People who want to colour their hair often get confused by the wide variety of hair colours & hair dyes available. Permanent, semi-permanent, temporary; the various types of hair color can be difficult to understand. More often than not, a person walks into a store, purchases a box of any hair dye, and ends up with unwanted results. Understanding the components of hair dye is vital to a successful coloring job. So if you are going to dye your hair, which type should you choose?
Most hair colors and hair dyes contain a chemical called p-phenylenediamine (PPD). This is the compound through which most hair colors work. PPD has the ability to stick to the hair shaft and color it.
In commonly spoken language, people use the words 'hair dye' & 'hair color' interchangeably. But, are hair colors and dyes the same? Are dyes stronger than colors? Do they work differently? If you wish to know the difference, do read our article What’s the difference between hair color & hair dye?
We explain the different types of hair colours available in market in the order of how permanent they are. These include:
- Permanent hair dyes
- Demi-permanent hair dyes
- Semi-permanent hair dyes
- Gradual hair dyes
- Temporary hair dyes
Let us discuss them one by one.
1. Permanent hair dyes
Hair colored with permanent dyes would stay forever and does not get removed by washing. Permanent hair dyes work on the principle of oxidation. They contain 4 important components:
- Colourless dye precursors like PPD
- Oxidising agents like hydrogen peroxide (in 6% concentration)
- Ammonia
- Couplers
How do permanent hair dyes work?
Permanent hair dyes color the hair in two steps:
1. remove the natural hair color
2. apply the new hair color
The dye precursors (PPD) are small molecules that penetrate deep into the hair shaft. Ammonia, present in the dye, facilitates their entry. Once inside the hair shaft, hydrogen peroxide first bleaches the natural colour of hair. It then oxidises the dye precursors to deposit new colour.
How effective are permanent hair dyes?
Permanent dyes are the most effective ones when it comes to covering gray hair. They provide 100% grey coverage even on resistant grays. All hair get uniformly colored. This, however, sometimes looks unnatural or too dark with dark shades. With permanent hair dyes, it is also possible to get a hair colour which is of an even lighter shade than natural hair. This is because the hair is initially bleached by hydrogen peroxide to let it take over new hair colour
Permanent hair dyes do not get washed off even with repeated shampooings. Hoiwever, as new hair growth appears on the scalp, re-dyeing is necessary every 4 to 6 weeks.
How to avoid reactions with permanent hair dyes?
PPD derivatives are prone to cause allergic reactions. It is important to do a patch test before applying them. On a clean area just below your elbow or forearm, apply the dye mix with a cotton swab and allow it to dry. Look out for signs of a reaction, like redness, burning sensation, itching or any other discomfort. If there is no such reaction in 48 hours, the dye can be safely used on your scalp.
Some common permanent hair dyes:
- L'Oreal Excellence Creme hair color
- Bigen Easy 'n Natural Hair Color
- Garnier Color Naturals Nourishing Permanent Hair Color Cream
- Revlon ColorSilk
- Revlon Colorsilk Luminista
- L'Oreal INOA
- Wella Kolestint
2. Demi-permanent dyes
These are chemically milder as compared to permanent hair dyes. This is because they do not contain ammonia. Also, they have lower concentrations of hydrogen peroxide (2% as compared to 6% in permanent dyes). The color molecules of demi-permanent hair dyes get deposited on the cuticle as well as penetrate into the hair cortex.
How effective are demi-permanent hair dyes?
As demi-permanent hair dyes cannot bleach the hair pigment that's already there. This is because they contain less amount of hydrogen peroxide. In other words, demi permanent hair dyes cannot lighten the pre-existing color of your hair. You can only go for either a similar or a darker shade than your present hair colour. The colour is developed and deposited just like permanent hair dyes, but is washed out in 12 to 28 shampoo washes.
Are demi-permanent hair dyes better than permanent hair dyes?
