing our plants from indigenous regions where the growing conditions are ideal for the plants, rather than trying to force them to grow in a non-native, less hospitable environment. Our team works with suppliers from around the world to find the highest quality ingredients to go into every essential oil we produce.

Thanks so much for your article. I am having a huge issue battling against the whole “therapeutic grade” malarky put out by several big name companies. It seems even though it is a subjective title, and many other similar titles like it are in fact trade marked, that somehow people just buy into the idea that it MUST mean the oils are better. I am a huge proponent of high quality oils and knowing the company, their standards, distillation processes etc. But these empty titles really drive me nuts! Thanks for your writings!

I use peppermint EO after brushing my teeth on my tongue…it lasts so much longer than mouthwash, but is it safe to do this? I just take a couple of drops and rub it all over my tongue. I was concerned, however, after reading this article. Is the way I’m using it considered taking it internally? And, is it dangerous to do this since the oil has not been diluted in a carrier oil? Thanks!!

Essential oils have been used on humans for thousands of years. As a result, they don't fit into the conventional clinical science approach of testing a substance in the lab first, then on animals, and then on humans. As a result, if a researcher proposes to test an essential oil with humans first, they may be turned down. This is because research review boards tend to approve research studies that follow the more usual scientific research path.
Essential oils are generally extracted by distillation, often by using steam. Other processes include expression, solvent extraction, sfumatura, absolute oil extraction, resin tapping, wax embedding, and cold pressing. They are used in perfumes, cosmetics, soaps and other products, for flavoring food and drink, and for adding scents to incense and household cleaning products.