You think you might be interested in working with essential oils, creating your own blends, and maybe becoming a certified aromatherapist. You're wondering what's involved - what you need to learn. In a nutshell, there's science, art, communication, basic math, and joy. Before you panic, it'll be okay!
For those just starting out, the most likely scenario is that you'll begin by looking at the therapeutic properties of some oils (whoa, science).
That's how I started - I made an index card for each oil and listed the therapeutic properties and any warnings associated with that oil. I spent about eight weeks just researching and learning new terms before I acted on the information.
I was interested in making a blend to help with my chronic pain. I used my index cards to select and buy individual oils for that purpose. Since I'm a nut about safety, I chose oils that had no precautions as far as I could tell. I also looked at oils to help DH breathe more easily and quietly at night. At the time, my thinking was "more is better", so my first blends tended to have many oils at a high percent. As my research (and then my formal studies) progressed, I came to understand that fewer oils at a lower overall percent worked better than a bunch of oils at a large percent. Eventually, I started learning about the chemical compositions of oils and how the chemicals work with our bodies. Wow, this anecdote is already including the science, art, communication, and basic math.
Let's take a look at the science involved in aromatherapy. There's anatomy and physiology - you need to have an understanding of the systems of our bodies and how they work in order to create blends to support those systems. For example, our skin is made up of three layers, and each of those layers are made up of more layers. Skin is part of the integumentary system, which is the body system that acts as a barrier to protect us from everything around us. If you rub your shirt on your skin, the material doesn't absorb into your skin; however, if you rub a drop of Grapeseed Oil on your skin it does absorb. How does the skin know what to let in and what to keep out? Learning about and understanding the Biology of our bodies and of the plants will be a significant part of the scientific studies in aromatherapy certification. Chemistry will be just as important.
Essential oils are made up of natural chemicals, so there is a lot of chemistry involved. Understanding how the different chemicals work together and affect our bodies is a part of making blending decisions. Wintergreen is a good illustration of this. The primary constituent (chemical) in Wintergreen is Methyl Salicylate which is very similar to aspirin both chemically and therapeutically. There are also precautions associated with it, namely, don't use it: if you're taking blood thinners or have a blood clotting disorder; with children; are allergic to aspirin; have GERD; before surgery; or are pregnant or breastfeeding. It should only be used in low dilutions for short periods of time because it may build up in the body and can reach toxic levels - especially if you're concurrently using several products that contain it.
Wait, what do I mean when I say low dilutions? Here's where the math comes into play.
Pure essential oils are strong concentrations -- too strong for our bodies when used topically. We need to reduce their strength to a level our bodies can handle by mixing them with another substance -- usually a carrier oil or a plant butter. We might make dilutions that range from 0.25% for young children up to 10% for topical use in acute situations, or not dilute at all for diffusion blends. We'll need a system (or two) for measurement as well. In the US, we tend to rely on ounces, but scientifically, milliliters are used. Simplified: 1 oz = 30 mL ≈ 600 drops. [≈ means about equal.] So, to make a 1% dilution is to use 5 - 6 drops of essential oil in 1 oz (or 30 mL) of carrier oil. I'm really not hedging here, drop sizes are not all equal!
The other part of the math comes in when you decide to start your own business!
All of this sounds like a lot of serious science and math -- where does art enter into aromatherapy? This is imho, the best part (though I have to admit, I find the science and math part fascinating too). The art is in creating new blends, in finding combinations of oils that smell delicious and help us stay healthy, in using energetics to create synergy between the plant parts, the plants themselves, and the chemicals to benefit others. Experimenting with different oils and oil combinations is also an art! And this leads us to the communication part of aromatherapy.
As you explore this wonderful ancient - yet new - realm, you'll learn tons of new vocabulary (which, I promise, will become second nature to you). You'll ask questions and discover new ideas and hypothesize new possibilities. Okay, okay, I know this sounds lofty, but it really is true. Most importantly, you'll need to keep notes on the recipes you develop and how they work. You'll want to share your successes and your failures with others. For some, just creating and using blends will be enough; others will want to shout from the rooftops "Look what these incredible plants can do!"
(Can you feel the joy here too?) ;)