If you have upto 50% grays and want to stay close to natural hair colour, you can use demi-permanent hair dyes. The colour imparted by these dyes is not as uniform as that with permanent hair colours. So, new hair growth from roots does not look as prominent and contrasting as in case of permanent hair colour. Hence, demi-permanent dyes give a more natural color to your hair. These are gentler than permanent hair dyes, as these are less damaging to the hair shaft and less irritant to the scalp. Individuals with damaged and fragile hair can use these dyes to cover grays.
How to avoid reactions with demi-permanent hair dyes?
Just like permanent dyes, they contain PPD. As we already told you, PPD derivatives are prone to cause allergic reactions. Hence, the use of demi permanent dyes also requires a patch test, as described above in the permanent hair dye section.
Some common demi-permanent hair dyes:
- L'Oreal Casting Creme Gloss
- L'Oreal Healthy look creme gloss
- L'Oreal Color Gems Haircolor
- Bigen Powder Hair color
- Just for Men Natural Hair Color
- Streax Hair Color
- Garnier Nutrisse Hair Color
- Clairol Natural Instincts Hair Color
3. Semi permanent dyes
Semi permanent dyes contain neither ammonia nor hydrogen peroxide. The color molecules of semi permanent dyes do not penetrate into the cortex of the hair. They just get deposited on and in the cuticle (outermost layer of the hair).
Semi-permanent hair dyes can be either synthetic or natural.
Synthetic semi-permanent dyes are pre-formed dyes that contain nitro amines or nitro benzenes. Some common synthetic semi-permanent hair dyes include Garnier HerbaShine & Ion Color Brilliance Brights Semi-Permanent Hair Color.
Amongst natural semi-permanent hair dyes, Henna (or mehndi) is the commonest. We will discuss mehndi in detail in our coming article.
Indigo is another natural hair dye that is available as a green powder. When mixed with mehndi, the colour results are superior.
Vegetal Bio colour is a dermatologist-prescribed semi-permanent hair dye available in India. This is a combination of natural dyes as henna, indigo, catechu, coffee and manjistha.
How effective are semi-permanent hair dyes?
Being chemically milder, they are suitable for fragile and damaged hair. But these dyes have limited results. They can only blend upto 30% of grays. The colour gets washed off in 4 to 8 shampoo washes. Also, semi-permanent dyes can only darken your natural hair shade, and not lighten it.
Unlike permanent & demi-permanent dyes, they do not contain PPD. Thus, semi-permanent dyes usually don't cause allergic reactions. Thus, A patch test is not essential before the use of these dyes.
4. Gradual hair dyes
These are aqueous solution of metals, which when applied on hair, leave back dark shade of metal oxides or sulphides. Such metallic dyes need repeated application over a period of weeks. With each application, one can observe the gradual darkening of hair colour from grey to yellow brown to burgundy. The colour easily fades off by shampooing. Hence, gradual hair dyes need constant application. Hair perming or straightening procedures shouldn''t be done on hair coloured with metallic dyes.
Are gradual hair dyes better than the permanent ones?
These metallic hair dyes don't contain PPD. Hence these dyes are useful for individuals allergic to PPD-containing dyes. Their use doesn't need a patch test.
5. Temporary hair dyes (ideally called hair colors)
Temporary dyes consist of compounds having large sized molecules (larger than semi permanent dyes). Due to their large size, the colour does not penetrate the hair shaft. Instead, the color just sits outside the hair shaft, very close to the hair surface. Such a color can be washed out within one shampooing. But, on poor quality porous hair, even temporary dyes may get absorbed deeper, and may stay longer.
When are temporary hair dyes best used?
Temporary hair dyes are useful to brighten your original hair shade, and to add tint or enhance dyed hair. They may even come in unnatural shades as blue, pink, purple, green, gold etc. People often use them to highlight a few strands or on full head. Youngsters use them for fun, for special occasions or parties, and for sporting bold, funky colours.
We hope that now you can make more intelligent decisions while buying your next box. Stay tuned for more articles in our series on hair colors. If you liked this article, please do share it with your friends, using the social media links below!
Dr Monika Misra
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