Is it really the colour of love ?
Having grown up in a region which sees hot and dry summers (Ideal for Henna’s color), I used real henna leaves (both fresh and dried in shade) many times but could never get the dark brown stains shown in ads or from readymade powder. Even mixing catechu/Eucalyptus oil/clove oil/sugar/ladyfinger-juice could not give that shade. One who has used henna leaves will know that the natural color of henna is darkest orange rather dark brown black.
Henna plant which grows in semi-arid zones produces maximum dark pigment in temperatures between 35 and 45 °C. It gets destroyed when soil is moist or temperature is less. More than 90% of Henna used for body art comes from the dry Rajasthan being a cash crop where nothing grows. Being of best quality, 90% of the produce is exported (what’s left for us). When henna leaves from such hot climate henna give dark orange color where does this black-brown comes from? When dried in shade leaves become darker and the color of powder is very different from the shiny green sold in the market.Henna leaves grinded at home gave a fantastic shine and softness to hair which I could never get again once I moved out of my hometown.
Now I find so many queries and tips about the usage of Henna for hair and how to avoid hair becoming brittle after application. People write different blogs for their trials of various ingredients of hair pack. But one’s labour is not repaid and people are taking the convenient way of opening the bottle of chemical laden hair colours and packs. Why that is even after knowing about harmful chemicals and carcinogens people are preferring ready-made colors. One would say convenience but the real reason is that even after so much trouble effects are worse than packed stuff. Itchy scalp and dry brittle hair are common side-effects of powder henna in all the brands. There are other not so obviously related effects like eye irritation, asthma, sudden acne and so on.
Every year, just after Karva Chauth, hundreds of women line up at dermatologists’ clinics with red and swollen hands. According to Dr. Thami of GMCH-32 , with the increase in chemical content in henna, the number of women complaining of skin allergies increases every year at the dermatologists’ clinics .
What’s different then?
Difference lies in maintaining the supply inside the country and at the same time not letting the export get out of hand or simply adulteration. Wide variety of additives are found in Henna. From ancient times color enhancers are added to Henna. These were parts of other plants like dried Amla,Haritaki (Myrobalans), Manjit (Madder root), Ratanjot (Alkanet- root) or Katha(Catechu) having tannins. These dye plants give a redder henna color, and are harmless but none of them give a black-brown color to henna. On rare occasions some people have allergic reactions to these as with any herb. Now a days these herbs are expensive adulterants and cheaper ones are preferred.
Henna becomes harmful when harsh chemicals and minerals are added to it for aesthetics, dark color, to decrease the time of staining and to make up the bulk.
A study in 1989 for the Department of Marketing and Inspection, Central Agmark Laboratory shows all samples of henna powder mixed with dyed fine sand. Dyes used were auramine yellow (C.I. No. 41000) and diamond green (C.I. No. 20440). This is known as polishing the henna locally. This is to make it more eye appealing.
Unlike Lawsone, the natural color of henna, these added synthetic azo-dyes used for dyeing the sand or for polishing the leaves may have an adverse effect on the skin. Recommendations were that 99% of the powder should pass through a 500 micron I.S. sieve to see if there w were any dyed sand particles in it.
Based on this study an independent microscopic analysis of Henna samples was conducted in Kent, Ohio (2004)and presence of chunky green dye particles was confirmed in all the samples along with other plant based additives.
Its been years after these studies and ways of adulteration too have changed. With advanced dye technology I don’t think its difficult to mix dyes to give the required stain.
The Worst- “Black Henna”
Some times a dangerous hair dye is mixed with henna to darken the stain. Many a times it can be used alone as ‘Black Henna’ (for temporary tattoos) . ‘Black henna’ contains para-phenylenediamine oxidative dye, a highly sensitizing chemical which produces delayed hypersensitivity reactions on the skin. ‘Black henna’ body art evolved from traditional henna body art when artists began to add para-phenylenediamine to traditional henna body art because the chemical dye produced a faster, more efficient, darker stain. This chemical addition causes blistering, scarring in the area of the pattern, with a reaction appearing as late as five to twenty days after application . According to Dr Thami “Arabian henna is very dangerous. It is full of harmful chemicals and can cause a lot of trouble. However, herbal henna is good, but most of the time black hair dye is mixed in it in order to darken it, which is very harmful.” 
What to do?
There are no alternatives for the traditional body art. If possible getting all herbs and leaves to make one own concoction is the best option. Strict rules for adulteration should be in place .
For hair applications there are alternative herbal remedies, packs to darken and condition the hair without using powdered Henna. One such solution will be coming shortly on this portal. Till then stay safe.
“Study of Quality Characteristics of Henna”, Chourasia, Sardar, Patil, Mathew,Kanpur, India: Essential Oil Association of India, 1989