The Science of Henna and Hair

Why your hair feels trashed and brittle after using synthetic dyes

What is Henna?

Reference Library

Exactly how does henna 'work'? The Chemistry of Henna.

How do manufacturers of "henna hair dye" make all those different henna colors?

Boxes of commercially produced “henna for hair” come in a range of colors. 

Henna, itself, DOES NOT come in a range of colors.  

The only dye molecule in henna (Lawsonia Inermis) in sufficient quantity to stain hair is Lawsone , which is a red-orange molecule.  Any company that claims they create the wide range of henna colors with 100% henna,  using roots, bark, or other parts of the henna plant to achieve their colors is …… lying or seriously ignorant. Only henna leaves are useful for dying hair, and other parts of the henna plant do not dye hair other colors.  Chemicals, metallic salts or other plants must be added to henna to make any color other than red. 

These pre-mixed colors  are compound hennas.   If you buy a box labeled henna that claims to dye hair blonde, brown or black, there is something other than henna in that box.
 

Compound Henna Dye

This is a term that refers to hair dye marketed as henna,  and is formulated in different colors. 

These mixtures may contain additional plant dyes, may contain  metallic salts, and may contain para-phenylenedmine. 

Compond henna may damage your hair.  

Pure body art quality henna is good for your hair.

There is no such plant as "blonde henna", "brown henna" or "black henna". The plant, henna, lawsonia inermis, has only one dye molecule, and that molecule is red-orange.  

Chemicals, metallic salts or other dye plants must be added to henna to make any color other than red.  These mixes are termed compound hennas.  

Some dye plants can be added to alter the color of henna.  Some chemicals can be added to alter the color of henna.

Metallic salts alter and fix a dye stain. Many “henna colors” are created with metallic salts.  The most frequently used material is lead acetate, though silver nitrate, copper, nickel, cobalt, bismuth and iron salts have also been used.

Dyes with lead acetate gradually deposit a mixture of lead sulfide and lead oxide on the hair shaft.  

When you hear that henna has “metal”, “lead”, or “coats the hair” and “leaves it brittle”, that refers to a compound henna dye, full of these metallic salts. 

Hair bleach, permanent hair color, and permanent wave solution are a disastrous combination with compound (metallic salt) henna dyes. These can result in green, purple, or totally fried hair. 

Some pre-mixed hennas have para-phenylenediamine.  Some pre-mixed hennas have very little henna whatsoever. 

Body art quality henna does NOT have metals, lead, nor does it “coat the hair”.  This website is dedicated to providing you with the information to learn to dye your hair with 100% pure henna, indigo, cassia and amla without using pre-mixed "compound henna".  This is very much like learning to do your own cooking instead of eating processed food.  You'll know what you're getting and you'll know what its doing.  The pre-mixed "compound henna" products may not have an accurate or complete ingredient declaration.   If you cannot be certain what is in each box, you cannot be certain what cross reactions may occur between your compound henna and preceeding or subsequent chemical process, and you won't know if you're going to have an allergic reaction to something in that mixture.   

How can you find out if the henna hair dye you've been using has toxic metallic salts? 

Harvest some of your hair. 

Mix one ounce (30 ml) of 20-volume peroxide and 20 drops of 28% ammonia. 
Put your harvested hair in the peroxide-ammonia mix (this is in synthetic hair dye).

If there's lead in the henna you've used, your hair will change color immediately.

If there's silver nitrate in the henna you've been using, there will be no change in hair color, because silver is coating the hair. However, silver nitrate leaves a greenish cast to your hair, so you can tell by that. 

If there's copper in the henna you've used, your hair will start to boil, the hair will be hot and smell horrible, and the hair will disintegrate.

With all that crap, frequently unlisted, in some henna products, no wonder henna's gotten a bad rap!

Why do some boxes of "colored henna" have no declaration of ingredients?

Some countries where these products are initially manufactured do not have laws requiring the declaration of ingredients in cosmetics. So, they can put anything they want in that box and they don't have to tell you what's in it.  If someone in the USA imports these mixes, they are not required by law to go back and discover what's in the bulk mix that was passed through customs marked as "henna", and they don't have to declare it on their package.  This is how a company can have a dozen "colors of henna" from blonde to black, and sell them without listing their ingredients .. and they usually do. The person selling the product may have no idea what's in the box, or they may know and not want to tell you.   If its a box of hair dye that claims to be henna and it claims to dye hair something other than red, and the powder inside is not green ... it is NOT HENNA.  Many products labeled "herbal henna" actually contain para-phenylenediamine.  If you're allergic to chemical hair dye and you use "herbal henna" you may to have an allergic reaction to the chemicals in it.  The claim of "no ammonia, no peroxide, all natural" does not mean you're getting safe, pure henna.


You can add other plant dyes to henna to create hair dye colors: 

Mixtures with other plant dyes with henna, to create other dye colors, are called “henna rangs”. 

