The Hairy Facts
Types of Hair Dyes
Plant-based Hair Dyes
Diseases implicated from Hair Dyes
Types of Hair Dyes
Permanent Hair Colour (Level 3):
Used to match, lighten and/or cover grey hair. Chemical process changes
the colour of the hair from the inside out as both a developer/oxidizing
agent and an alkalizing ingredient, like ammonia and peroxide (or both),
roughen and break down the hair cuticles so they can deposit dye into the
hair shaft. This permanent change in the structure of the hair lasts until
the hair grows out. Hair lightening refers to "bleaching" or "decolourizing"
and is a permanent chemical process involving the diffusion of the natural
colour pigment or artificial colour from the hair.
Hair dyes are very reactive and the ingredients used along with them can
be quite harsh. Care must be taken when using them on your own. The allergic
reaction that comes from hair dye is generally one of sensitization to p-phentlenediamine
(PPD). The reaction will most likely occur each time a person dyes their
hair and will probably get worse each time
Key chemicals in permanent hair dyes:
· Ammonia - used as an pH adjuster/alkalizer and is combined with
dye to change the colour of hair. It is irritating to eyes and mucous membranes
and may cause hair breakage.
· Peroxide - is a strong chemical that can injure skin and eyes,
is a known irritant and may cause hair breakage. Concentrations regulated
to 3% under the Canadian Hotlist. Its function in hair dying is to break
down the natural melanin in the hair shaft which instantly "lifts"
the colour of the hair making it lighter. The peroxide also releases oxygen,
which combines with the dye molecules and helps them to develop and deposit
colour. The depositing part is important for covering gray.
Semi-permanent Hair Colour (Levels 1 & 2)
Used to add colour to the hair but cannot produce shades that are lighter
than that originally present. Chemical process changes the colour of the
hair on the outside of the hair by depositing a bonded coating on the hair
shaft. Uses less peroxide and ammonia than permanent colouring products.
Typically the colour lasts for 8-14 shampoos but eventually washes out of
the hair. Semi-permanent dyes require no mixing as they come in liquid,
gel or aerosol foam forms. After applying the product to the hair, the user
waits 20 to 40 minutes before working it in like a shampoo and then thoroughly
rinsing with water.
Temporary Hair Colour
Used to give brighter, more vibrant shades or colours such as orange or
red - an example is colouring or streaking hair for Halloween. These products
do not bond or penetrate the hair but merely sit on the surface of the hair
and are usually washed out within the 1-2 shampoos. They are direct dyes
and do not require a catalyst as they possess an inherent colour and simply
add that to the hair. Available in various product forms including rinses,
shampoos, gels, sprays, and others.
Gradual/Progressive Hair Dyes.
Used to darken hair over time - typically grey hair. It comes in form of
a rinse and slightly darkens hair by binding to compounds on the hair's
surface. Gradual dyes are usually applied daily until a dark enough shade
is achieved, after which it may be used less often to maintain the colour.
Unlike temporary dyes, gradual dyes don't wash off readily or run when the
hair gets wet. Can contain lead acetate, a toxic ingredient and banned in
some countries. See Avoid List.
Plant-based Hair Dyes
Used to enhance natural hair colour rather than totally covering it, which allows some of your natural highlights to come through. Can cover grey. Henna, chamomile and other herbs have been used for centuries to colour hair. Specifically, henna binds to the hair shaft and is considered permanent as it does not wash out with shampoos or rinses. It is often mixed with other plant dyes, such as indigo, turmeric and sienna to change hair colour. Henna is also considered a conditioning treatment. Plant-based dyes may be difficult to apply, less reliable and predictable colour results and can cause specific reaction to an ingredient but generally are non-toxic and harmless.
Diseases implicated from Hair Dyes
o Non-Hodgkin's Lymphoma - Frequency of this cancer, which attacks the lymphatic system, has increased roughly 100% since 1950, suggesting a link with modern environmental pollutants, and the issue of toxic overload. A study conducted at the University of Washington in 1994 found a 50% increase in the incidence of N-HL in long term hair dye users. Also research has found that the risk of non-Hodgkin's lymphoma was doubled for those using darker permanent hair-colouring products for more than 25 years.
o Bladder Cancer - This illness is currently being closely studied for a connection with hair dyes. A 2001 study at the University of Southern California found a five times greater incidence of bladder cancer among hairdressers working with permanent and semi-permanent dyes than in the general population.
- Leukemia and Multiple Myeloma-Leukemia (cancer of blood producing cells) and multiple myeloma (bone marrow cancer) have both been associated with environmental pollutants, especially petro-chemical toxins (like those found in hair dyes). A National Institute of Environmental Health Science trial found that those using dyes for over 16 years had a 2.5 times greater likelihood of developing leukemia.
o Ovarian Cancer - A Harvard School of Public Health study found a two times greater risk for ovarian cancer in women who dyed their hair five times per year or more.
o Rheumatoid Arthritis - It has been found that women using permanent hair dyes for more than 20 years had double the incidence of this painful, crippling disease - long suspected of links with environmental toxins.
References
Gorgeous Hair - Can We Have it and Still Stay Healthy? Geoff
Tarbat. Vitality Wellness Journal, March 2003.
Safer Ways to Colour Your Hair, A Much Better Way, Natural Living, published
on website September 17, 2007.
Personal Use of Hair Dyes and Risk of Cancer. Bahi Takkouche. JAMA. 2005;
293:2516-2525. Vol. 293 No. 20, May 25, 2005.
Types of Hair Colouring, Nick Morante. Special Chem Cosmetics. Published
March 26, 2007.
