As you can see, the choice for the right essential oil brand can be very convoluted. There are so many brands on the market, it can be hard to sift through the duds to find the right ones. The key is taking a step back and listening to what the companies are saying. You should also make sure to read the labels, your essential oil label should say 100% pure and not “blend” or “with jojoba/almond” as that means they are already diluted and not just pure essential oil. According to The East-West School For Herbal and Aromatic Studies, some of the qualities that you want to look for in an essential oil supplier are:

There are some essential oils that can be ingested in very small amounts. For example peppermint oil capsules, which help IBS symptoms. I have used Young Living essential oils and they are of very high quality. Whatever people decide to do it is important to remember that essential oils do not disperse into water and therefore even the ones that are safe to ingest need to be taken with a dispersant drink, like milk or within special capsule. It is advisable to consult a professional in any case. All the best.
Let’s address the issue of ‘health advocates’ giving out prescriptive advice of essential oils. I mentioned that I will sometimes prescribe internal essential oils for short periods of time.  As a qualified health herbalist and naturopath, I have an intricate understanding of human anatomy, physiology, and metabolism. I can look at research and decide on the safety profile of a new medicine before I prescribe it to my patients. Although essential oil health advocates are well-meaning (I truly believe they are) they simply are not qualified to be giving out health advice. I’m actually fine with them recommending certain oils and blends for diffusing, but I’d even be cautious to take advice on topical applications from someone who was not trained in aromatherapy. I’ve seen countless facebook posts of well-meaning advocates recommending everything from the neat (undiluted) use of essential oils on children, essential oil ‘cocktails’ with 2-3 drops of each oil (I’m not kidding). I’ve also heard countless horror stories of rashes, irritations, diarrhea and headaches from use.
Lisse essential oils purchases their products from distributors around the globe. Sourcing essential oils from foreign countries is common practice in today’s essential oil marketplace. It allows each plant to grow and flourish in its natural environment before it is harvested. Lavender originates in the Mediterranean, Myrrh is sourced best from the Middle East or Africa, and Sandalwood is originally from India. True essential oils have to come from their country of origin to be their most original variety. Lisse essential oils are 100% pure and routinely tested for quality. You can request test results on their website.
The action of C. sativum EO against planktonic cells of C. albicans stood out from others EOs showing the lowest MIC values against the oral microorganisms investigated. The crude C. articulatus oil showed the highest inhibition on the cells adherence and consequently in the biofilms formation. The oils from these plants can be considered as new sources of antibacterial agents with great potential against oral pathogens.
Regard to the inhibition of biofilm formation in the presence of 1 mg/mL of EOs and fractions (Table 6), the fraction F2LS and the oils from A. gratissima and C. articulatus demonstred the highest inhibition, respectively, on F. nucleatum (62.29%) and P. gingivalis (44.41%), S. mitis (9%) and C. albicans (28.08%) and S. sanguis (63.96%). Since no significative difference (p ≤ 0,05) was observed between the action of the C. articulatus crude oil and the fraction F2LS against F. nucleatum and P. gingivalis biofilms, the crude oils from C. articulatus and A. gratissima was chosen for further assays in the range of 0.0048 – 1 mg/mL (Table 7). In this condition, A. gratissima inhibited the formation of S. mitis biofilm only at 1 mg/mL (9%), even though this activity was superior to that of the chlorhexidine. On the other hand, the biofilm inhibition by C. articulatus oil was proportional to the concentration employed, and also similar or superior to standards used.
In fact, the doTerra peppermint oil contained ethyl vanillin which is a synthetic compound used for odor! So much for unadulterated oils. You cannot tell how potent, pure, or good an oil is by how beautiful it smells. Some don’t smell anything like you would expect. All of the peppermint essential oils that I have owned smelled like the peppermint that you find in a garden while doTERRA’s peppermint essential oil smells like peppermint candy.
And if you’re not up with what goes on… I keep seeing recipes including essential oils and it drives me crazy. Why use pepper when you could use pepper oil? Why use thyme when you could just add a drop of oil! I even saw this awful recipe for kids ‘immune boosting’ pancakes with On Guard, an essential oil blend that contains herbs like clove, cinnamon, eucalyptus, and oregano. Giving young children essential oils internally is in my opinion negligent and dangerous.

Most flowers contain too little volatile oil to undergo expression, but their chemical components are too delicate and easily denatured by the high heat used in steam distillation. Instead, a solvent such as hexane or supercritical carbon dioxide is used to extract the oils.[10] Extracts from hexane and other hydrophobic solvents are called concretes, which are a mixture of essential oil, waxes, resins, and other lipophilic (oil-soluble) plant material.