Depending on the recipe, you’ll see different recipes use different concentrations (or percentages) of essential oils.
Recommendations on these percentages vary from source to source, but generally fall between 2–5%. Lower concentrations are generally recommended for children, infants, pregnant/breastfeeding women, and the elderly; generally from 1% all the way down to none.
However, it’s important to remember that the 2–5% number is really a very broad generalization. You can easily purchase 150+ different essential oils, and just like the plants they are derived from, these essential oils vary wildly. Think of essential oils a bit like the herbs and spices you cook with. A dish that is 5% cayenne pepper will be very different from a dish that is 5% basil.
Lavender and tea tree essential oil are often cited as being safe for “neat” (straight, undiluted) application—that’s 100% concentration. While I wouldn’t recommend doing that, people clearly do and there are no reports of loss of limb or life from doing so (though sensitization [developing an adverse reaction to something from exposure] can and does happen).
On the other end of the spectrum, some essential oils are crazy irritating, even in very small doses. Honey myrtle (Melaleuca teretifolia, a relative of tea tree essential oil) is one such essential oil. I added a couple drops to my bandits blend and then tried diffusing a few drops of the blend in my house. Within minutes my eyes were burning from across the room—from what might have been a drop of honey myrtle essential oil diffused throughout an entire room. That, obviously, is well below the 2–5% recommended “safe use” and was still intolerable.
The Government of Canada publishes and maintains a Hot List of prohibited and restricted ingredients for use in cosmetics. The banned list only contains two essential oils, neither of which I’ve ever seen for sale. The restricted list contains a few essential oils, including Eucalyptus essential oil, which must be used at concentrations of not more than 25%—substantially more than that “safe” range. Feel free to peruse the list yourself—it’s quite an interesting read (human placenta is on it…).
When we use essential oils we generally use them for scent/aromatherapy benefits, or for physical effects (and sometimes both, though one is usually more important than the other). Examples of use for scent include lotion, lip balm, and body butters. Examples of use for physical effects would be things like tingly foot rubs, tiger balm, and cramp salves.
When adding essential oils for scent, and to “taste” (of your nose, haha), I find it’s hard to surpass the “safe” range. You’ll find your product smells plenty strong enough well before your surpass 5%. Assuming 20 drops = ~1 gram (a rough approximation), that means you’d want to use 20–50 drops of essential oil in a 50g batch of lip balm to be within that 2–5% “safe zone”.
When using essential oils for a physical effect, we’re generally talking about a warming (cassia, chili seed), cooling (peppermint, menthol), or clearing (eucalyptus, camphor) effect, or some combination of the three. I have found that 5%> concentrations simply do not deliver these physical effects to the desired level. I’ve made tiger balm with essential oil concentrations from 30–50%, and the 30% stuff produces a very, very weak effect. A 50% concentration delivers the kick that you’d get from the shop-bought stuff, which leads one to assume the shop-bought (and government regulated) stuff contains a concentration of essential oils somewhere around 50%. The same can be said for shop-bought menthol muscle rubs. So, you will find that many of my “physical effect” essential oil recipes feature concentrations of essential oils well above 5%. This is why they work. I test them on myself, and never publish anything I find to be uncomfortably irritating. I also don’t recommend using these recipes while pregnant, or on children. All that said, these “physical effect” recipes use a fairly small selection of essential oils that are commonly found in shop-bought high concentration products—we’re generally talking about menthol, peppermint, chili seed, cassia, cajeput, and camphor. You won’t find recipes from me that are 10% Honey Myrtle essential oil, that’s for certain.
So… where does that leave us? You may want to do some of your own research. You are certainly more than welcome to reduce essential oil concentrations in recipes to suit your comfort level. However, if you’d like to keep all your essential oil use under 5%, I’d recommend staying away from the “physical effect” category of recipes—you’ll be wasting your ingredients.
Posted in: Safety