You've determined the purpose for an oil blend you want to make, now you're ready to decide on your ingredients - and every ingredient you include will make a difference in your blend.
The essential oils you choose for your blend can be based on what you have on hand, the aromas you love the most, therapeutic properties, and how they act on the skin (skin friendly or potentially skin damaging).
Your selection of carrier oils, including any herbally infused carrier oils, is just as important as your choice of essential oils!
Imagine you're making a roll-on blend for your muscles. While the essential oils are the highlight of the blend, the carrier oils are very important supporting actors because they may provide skin protection and/or healing properties as well as other therapeutic properties. Let's walk through the selection process.
For a warming effect, you might choose Black Pepper and Ginger. For a relaxing effect you might choose from Peppermint, Patchouli, Lavender, Roman Chamomile, and Geranium. These are all good choices for a muscle blend, but the Black Pepper, Peppermint, and Ginger may be hard on skin cells.
Peppermint may cause skin or mucus membrane irritation, and has other cautions with its use. Black Pepper oxidizes easily, and if it does, it could cause skin irritation or sensitization. If you have sensitive skin, Ginger may be irritating. This doesn't mean you shouldn't use these oils - they are all very good oils -- it means you should use them with care and in low dilutions. You can combine them with skin-friendly essential and carrier oils to minimize/eliminate potential irritation.
Patchouli, Lavender, Roman Chamomile, and Geranium are all very skin-loving oils that are great for relaxing muscles and can possibly mitigate the potential risk of skin irritation from the above oils.
A blend with low dilutions (2% max each) of Peppermint and Ginger for that warming and cooling effect combined with Lavender and Geranium would be a great roll-on blend for after exercising.
Now, it's time to decide on your carrier oil(s). Carriers are (imho) a whole other fascinating branch of study. You'll want oils that will absorb easily and provide their own therapeutic properties. Shelf life may or may not be important depending on how quickly or slowly you plan on using up your blend. Three quick-absorbing oils that come to mind are Grape Seed Oil, Hemp Seed Oil, and Jojoba Oil.
Grape Seed is a common oil used as a carrier because it's easy to find, reasonably priced, light, and absorbs quickly. It's chock full of vitamins and minerals, and has a flavanol that supports collagen and elastin (which are components of cartilage and skin). (Parker, 2018) The drawback with Grapeseed Oil is its shelf life. After being opened, it will last from 3 - 10 months (depending on temperature and air exposure) if stored without refrigeration. If refrigerated, it might last up to a year before going rancid.
Hemp Seed Oil (not the same as CBD oil) is another option in this blend. With what is considered to be a great balance of Omega 6 to Omega 3 Fatty Acids, its anti-inflammatory and skin-healing properties would compliment the blend. It absorbs easily as well. Hemp Seed Oil needs to be stored in the refrigerator and has up to a
1 year shelf life.
Jojoba Oil - which is really a wax - is chemically a close match to the sebum of our skin. It absorbs quickly, penetrates deeply, and moisturizes the skin. The 20 year shelf life and it's ability to extend the shelf life of the blend would make it a great choice; however, it's more expensive than Grape Seed and Hemp Seed.
All three of the above carriers are good choices, and mixing two or all three of them would enhance your blend.
This simple scenario demonstrates that as you make your own blends, considering the purpose of each individual ingredient is an important aspect of your creation.