Egyptian henna and mixtures made from plants and insects were the first haircolors. Natural ingredients, limited as they were, remained the essence of haircolor until the 19th century. In Europe and Asia Henna and Indigo combination was used to give hair light brown to black shade. Chamomile flower extracts were used to lighten hair. These ingredients are still used in herbal hair dyes and also as home recipes.
Why should I be aware of this?
Some scientists believe that the risks of adverse effects of chemical hair dyes are real enough. Manufacturers have called their findings flawed and vouch for the safety of their products. Several studies have been carried out on hair-dye use and cancer risk. But there does not appear to be an educated decision on whether any risk exists, or what is the extent of that risk. With manufacturers changing the ingredients in their products faster than scientists can test their safety, it's unclear if we will ever really know what we are up against.
One not only has to make a choice of colors but even product selection requires sifting through mass of ingredients and chemicals contained in different brands to zero in on the one that is least harmful and suits the particular hair condition. What is important is not only the look of your hair but also its health.
How safe are the chemicals used in the dyes? How effective are natural dyes? Is the word "natural" on a package of hair coloring product enough to allay our fears?
How does this affect me?
Fears of Harmful Effects -- Historically consumers are known to be allergic to a wide range of chemicals in beauty products, with the biggest threats coming from hair colors. There are conflicting views on the harmful effects of hair dyes. The cosmetics industry claims hair dyes are safe, while environmental groups feel they are risky.
Safety regulations for hair dye chemicals have always been of highest concern. Hair dyes have, therefore, been the most studied and regulated market among consumer products. Yet fears of cancer risks and allergy remain and this brings hair dye repeatedly under scrutiny. Health hazards associated with hair colour are:
- Dermatitis of the eyes, ears, scalp and face.
- Swelling of the scalp likely to occur
- Burning sensation in the scalp
- Other allergies are possible in some cases
Numerous epidemiologic studies have shown there is no risk of cancer from chemicals used in hair dye. Regarding allergies too, the studies have allayed fears as instances of hair dye related allergies occur at a rate of one per one million products sold.
Allergy warning labels are put on oxidative hair dye products to make consumers aware of potential allergy risks. Most products recommend skin sensitivity tests before coloring hair. See Decoding Personal Care Labels
Hair Colour Allergies -- Many people are said to be allergic to a wide range of ingredients used in hair dyes, with the leading cause related to p-Phenylenediamine (PPD). Ammonia, peroxide or diaminobenzene are also known to cause allergic reactions. Hair colors that use mercury, lead or other metals are far more damaging.
Aniline dyes, which are often used in semi-permanent hair dyes, are said to be toxic and cause irritation to the eyes, skin and mucous membranes to hypersensitive people.
Reactions from PPD -- Allergic reactions from PPD are known to cause facial and neck swelling. Inhalation is likely to bring about coughing, sneezing and shortness of breath, and respiratory problems in extreme cases. Skin contact with PPD may cause rashes and eye contact irritation, redness and pain. These problems, however, do not mean that you should never color your hair. These are only tradeoffs for looking gorgeous. Just like we do not give up eating our favorite foods because they may contain toxic implications.
Hair Dye and Pregnancy -- There is no conclusive study to prove that dyeing one’s hair has any effect on pregnancy. In some animal studies, however, no significant change was noticed. Low levels of chemicals in the dye get absorbed in the skin. The danger could be in the inhalation of the fumes, which, though not harmful to the baby, can make you nauseous.
It is advisable to take precaution like consulting a doctor before dying and selecting a well ventilated area for dying. Wear protective gloves if your are dyeing your hair yourself. Absorption of fumes can be reduced by rinsing your scalp with cold water. See How to Dye Your Hair While Pregnant.
Research on Hair Colour
- One study of nearly 897 people found that women who used permanent hair dye at least once a month were twice as likely as women who did not use permanent hair dye to develop bladder cancer. 
- A panel of the International Agency for Research on Cancer (IARC) in Lyon, France reviewed the evidence and found a consistent risk of bladder cancer in male hairdressers and barbers. 
- A second review of the evidence on personal hair dye use found some studies suggested a possible association with bladder cancer, lymphoma, and leukemia. 
- The Environmental Working Group has ranked 456 hair colors in their Skin Deep cosmetics database, and roughly 400 of them are considered high hazard because they contain toxins linked to
- Developmentive and reproductive toxicity
- Immunotoxicity and organ toxicity
- Allergies and irritation of the eyes, skin or lungs.
- A separate study also found that women who use hair dyes for more than 20 years may nearly double their risk of developing rheumatoid arthritis. 
Hair color controversies
Most hair colorings made from coal tar are exempted from the Food and Drug Administration's (FDA) safety removal provisions of the Food, Drug, and Cosmetic Act of 1938. Unlike other products, they only have to carry warning on their labels.
In 1978, the FDA proposed a warning on the labels of hair dyes containing 4-methoxy-m-phenylenediamine (4MMPD) or 4-methoxy-m-phenylenediamine sulfate (4MMPD sulfate), two coal-tar ingredients. This followed findings by researchers at the National Cancer Institute — based on feeding lab mice large amounts of the substances — that the compounds were carcinogenic.
