Aromatherapy and Dilution Rates
Ever notice how dilution rates are often cited in aromatherapy formulas and recipes yet it is often vague on how the rates were derived? This has always gotten to me so I decided to look into it.
Aromatherapy and its use of essential oils is varied by modes of application: olfaction, inhalation, RESPONSIBLE internal use (e.g., suppositories, enteric capsules) and the dermal pathway. Dermal usage is vast: neat application, frictions, oils/lotions/creams/serums, baths, scrubs/glows, roller ball applicators. (Note: I do not get into dilution for internal use here.)
Think about it. Essential oils are precious resources. They are POTENT, VOLATILE MOLECULES. The aromatic plants do not produce their essences 24/7, 365 days a year. The aromatics create essences at certain times of the day and at certain times of the year–and overall, each plant does not produce a whole lot of essence. Lavender (Lavandula angustifolia) may be harvested twice a year, a sandalwood (Santalum album) tree must grow to be FORTY years old until it can be CUT DOWN to take its heartwood. To obtain 1 kg of essential oil you need the following: 20-30 kg of fresh Zingibere officinalis rhizome, 150 kg of Lavandula angustifolia, 40-90 kg of Cymbopogon citratus/nardus, 1 ton of Helichrysum italicum, 5-10 tons of Melissa officinalis. Their potency deems it necessary to dilute them.
Let’s get onto dilution rates. It all comes down to number of drops.
Not grams or milliliters but the ever so unscientific number of drops–but this is ok. Aromatherapy is an art and a science about communication–so drops as a base and guideline are just fine.
- There are 20 drops of essential oil in 1 millilitre.
- The “drop” is pretty standardized through orifice reducers, droppers and pipettes. (Were you into repeatable manufacturing you would weigh materials anyway.)
- 30 ml = 1 ounce
- 1 ounce is 600 drops
If I want 1% dilution:
- 30 ml = 1 ounce = 600 drops. 1% of 600 is 6.
- That translates to 6 drops of EOs to 1 ounce of carrier.
Following is a table that uses “# of drops” as the base of the whole table:
|# of drops||ml||oz.||0.50%||1%||2%||2.5%||3%||5%|
How to read the table:
- If you want to make a 2 ounce bottle of body oil and use the holistic aromatherapy rate of 2.5%, you need 30 drops of essential oils.
- If you are making a 4 ounce batch of all-purpose salve, consider using a 3% to 5% dilution rate–that’s 72 or 120 drops of essential oils, respectively. (Note: wax holds the oils in a certain way and it’s OK to use this much essential oil.)