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How Essential are Essential Oils?
On the rare occasion that I bake something from scratch, I don’t often think about why the baking powder is necessary. I know that without it my cookies will be small, hard lumps, but to be perfectly honest, I haven’t really pondered the chemistry of it since high school science. Many of us likely look at our henna recipe in a similar light. We know that essential oils add kick to the paste, but why? What’s really going on in there? And don’t forget the best question of all — which oils work best? What are Terps and what do they do? Did you know that henna is hydrophobic (tending to repel, or fail to mix with water)? The rather unexpected truth is that water (or any other water based substance) is not the best way to break up the plant matter to release dye. What we need is a hydrocarbon solvent, but we need to be very careful about it. Some hydrocarbon solvents are gasoline, kerosene and turpentine. While these probably do a fantastic job setting the little dye molecules free, we cannot use them in henna paste because they are very dangerous. They are toxic, have harmful fumes, and can damage skin,. Essential oils are made up of many different carbon- and hydrogen- based compounds called terpenes. Some of them are hydrocarbon solvents. Terpenes attached to a hydrogen atom and an oxygen atom are alcohols. Alcohols are usually safe in that they have little to no toxicity. Mono terpene alcohols that have been found safe and effective in henna paste preparation are terpineol, geraniol, cineol, cedrol, linalool, and to a lesser degree eucalyptol and citronellol. Adding essential oils with high levels of these components can really improve the potency of your paste by making more hennotannic acid, the dye in henna, available to the skin. Henna artists call these oils "terps." Prove it... Let’s start with what we know. Many henna artist use Cajeput, Lavender, and/or Tea Tree essential oil in their mix. We started by experimenting with these oils. 4 oz. paste was mixed from Indian henna powder, lemon juice concentrate, and a little Dextrose, and left standing for 24 hours in 70ºF. This paste was then divided into 4 separate bowls, each containing 1 oz. of paste. To one bowl we added 1 ml tea tree essential oil, to the second 1 ml cajepute essential oil, to the third 1 ml lavender essential oil, and the fourth was left as a control. All four bowls of paste were re-covered and left standing another 8 hours. The paste was on the skin for 8 hours, and was not sealed. The results are found below. | |||||||||||
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These photos were taken 36 hours after removing the paste. The tests are on 3 different people. One was on a back, one was on a palm, and the third was on leg. It's not surprising that in all three tests the segment with no essential oils is the faintest. In the test on back skin there was hardly any color at all without terps! I was surprised to find that the tea tree oil segments were visibly lighter than lavender and cajeput. This is especially noticable in the photo of the palm. All this time I was willing to tollerate the stink of tea tree oil because it was the best terp! While I personally find lavender to be the most pleasant smelling of the three oils we tested, it seems that cajeput does the best job in at least 2 of the 3 tests. Please keep in mind that the quality of essentail oils can very greatly from one supplier to the next. There are many variables that affect the content of monoterpene alcohols in an essential oil. The oils we have tested here are the same as those for sale at Body Art by Jen. If you reproduce these test with oils from other suppliers the results may vary. It seems that terps really do make a pretty profound impact on the color of stain we can achieve. We will be adding more oils to this page as we test them. Please stop back soon. If you have conducted any similar test, please email your photos to post here. New Oils........ Added May 1, 2006
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We've just added a selection of 6 new oils and here are the initial test results. I was surprised to see how well basil performed. It seem to be nearly as effectice as the old-stand-by cajeput. Ylang Ylang is best used in combonation with other oils, but it is a viable terp, even if to a lesser degree. While this particular Ylang Ylang showed only subltle improvement on the color, I have seen much better results in the past. I will continue to explore other varieties and suppliers for the perfect Ylang Ylang!!! Cypress was also interesting. It didn't seem to darken the color much, but it did seem to bring out the red tones more than the other terps. I plan to experiment with this more in the future. Geranium faired well of course, but in this test Niaouli came out the leader. Niaouli is very much like cajeput in scent, but to my nose is a little more mild. Click here to order any of the oils we've tested.
Resources Thaunoo, Priya D. and T. Bahorun. Jan 22 2003. “Terpenes and their Derivatives” University of Mauritius. 1 Mar. 2006. <http://vcampus.uom.ac.mu/upload/public/2003122103128.pdf> Dummies.com. “Understanding Essential Oils.” 2006. 1 Mar. 2006 <http://www.dummies.com/WileyCDA/DummiesArticle/id-496,subcat-MIND.html> Cartwright-Jones, Catherine. The Henna Page “’Terp’ your Henna for Fast Safe Dark Stains” 2003. 1 Mar. 2006 <http://www.hennapage.com/henna/how/terp.html> Txilar, Niko. The Henna Page “Terps” 2003. Mar. 1 2006. <http://www.hennapage.com/henna/how/terp.html> Morgan, Alex, Catherine Cartwright-Jones, and Marianne Marsland. The Henna Page. “Essential Oils, A Users Guide” Oct. 2002. 1 Mar. 2006. <http://www.hennapage.com/journal/issue_III/article_3/page1.html> “Chemical Constituents of Essential Oils.” Healing Diva. 2000-2004. 1 Mar. 2006 <http://healingdeva.com/selena2.htm> | |||||||||||
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