Although ingesting large amounts of carcinogenic compounds is a far cry from the amounts absorbed through the skin, hair dye manufacturers withdrew the substances from their products. But they substituted compounds with similar chemical structures. Since then a wide variety of studies have argued back and forth about the danger posed by the permanent dyes.
All about hair color
Coloring should be done in accordance with the condition and the texture of one’s hair. Like those who have badly damaged or dry hair should first go in for intensive hair conditioning treatment before coloring. Coloring options should be based on ones individual requirements and hair conditions.
Types of Colors
- Temporary hair colors -- These are applied in the manner of rinses, gels, mousses, and sprays on the surface of the hair and can be washed out when needed. Temporary hair coloring is an acid-based formula that pits a coating on the strands of the hair and does not penetrate the skull. It is ideal when your requirement for coloring is only for a particular occasion.
- Semi-permanent dyes -- These colors enter the shaft of the hair but don’t remain permanently. They can be washed away by using shampoo 5 to 10 times.
- Permanent hair dyes -- Can’t be washed out as they penetrate deeply into the hair shafts. Permanent hair coloring uses a mild developer and the hair can retain its color for a few months.
- Cheap hair dyes -- Cheap hair dyes have metallic salt. These have the most damaging impact on the hair. Once it is done it is very difficult to do any other chemical services on it successfully. Such chemicals damage the integrity of the hair.
- There are many organic hair dyes which have natural plant colorants and conditioning ingredients, such as certified organically grown henna, walnut shells and buckthorn bark.
The majority of dyes sold are the permanent two-part dyes that can last up to six weeks. There are two separately packed components in permanent hair colors which have to be mixed before application. One is hydrogen peroxide (usually 6%) in water or a lotion base and the other an ammonia solution of dye intermediates and preformed dyes. On application, the hair swells with the effect of ammonia, enabling the dye precursors to penetrate the cuticle. It takes half an hour for the color to develop. With higher concentration of intermediaries darker shades can be obtained.
Melanin proteins found in the hair are: eumelanin, which creates hair shades from black to brown, and phaeomelanin, which provides red and yellow-ish colors. Hair turns white or grey due to absence of pigments.
Hair Dye for Men -- Today men’s hair dye has come a long way since only black was used to cover grey or pink or green used by gay rockers. Now men too have the option of using frosty red or gold used by stylish women of the day. Now there are brands men can relate to. With men caring more and more about their looks, men’s hair dye could not be far behind.
Here are some tips for people who use hair colour.
- Steer clear of the darkest shades. Although all of the shades use essentially the same chemicals, there's quite a lot more of them in dark brown and black shades than there are in blonde, red or lighter shades.
- Avoid permanent hair color, as they’re the most toxic. Semi-permanent and temporary colors are less so.
- Look for natural brands of hair color that use henna, herbal dyes and vegetable dyes as primary ingredients. These are likely to be much less toxic than the average hair color.
- If you go to a salon, choose one that is chemical-free, odor-free, herbal or caters to people with multiple chemical sensitivity and allergies. These salons tend to use less toxic products.
- Ammonia and PPD content in the dye should not exceed 4%.
- If you are a woman under 40 and have premature greying, it might be a result of hypothyroidism.
- Check with manufacturer -- Even if you have a list of harmful and banned chemcals, it is often impossible to know if your chosen hair dye contains them or not. Because many such ingredients appear as code numbers on the packaging, or other names are used. It is advisable to find out from the manufacturers what exactly they contain and how they can be harmful for your type of hair.
Precautions to follow using hair color
- Always do a patch test.
- Be patient and follow the instructions.
- Never use leftover colour as it can get oxidised and spoilt. Throw away whatever is left.
- Colour your hair the day after you wash it. This way your hair gets protected by natural oils that cover the hair.
- Do not blow dry the hair.
- Identify signs of an allergy-itching or burning of scalp. Immediately wash off the colour, take an anti-allergy tablet or consult a doctor.
- If you are getting your hair coloured for the first time, get it done at a good salon by a trained person. After that, get every 4th colour application done professionally.
Caring for Coloured Hair
- Use shampoos meant for coloured hair and always use a conditioner. Hair colour interferes with natural conditioning. If your hair gets too limp after conditioning, use a leave-on conditioner or hair serum after a wash.
- Go in for either hot olive oil or hot almond oil massage every 15 days. This means tying a hot towel for at least 10 minutes after the oil application.
- Keep a gap of 4 to 6 weeks between two colour applications.
- Apply hair oil before going for a swim. This will prevent further damage from chlorine in the pool water.
For hair coloring to be effective permanent hair dyes must contain both color and a developer. The developer lifts the outer opening of the hair known as cuticle, enabling the color to penetrate. These developers contain chemicals in the form of ammonia and hydrogen peroxide, which also cause allergic reactions.
These chemicals are contained in varying concentrations in most permanent hair dyes. You choice of brand will depend on what composition is best suited to your hair and skin conditions. Chemicals in hair dye cause a degree of damage but it is considerably mild if you are darkening your hair. If you are a regular at dying your hair, you may not notice it.
