What is henna?

Typically, "henna" refers to the leaves or powder from the leaves of the henna bush. Henna (Lawsonia Inermis) is one of many natural dyes. The pigment found in the leaves of the henna bush release as a dye when added to a liquid such water or something acidic, such as lemon juice. What separates henna from many other natural dyes, is its ability to stain the skin and hair more effectively, and for longer periods of time than most natural dyes are capable of doing. While the term "henna" is added to lots of products and ingredients used on hair and skin, it is important to seek henna that is 100% henna.That is 100% Lawsonia Inermis.

What makes henna beneficial to hair?
Henna provides two types of benefit to the hair simultaneously. Henna will condition and color the hair. As a conditioner, henna strengthens the hair. It is an anti-fungal, and reduces the occurrence of dandruff. It conditions the scalp, slightly loosens the curl pattern, and helps to detangle as well as make hair more manageable. As a natural source of color, henna colors the hair red. Not a bright cherry red, but rather a beautiful and natural red for hair.

How does henna color the hair?
Henna does not color hair like synthetic dyes. Henna coats the hair shaft with a transparent red coloring. As applications of henna are repeated, the color deepens. Henna does not and cannot lighten hair. However, it can provide on dark hair, red and reddish highlights. Henna on black and dark brown hair will eventually become dark auburn to burgundy/black with red highlights in sunlight. Henna on blonde hair can shift to a natural red. Henna on red hair will make the hair a deeper richer red. Henna on brown hair can range from a natural red to auburn, to dark auburn depending upon the shade of brown. Henna on white hair will make the hair a natural red to deep red. A benefit to using henna is that it will both condition and color your hair in a way that is both natural and safe.

How often should henna be applied?
Most people use henna once a month.once every 4 weeks. Henna can be used safely more often. However, it is not necessary to use it more frequently for the coloring and conditioning benefits.

Once you apply henna, will it always be on your hair strands, or will it eventually wear off?
Henna eventually fades out of the hair and off the hair strands. Its effect is temporary. This is why in order to maintain the effects of the henna, applications must continue. Without repeat application, henna coloring can be entirely gone in 3-9 months. Its various conditioning effects wear off at different rates. For example, henna loosens the curl pattern of the hair. However, as soon as
you wash your hair, the curl pattern reverts to your normal curl pattern. You need and want repeat applications of henna monthly to maintain the strengthening effect on your hair. Bottom-line, whatever the effect of henna on your hair, it is temporary rather than permanent.

Can henna be applied on top of previously color-treated hair, hair that has had chemical services, perms, thermal reconditioning or relaxers?
Yes and No... Yes if you are using 100% natural henna powder (Lawsonia Inermis) or a 100%
natural herbal/henna powder. If you know who you are purchasing your henna from and trust the information they provide about the henna powder they sell, ask them if their henna is 100% natural henna powder or a 100% natural herbal/henna powder. The person you purchase your henna powder from should know what they are selling. If you think they do not know what they are selling intimately. Intimately means that they import it directly.then pass on purchasing from them. Because. this is where the no part of the answer comes in... No you can't use "henna" over previously chemically treated hair if what you have is a henna compound or a henna product with ingredients you don't know about or can't pronounce. The one exception to the use of henna with these products would be using henna with any of the semi-permanent hair colorants that contains metallic salts or metallic dyes. It is again these metallic salts and metallic dyes that are of concern. The metallic salts and metallic dyes are used in many semi-permanent hair colorants and should not be used with henna or with previously color-treated hair, hair that has had chemical services, perms, thermal reconditioning or relaxers. The reason is that the metallic dyes and metallic salts react with the neutralizers used with perms and relaxers and also with peroxide used with many hair dyes.This reaction can cause damage to both the hair and scalp due to the intense heat that can be created during the chemical reaction. These same metallic dyes will alter the color results of most synthetic or natural dyes and can produce quite strange hair colors as a result.typically dark brown, black or green!!!

How often should henna be applied?
Most people use henna once a month.once every 4 weeks. Henna can be used safely more often. However, it is not necessary to use it more frequently for the coloring and conditioning benefits.

For those who find the process of traditional powdered henna too messy
to apply, are there any other henna options for them?
For both the coloring and conditioning benefits of henna, there is no way to avoid the paste and its
nature. Using henna requires preparation and time. It doesn't fit well in to a busy hurried life style. And the faster one tries to use their henna and apply their paste and rinse out their paste, the messier it becomes.the more frustrating the process and the less satisfying the results. Using henna requires a "change of mind." It requires the same sort of change of mind and provides similar satisfaction to switching from instant coffee to brewing your own coffee from freshly ground coffee beans that you selected in order to have the experience you desired. There is something about smelling coffee brewing and permeating your home that reminds you that somethings are to be savored and sipped and not rushed.

Source:http://www.everydayhenna.com/interview1.html