What is a Dye?
Dyes are complex Chemical compounds with several unsaturated / double bonds in its chemical structure. Colour is due to the multiplicity of double bonds. Unsaturation makes a product reactive / unstable.
Hair Dyes are normally Coal Tar dyes. They are Toxic / a bit poisonous. Toxicity details will either be in the outer carton of the hair dye or in the small product leaflet that may be inside the carton. Read them carefully before using a product.
What is a double bond?
Simplified, Organic Chemistry is the chemistry of Carbon compounds. Many Dyes, Pigments, Pharmaceuticals and Vegetable Oils are generally Organic compounds. There can be carbon chains, with one carbon atom linked to another. In vegetable oils / fatty acid chain, there are 12 to 20 carbon atoms in a chain - long chain fatty acids
Unsaturation: A Carbon atom in a compound may share two electrons with its adjacent Carbon or another atom to complete its orbital structure. This is called double bond / unsaturation. To simplify, double bond means forced, easily breakable alliance. It is like, say 3 persons sharing a normal 2 seater bench. The double bonds make the compound reactive. Ethylene is an unsaturated compound. It polymerises to make Polyethylene.
In saturated compounds, the sharing will be limited to a single electron by a carbon atom. Hence such saturated compounds will be less reactive / bovine. Coconut Oil, mineral oil, methane are examples for a fully saturated compound.
The dyeing process
a] Hair has to bleached to lighten the existing colour of the hair. It is Ammonia or Peroxide bleach - chemical bleach. It is an assumption that everything would work safely in the way we wish
b] The dye has to colour the hair Chemically
c] It has to stick to the hair for 2 to 4 months
"Free Radical" means an unpaired or a single, free Electron. It is an unstable, hyperactive agent. This can damage the DNA, the nucleus of the Cell, the building block of the Body.
Lot of Free Radicals float about the Scalp. UV light in Sunlight triggers the Free Radicals reactions. These are uncontrollable factors. And the Dye is a highly unsaturated compound. So, in the long run, it can be the catalyst for undesirable / unwanted chemical reactions that can damage the hair.
With uncontrollable Free Radicals over the top of the scalp and toxic unsaturated compounds on the hair, it is an open invitation for a chain of chemical reactions on the top / hair. The extent of damage can vary from one to another.
Long Chain ceramides can minimise the Free Radicals reactions. These are present naturally in the root area. But these can get knocked out a bit due to bleaching.
Other Risk factors
- All hair dyes are normally toxic / poisonous
- They irritate the skin. Itching is common. Hair is a protrusion from the skin. If the skin is affected, hair would also suffer. These chemicals can perhaps seep into the skin [this is just a guess from hearsay of long term side reactions: not verified with books]
- The Bleaching and other intended Chemical reactions can loosen the chemical bonding in the hair.
- Dyes only change the colour and nothing more is not a research backed assumption.
You can learn about the damages from a long term dye user. [I do not have detailed personal knowledge]
Dyes have to be used for life. It is costly and tedious to apply. The hair may loose its natural appearance. A gray hair will not look a natural grey but an odd looking pale yellowish white. The hair will look lumpy and would scare a small child. The black colour would also look odd. It does not matter whether the dye was made in India or in New York, Paris or London. Listen to an old user and then decide your course.
Kali Mahendi / Henna
Mahendi / Henna can stick to the skin. It gives out a Reddish orange Colour. That is why Indian ladies use it on Auspicious occasions like Marriages.
That basic colour cannot turn into Black on the head simply because we applied it. Kali Mahendi is a deliberate distortion as it is a Botanical impossiblity
It is a personal decision – graceful greying or artificial colouring.