But women with problems of hair loss or certain scalp disorders should be extra careful in checking the chemicals which may not suit them
Ammonia-free products -- All the more expensive hair color brands, such as Loreal, Revlon, Garnier or Sunsilk, Pantene and many others, are ammonia-free. Though ammonia is bad for your hair, colors with ammonia generally last longer than those without it. Ammonia can make some colors extremely conditioning depending on the other ingredients present in the color, like natural oils.
Though exposure to high levels of ammonia can cause irritation, in small concentrations it is not toxic to the body. If you are not allergic to ammonia, you may go for brands with low ammonia content which can be found in most brands as it is necessary for some colors to cover gray or lighten the hair.
Many colors may lead you to believe they contain natural dyes when in fact they may contain both natural ingredients and synthetic chemicals.
Ecocolors contains small amounts of ammonia and peroxide. It has a soy and flax base and uses rosemary extract to condition the hair and flower essences instead of artificial scents. Herbatint is an ammonia-free dye, but uses low concentrations of p-Phenylenediamine and peroxide.
p-Phenylenediamine -- Everybody's hair is different - what works for one might not work for the other. For effecting a dramatic color change it is difficult to avoid questionable chemicals. p-Phenylenediamine (PPD), found in many permanent hair colors, is one such chemical. In order to be effective even green-friendly permanent hair dyes too require some chemicals such as ammonia, peroxide, p-Phenylenediamine or diaminobenzene=AD.
Hydrogen Peroxide -- For some hair conditions hydrogen peroxide is the main culprit. If you want a lighter hair or change the color of your hair completely you require bleaching. Hydrogen peroxide bleaches your hair and thus damages it. But the extent of the damage will depend on its level of concentration. Some of L’oreal semi permanent hair dyes do not have ammonia but contain hydrogen peroxide. But because it is not a permanent color, it contains very small concentration which does not harm.
If you only want to cover grey hair or premature greying you don’t need a product with hydrogen peroxide in it. All the three chemicals, ammonia, p-Phenylenediamine and hydrogen peroxide are harmful for women with hair loss problems and scalp dermatitis.
Monoethanolamine -- Monoethanolamine does not cover gray as well as ammonia and cannot lighten the hair as much as ammonia can. Monoethanolamine color works well if your hair is porous. It however, fades quickly.
Hair colour and hair dye
Hair colour and hair dye are often used in the same breath, but chemically they are different. Hair dyes contain heavy metals that can be harmful. They cover the hair on the surface so get washed off faster. Most of them are shampoo-based. On the other hand, hair colours are permanent in nature. They contain the chemical paraphenylene diamine (PPD) which enters the hair shaft and colours from inside. This colour does not fade and only the root needs to be touched up as new hair emerges.
- Women who started dyeing their hair at the age of 20 are twice at risk as against women who started dyeing their hair at the age of 40.
- Permanent and semi-permanent hair colors increase risk to cancer, especially breast cancer.
- Tests on animals and humans show that during the 30 minutes the hair color is applied on the scalp, it is rapidly absorbed by the human body. 
- The global hair dye market is now valued at approximately $7.2 billion.
- There are over 70 different blond shades available in the Clairol range of hair colors.
- As against 7 percent of American women coloring their hair in the 1950s, 75 percent color their hair in 2000s.
- In Asia, where, across the continent, everyone’s hair has near-same natural color, about 60 percent of the women in Japan and Korea color their hair.
- About 30 to 40 percent of the women color their hair in Singapore, Taiwan and Hong Kong and less than 20 percent do so in Malaysia, Indonesia, China and Vietnam.
- The first safe hair dye was created in 1907 by French chemist Eugène Schueller.
- Hair color ingredients
- Natural hair color
- Herbal hair color
- Hair conditioner
- Ingredients of hair conditioner
- Homemade hair conditioners
- Grey hair
- Premature greying
- Ingredients of shampoo
- Hair color business to dye for as sales picture keeps brightening
- Can I color my hair while I am pregnant?
- Hair Coloring
- Non-Toxic Hair Color Facts
- Finding the Right Hair Color for You
- A Homemade Hair Dye May Be the Answer!
- Non-Toxic Hair Color Facts
- Can Hair Dyes Give You Cancer?
- Is Hair Colour Worth Dying For?
- How to pick the right hair colour
- How safe are hair dyes and colours?
- A colourful review
- ↑ Are dye jobs to die for? USA Today
- ↑ Hair dyes found to increase cancer risk
- ↑ 
- ↑ 4.0 4.1 4.2 
- Refer to Henna and Indigo Application to know more about the ingredients used in herbal What Are the Ingredients in Hair Color?
- For details of applying home-made hair colours, visit Covering Gray Hair Recipe.
- To learn more about colouring your hair during pregnancy, see How to Dye Your Hair While Pregnant.
- Refer to Home Color Advice for colouring hair at home.
- For details of various hair colours refer to Haircolor Basics: Hair Pigment Categories.