On this page you will a listing of common questions about henna and the mechanics of it. For further study I have posted links at the end of each section that you can refer to. A big thank you to Catherine Cartwright-Jones for granting permission to display the links to her website.
What is Henna?
Henna also called Lawsonia inermis is a small tree/large shrub that grows in the dry desert regions of the Middle East, India and North Africa. Henna is a desert plant and thrives on hot and dry conditions. Henna plants prefer temperatures that are above 50 degrees Fahrenheit. The hotter and dryer the season/growing region is the better the henna quality will be. The henna leaf itself is harvested in the Juvenile stage of 2 years or under. The youngest plants contains the highest concentration of the orange dye molecule Lawsone. It is this molecule that bond with protein based surfaces such as skin, hair, fingernails and some textiles to produce the henna stain. The highest levels of lawsone are in the petioles (veins) of the leaf.
Once the leaves are harvested they are left out to dry, the stems and leaves are then separated. The clean leaves are then packed into bags and sent off to plants for milling. Once ground the henna is packed and then sent off to distributors to export out.
How does henna stain?
In order for henna to stain the lawsone dye must be released by an acidic mixture. A common method to do this is to blend the henna powder with warm black tea, lime or lemon juice and essential oils such as tea tree, eucalyptus or lavender. The black tea is reputed to help enhance the staining ability of the lawsone dye. Lemon or lime juice are the acidic base that releases the dye and adding different essentials oils help to enhance the staining abilities even further. Depending on the type of henna used and the region where it is grown can determine how long it takes for the dye to release. Some take a few hours, some take a day or so. Once the paste is ready it is then transferred into rolled henna cone or plastic jaq bottle with tips fitted on the end.
Before applying the skin is usually cleaned with a toner or alcohol based spray to get rid of any lotions or skin oils that have been applied/developed. Skin oil and moisturizers tend to hamper the ability of the lawsone dye to stain darkly. Dry thick skin is perfect for producing dark stains. When applied to the skin the dye begins to soak into the skin cell layers in a straight down fashion. The henna is then left on as long as possible with a sealant such as lemon juice/sugar mixture or even extra hold spray gel with glitter. The warmer your skin is and the longer the henna can remain moist on it is how dark stains are achieved. It is best to leave henna on for a minimum of 3 hours in order to get a good stain. The best stains are produced when henna can be wrapped and left for 6 hours or more and even overnight. Wrapping traps the heat from your skin and makes it sweat. This in turn rewets and reheats the henna from underneath. Just like the plant, the henna paste thrives on heat. The hotter your skin is the better stain you will achieve.
After the henna is left on for the desired amount of time the dry henna is scraped off the skin & some type of oil such as olive oil or cocoa butter is applied to the design. The stained area is not exposed to water for at 4-24 hours after paste removal. This allows the henna stain time to "cure" (or oxidize since it is now exposed to air) and for the lawsone dye to soak further into the skin and begin the darkening process. Henna should never be scraped off with water or exposed to water in this time period. The chlorine and chemicals in water will weaken the stain causing it to not get as dark or last as long. Once the time period is past then the stain can be exposed to water. Like any stain it will begin to fade away in time. In order to keep your design dark and on as long as possible you can waterproof it with petroleum jelly, waterproof sunscreen or any heavy duty moisturizer when showering or bathing.
Dark/Light stains on the Body
If you have ever had henna done on different parts of the body or seen a finished photo where some areas are light and some are dark. Why does this happen? Essentially the thicker and courser your skin is the more layers the lawsone dye has to soak down into. The thinner the skin the less layers it has to soak into. Therefore the dye will merely sit on the uppermost layers and will fade away much faster. For example, the best places to get a dark stain is your palms, knuckle areas, sides and bottoms of the feet. The are places of the skin that come into contact with surfaces daily or exposed to the elements. Areas such as the face, chest, back, legs and upper arms will stain but not no where near the darkness as with thick skin.