Indigo, Indigofera tinctoria

Is a plant that produces a dark violet blue dye, which we are familiar with as the color used to dye blue jeans.  Indigo can be used with henna to dye cloth and hair from brown to pure black, depending on the proportions of henna and indigo.  Though you can use indigo to dye skin blue, you cannot dye skin black with indigo. 

Woad, Isatis tinctoria

Woad is a plant that had a blue dye, and it is also used to dye hair.  It is more dye fast in hair than indigo, but it does not create the vivid blue-black.  You can use woad to dye skin blue, but you also cannot dye skin black with woad. 

Walnut, Juglans regia

The leaves, or green walnut shells from walnuts can be combined with henna to create brown hair dye.  Walnut dye is juglone, 5-hydroxy-1.4-napthoquinone.  This is a larger molecule than henna.  It is not a long-lasting dye in hair, so is usually used with henna.  . Many people are allergic to walnut!  Walnut is often mixed into henna powder for skin.  It makes a very fast dark stain, but it does not penetrate as deeply as henna, and is far more likely to cause skin irritation or an allergic reaction. 

Cassia obovata

Many “neutral henna” products are actually cassia obovata.  There is no henna that is “neutral” just as there is no henna that is “black.  Its dyes are anthraquinones, and also has flavonoids and resins”  Cassua dyes a blonde-gold color, and “thickens” hair. 

Want to know more? http://www.botanical.com/botanical/mgmh/s/senna-42.html  

Catechu,  Ourouparia gambir and Acacia catechu

Catechu is from two different species, Ourouparia gambir  and Acacia Catechu.   Ourouparia gambir makes a yellow dye, and Acacia catechu makes a dark brown dye.  These are tannin dyes.  Extracted tannins from these dye plants are added to henna to create other various shades of henna, blondes, browns, and dark browns.

Want to know more? http://www.ibiblio.org/herbmed/eclectic/sayre/acacia-cate.html  

Saffron, also called Sadr, Crocus sativus L.

Saffron is used to create blonde hair dye

Want to know more? http://www.iran-export.com/exporter/company/sadr/products.htm
and http://www.hort.purdue.edu/newcrop/med-aro/factsheets/SAFFRON.html  

Chamomile, Anthemis nobilis

is used to create blonde dye colors, but is not very effective or permanent.
Want to know more?  http://www.botanical.com/botanical/mgmh/c/chammo49.html#com

Rhubarb Root, Rheum rhapoticum

   

Some henna hair dye sellers have a range of henna colors 

Others claim all the "colors" to be 100% pure henna, and that is simply botanically impossible. 

The plant based "henna colors" are generally something like this: 

This is the list of ingredients used by Henara, a henna hair dye company that produced various “henna colors”.  Their ingredients were published in “Henique” trade publications, and are typical of commercial all-plant henna mixes.  Of course, you can also mix these yourself!

Natural red:  henna
Brown: henna and woad
Golden: henna and sadr (saffron)
Chestnut brown: henna and woad
Dark warm brown henna: karchak and vashma
Black henna:  karchak, vashma and indigo

So, if you've been wondering how the manufacturers are coming up with "henna colors" ... that's one way its done. 

However ..... 

Other “henna hair dye” products are on the market, with  little or no henna.

The refined, concentrated chemicals in these products may stain hair more quickly than traditional henna mixes.  In 1980's the following were marketed with ingredients similar to products currently on the market.  These products often have "henna"  and "natural" on the front of the box, when there's little of either within the box. 

Meta Henna International marketed seven “henna colors” from blonde to black.  They used henna extract to create a fast brilliant color, then added other dye plant extracts to propylene glycol. This made a concentrated, fast acting, premixed color base. 

Autumn Glo had a henna hair product line also was based on henna extract, with added Lawsone. 

Hennalights were color intensifying shampoos with henna extract.  Their blonde had chamomile, and their brunette was henna.  Both had hydrolyzed animal protein in a shampoo base. 

These may not be harmful in themselves, but they certainly add to the confusion about henna, because their labeling implies that they are made of natural henna.
 

Want the good stuff without all the yuk? 
Buy body art quality henna and mix it yourself!



References: 

American College of Cosmetology
Standard Textbook of Cosmetology
Raritan, New Jersey, 1981

Amro, Bassam Izzidin
Dyeing with Henna and Related Materials
thesis for PhD at the University of Wales, 1989

Dalton, J.
The Professional Cosmetologist
West Publishing Company, 1976

Kenny, D:
Commercial premixed henna color treatments and conditioners, 
Cosmetics and Toiletries, 95 (6) 43, 1980 

Spanoudi,  S. P;
Henna, its morphology, chemistry, and hair dyeing properties
M.Sc Theses, UWIST, 1983

Wall, F.E.
Hair colorings, Bleaches, Dye removers
Chapter 23 in Cosmetic Science and Technology
2nd Edition, Vol. 2, Wiley Interscience, 1972