Essential oils function as a solvent in your paste and help the dye molecule to be more available to attach to keratin in skin. Most solvents that come to mind first are things like kerosene or turpentine. Obviously they are not skin friendly and we don’t want them in paste! (That doesn’t mean that they are not sometimes found in imported pre-mixes! BEWARE IMPORTED PRE-MIXES!) There are solutions for skin friendly solvents and we can find them in essential oils with high levels of monoterpene alcohols. This is where the term “terp” comes from.
Terps certainly improve the color and duration of henna, some more than others. Here are a few photos that I took of my own experiments a good ten years ago. I couldn’t even tell you know things like where the oils were purchased or what kind of henna I used, but it does serve to show that there can be a significant difference!
Every essential oils is made up of many chemicals that plants use as communication systems. These chemicals do things for the plant like mimic the pheromones of insects that would help with pollination. It really is a very intricate and amazing arrangement! Most of those chemicals are monoterpenes. Its the monoterpene ALCOHOLS that help us out with our paste. Its also important to point out that some monoterpene alcohols or essential oils containing them can be irritating or even toxic! Its important to choose carefully!
Which monoterpene alcohols?
The most effective, nontoxic, non-iritating monoterpene alcohols are terpineol, geraniol, cineol, cedrol, linalool. Lavender essential oils have high levels of linolool. Tea tree has cineol. Cajeput and Niaouli both have high levels of cineol and terpineol. Geranium has geraniol and linalol. Clove has high levels of eugenol. You may be asking how one knows this stuff! Since these are natural constituents of the oils, its not like they’re written on the bottle right?! Well, if you want to experiment rather than relying on the wisdom of those that came before you, I absolutely respect that! There are a few things you’ll need to know first.
You’ll need a great essential oil book that lists the most common chemical constituents of essential oils. This won’t be perfect because plants are effected by variables like the temperature and soil that will make them slightly different season to season and location to location. They will give you a good idea of the constituents that are most present in an essential oil, usually listing them from the largest percentage to the least. I use the Illustrated Encyclopedia of Essential Oils by Julia Lawless. Between home remedies, soap making, and henna research I use this book every day. It was an excellent investment.
Having a good essential oil guide will help, but there are a few other things to know that will help you shop for oils intelligently and even to experiment with different oils in your paste. First of all, just because an oil contains the good monoterpene alcohols, doesn’t make it a good oil for paste! Camphor, for example, is full of cineol and terpineol, BUT its also toxic because of other chemicals naturally present in the oil. Also, plants with similar names are NOT equal. Clove bud makes a perfectly fine terp (although can be irritating to some, so use it in small amounts) but clove leaf is a strong irritant! You should also know that sometimes essential oils are improperly labeled. Eucalyptus Globulus is a great terp and non-iritating, but other varieties are not, however I have often found essential oil labeled “globulus” that turned out to be a different variety all together. Quality can be a serious issue too. Depending on how the oils are distilled, toxins involved in the extraction can be left behind. To avoid this, make sure to get “food grade” or “aromatherapy grade” essential oils that are pure, not diluted. One last thought on oil choices: Even the same species of plant can be different from one source to the next. Lavender is a perfect example. Even though they are all True Lavender, lavender from France (or fine lavender) has much lower levels of monoterpene alcohols that that grown in Hungary or Bulgaria.
There’s a lot more to discuss on this topic! I’ll write more about it later, but to sum it all up, you can use oils from a trusted henna supplier and feel confident that you’ll get good color safely. If you want to step it up a notch, you may want to experiment with other oils that aren’t used as commonly. Basil and Juniper berry might be good choices! But either way, it is vital that you do your own research when using oils to make sure that you are using them safely and always make sure your clients are aware of the oils you choose. Some folks may be allergic to some oils. They may interact with conditions or medications. Rosemary oil can induce early labor! Make sure you know your oils! Also don’t over do it. You should look at essential oils like medicines, that can be harmful when too much is used. I’d never recommend using more than 1 oz (2 tablespoons) per 100 g henna powder.
Playing with essential oils can give you an opportunity to really customize your paste AND improve color. Just make sure to do it responsibly.