Another factor to consider is your body chemistry. Folks who have a high alkalinity level will achieve dark stain as alkalies will oxidize the stain to become darker. Then again there are some folks who's skin just don't take the lawsone dye very well if at all. Below is a link to the Henna Stain chart created by Catherine-Cartwright Jones that shows the different parts of the body and how well they stain.
http://www.hennapage.com/henna/encyclopedia/skin/skinzones/bodstain1.html
Black Henna
To start off HENNA IS NOT BLACK. In powder form henna can be a bright green to a dull greenish brown. When mixed with liquid such as tea or lemon/lime juice and essential oils or "terps" then powder then becomes a paste that eventually turns into a greenish brown mix. This is the natural coloring of henna. Henna can never be made naturally black and natural henna needs to be on a minimum of 4 hours, not a half hour.
http://www.hennapage.com/henna/ppd/tradsafe.html
Black henna is created when black hair dye/sometimes brown hair dye is mixed with the henna powder. This in turn will create a black/brown stain on the skin with in half an hour after applying. Sounds great and much faster then regular henna huh? Not when you discover that a few days to even a couple of weeks later you have redness, itchiness, blistering and scarring from where the tattoo was. You may swell up or end up in the hospital with hives, enlarged limbs and all sorts of nasties. Now why did this happen? You got snaked into having PPD henna on your skin. PPD henna is henna mixed with hair dye and it is the chemical para-phenylenediamine that these reactions. Most of PPD henna is illegal (or at least in Canada it is and needs to be illegal here) Hair dye should never be put on the skin since it is not FDA approved for skin, only hair. Booths who tout black henna tattoos need to avoided at all costs. You most commonly see these in foreign countries or beach/resort tourist areas.
One of the worst things about getting PPD henna tattoo done is once you have a reaction to it you are permanently sensitized or allergic to any product containing para-phenylenediamine or any of it forms. PPD is also a known carcinogenic and trans-dermal toxin that permeates your skin. It then travels through your blood stream and to vital organs. For example click on the links below to see/read stories of what has happened to those who have had it done.
http://www.hennapage.com/henna/ppd/ppdburngallery.html
http://www.hennapage.com/ppd/wilson.html
http://www.hennaforhair.com/ppd/ppdreaction/
SO PLEASE, PLEASE IF SEE ANY BOOTHS TOUTING BLACK HENNA TATTOOS AVOID AT ALL COST (and warn people along the way while you are at it.) Or if you do see ask what the henna is mixed with to produce the black stain. If they chose not to disclose this I suggest you book it away from there. All ethical henna artists will be happy to tell you what is their henna mix if they don't already have a sign up stating it. We will also babble non-stop about henna to educate folks then we go our rant and rave about black henna. The best thing you can do is educate yourself. Listed below is the main link to Henna Page for more information on black henna and what to do if you are a "victim" of it a.
Also many doctors are not aware of the effects of Black Henna. If you are going to a doctor for reactions due to black henna my advice is print these articles and take with to make sure he understands just what he is dealing with.
http://www.hennapage.com/henna/ppd/index.html
See Canada's health ruling on PPD henna
http://www.hc-sc.gc.ca/ahc-asc/media/advisories-avis/2003/2003_66_e.html
Henna allergies and medical conditions
Is henna safe to put on the body? Absolutely provided it has not been mixed with hair dye. However there are
some who may be sensitive to the henna plant itself or any of the ingredients used. Fortunately to this day I have not had one client who has had an allergic reaction. Depending on the oils used in "terp" the henna your skin may have a slight tingling sensation. Some of the essential oils that are used such as tea tree or clove bud can cause this. Some folks skin will be more sensitive to the oils used than others. If this does happen don't panic as I am also an aromatherapist (I have had this happen with certain oils on my skin). It is perfectly natural for your skin to do this however if it gets to annoying wash the henna off well with soap and water. You can always ask the artist if she/he could make henna paste without the oils if you want to have the artist do henna on you at a later time. A good educated henna artist will understand and be happy to oblige. Another way to tell if you might be allergic is have the artist do a patch test on your skin. If nothing happens over the 24 hours you probably are not allergic.
HOWEVER, if you have been diagnosed with a blood disease called Glucose-6-phosphate dehydrogenase deficiency or G6PD. Basically the lawsone dye causes bilirubin levels to rise and the person can go into anemic shock. Most affected by this are newborns. Newborns who have this deficiency should never be hennaed. Their organs and skin are very permeable and fragile and henna will cause haemolysis of their blood cells.
Adults who have this disease are also safe to avoid henna as well. If you are a G6PD deficient but in very good health it is considered safe to have very small amounts of henna done. However if your are anemic with this deficiency it is best to avoid it all together. For further information on G6PD adults and newborns this please click on the link below.
http://www.hennapage.com/henna/encyclopedia/medical/neonatal.html
http://www.hennapage.com/henna/encyclopedia/medical/g6pd.html
http://www.hennapage.com/henna/encyclopedia/medical/
