HENNA: What is it, and what does it do?

Henna is the name given to the dried and powdered leaves of lawsonia enermis, a plant that grows in Egypt, India and parts of the Middle East. For thousands of years it has been used as a colorant to stain human hair, nails or skin a bright fire-engine red color. In literature, this orange-red color is often referred to as “henna red”. The ancients combined henna with other natural colorants like indigo, iron oxide or lead salts in order to produce brown and black colors. The Old Testament describes Solomon as using henna and indigo to stain his beard.

Benefits of Henna & How To Use It on Your Hair
Today people still use henna to color their hair. It is a natural coloring agent without the potential health hazards posed by the synthetic coal tar derivatives, many of which are potentially carcinogenic. Furthermore, a henna treatment leaves the hair excellently conditioned, with added body and superb shine. In fact, the conditioning properties of henna are so desirable that treatments with “neutral” henna are very popular. “Neutral” henna does not impart any color, only conditioning.

When using henna, the following procedure is used. The henna powder is first mixed with water to the consistency of a thick paste. This paste is then applied to the hair wherever coloration is desired. The longer this “henna pack” is left on the hair the more color is transferred. Heat can be used to further hasten the coloring. When the desired color is achieved, the henna paste is removed by washing and the process is complete.

The Chemistry of Henna & How it Colors Your Hair
Henna contains a chemical molecule called lawsone, which is responsible for the coloration. Lawsone by itself is colorless. However when exposed to sunlight or to air, it is converted to a new compound that has the characteristic red color. In its natural state, that is to say when imbedded in the vegetable matrix of the henna plant, lawsone is protected from the environment and thus is colorless. When henna is applied to the hair, the lawsone is transferred from the vegetable matrix of the henna powder into the matrix of the hair shaft. Lawsone is a very small molecule and thus can penetrate deep into the nooks and crannies of the hair shaft. When the henna paste is rinsed off, the lawsone remains behind and immediately reacts with the environment and turns red. The hair will be colored red. The exact hue or degree of “reddishness” will depend upon the other natural pigments present in the hair and, to some degree, the condition of the hair prior to the henna treatment. These secondary factors make coloring hair with henna a very unpredictable procedure and is one reason why many hair stylists do not use henna. Normal healthy hair gives a nice even brassy red hue. Bleached, processed or otherwise “roughed-up” hair gives unpredictable results because the absorption of lawsone is very irregular.

Problems with Henna Treatments
Besides the unpredictability of the final color, another common complaint about henna treatments is that if done too often henna builds up and makes the hair brittle and easily breakable. In order to understand this complaint, first be aware that the materials in the henna that are being transferred to your hair are not very water soluble. That is to say, they would much rather associate with the solid vegetable matter of henna powder or with the protein matrix of human hair than with water. It is for this reason that very little water is used when preparing the henna paste. If too much water is present, it actually acts as a barrier and prevents transfer from the henna onto the hair. In a henna treatment the substances being transferred onto the hair are the non-water soluble materials that are responsible for the coloring and conditioning effects of henna. Consequently, because they do not dissolve in water, these materials are not easily removed with subsequent washings of the hair. And with each additional henna treatment, these materials can build up and do indeed make the hair brittle and easily breakable. For this reason, it is recommended that no more than one henna treatment be applied every 3-4 months.

What Makes ShiKai’s Henna Different?

A Special Process That Removes The Build-Up
At ShiKai we have developed a unique procedure for processing neutral henna powder by which we are able to completely separate and remove the non-water soluble materials. We can thus get rid of all of the materials that tend to build up on hair and make it brittle. To do this, we first blend the raw henna powder with a large volume of water. This forces all of the undesirable materials to remain within the henna powder while allowing all of the water loving materials to be extracted into the water. With proper pH adjustments and filtration techniques the solid henna materials can then be isolated and removed. The remaining liquid is now totally free of all materials that can build-up.

The Goodies That Remain
The water soluble materials that remain are very different from the non-water soluble materials that a henna treatment deposits into the hair. First of all, the water soluble materials are mostly small to medium size molecules. When applied to hair they simply stick to the surface of the hair shaft. This coating makes each hair shaft ever so slightly thicker with the result that the hair overall appears to have more body.

Chemically, these compounds are small chain polysaccharides – very similar to natural cellulose. And like cellulose they also are able to brilliantly reflect light. Consequently, this coating not only adds body to the hair but also produces a lustrous shine. But best of all, these water soluble materials cannot build up on the hair shaft. They would much rather dissolve into the rinse water of a subsequent shampooing than remain on the hair. The only way to force them to remain on the hair is to incorporate them into a shampoo so that they can be redeposited with every shampooing.

No More Complaints From The Hairdresser
A common complaint that hairdressers have about working on henna treated hair is that it does not take a perm very well nor can it be color treated easily. The coating that henna leaves behind interferes with both these processes. Invariably the hair must first be washed with a very strong shampoo such as a “clarifying shampoo” in order to strip off this coating. Usually this process must be repeated several times.

This build up is not a problem with our Henna Gold and Salon Naturals Shampoos. The coating that produces the cosmetic properties to the hair is very easily removed with even the mildest shampoo. Recall that this coating is highly water soluble and even a simple rinse with clean water will remove most of it. The customer need only wash his or her hair with another shampoo before getting a salon treatment.