Frequent use of permanent hair colors can damage the hair shaft and make them dry and brittle thanks to the ammonia and hydrogen peroxide in them. With the cosmetic industry coming in the line of fire now and then for the possible harmful effects of the chemicals used in cosmetic products, you may also want to know how safe your hair color is. Whether you want to cover your grays or add highlights, lowlights, go lighter or darker, it’s essential to know what your “hair color” or “hair dye,” often used interchangeably, really entail.
Depending on how long they last, hair dyes are broadly classified into 4 types:
- Permanent (coal-tar dyes or oxidation dyes): This lasts about 8–10 weeks. It contains ammonia, which opens up the cuticle of the hair, hydrogen peroxide which oxidizes the pigment (melanin) in the hair to bleach it – also known as the developer – and a colorant like a paraphenylenediamine (PPD) or paratoluenediamine (PTD) that imparts the desired color. The amount of hydrogen peroxide required to bleach depends on your natural hair color. The darker it is, the more peroxide you need to bleach it.
- Demi-permanent: This lasts for around 6 weeks. It opens up the hair shaft partially but does not contain enough hydrogen peroxide to bleach or “lift” the hair.
- Semi-permanent hair dye: This lasts up to 6 weeks. It does not contain ammonia or a developer, so your hair is not bleached. But it may still contain PPD or PTD which deposit the color partially into the hair shafts.
- Temporary hair dye: This lasts only until the next couple of washes at best. The colors do not penetrate the shaft and only sit on the surface of your hair, outside the cuticle. However, if your hair is damaged, some of the colors may seep in.
Here are some of the possible side effects of hair dyes, listed in the order of benign to sever.
- May Cause Skin Discoloration
Skin and nails are made of the same type of keratin protein as hair. Which is why any kind of slips during the coloring process can result in patches of discolored skin, especially around the hairline. This is more likely to happen to people with dark or dry, absorbent skin. However, this shouldn’t be a massive cause for concern since your skin should be back to normal in a few days to a week, as the skin naturally renews itself and the top layer of your skin is removed. To avoid this from happening in the first place, apply a thin layer of vaseline or any oil on your hairline before coloring. Be sure to wear latex or nitrile gloves if you’re coloring your hair yourself
- Affects Hair Quality
Regular use of hair colors, especially the permanent type, can render your hair brittle and over-processed. During hair coloring, ammonia raises the pH of hair and opens up the scales in the cuticle so that the color molecules enter the next layer, the cortex. Here, through a chain of chemical reactions, hydrogen peroxide bleaches the hair and the color pigments join together to settle down on the cortex. The cuticle closes when you then rinse the hair.
First, the process of raising the cuticles artificially is the first step in hair damage since that lets the moisture escape. Second, hydrogen peroxide bleaches your hair and further dries it out. Moreover, if you happen to use more hydrogen peroxide that necessary or leave the color in for longer than instructed, there’s greater damage. There is also a possibility of free radical damage. Frequent coloring will eventually lead to dull, dry, and brittle hair and even hair loss.
New advances in hair coloring technology, however, have come up with ammonia-free products that are not only easier to use and less damaging but also fight free radical damage.
If you want to get permanent hair color, it’s best to avoid a box kit. Visit a professional salon. If you do use a box kit, look for ammonia-free products with a hydrogen peroxide volume of less than 40. Also, remember to condition your hair well before coloring it so that you don’t lose too much moisture.
- May Cause Allergies
Allergic reactions to hair dye are fairly common because PPD, a colorant, is a common allergen affecting around 1.5% of the population. People prone to contact dermatitis may be especially likely to develop an allergic reaction to the PPD. You may experience itching or swelling in the eyelids or near the ears. But in rare cases, PPD may also trigger an anaphylactic shock, a life-threatening allergic reaction.
However, for the majority of the population, PPD levels in hair products are not concerning. The FDA and the European Commission mandate that only a very low and safe percentage of PPD (2%) may be used in hair dyes and these products need to carry a cautionary note and clear usage instructions. Since PPD does not accumulate in the body, subsequent uses of hair dyes are not risky.
If you have an allergy to PPD, you could opt for a hair dye with PTD. Though these are structurally similar, in a study, 57% of the participants who were allergic to PPD could tolerate PTD well. That said, the researchers point out that they might still be allergic to other ingredients found in hair dyes and may even develop a cross-sensitization allergy later.
Watch out for PPD in temporary tattoo inks, also marketed as black henna. The FDA advises against using PPD on skin. Not only may the reaction be severe, but you may also develop a cross-sensitization to hair dye.
As a safety precaution, always perform a patch test 48 hours before coloring your hair. Instructions that come with the box of hair dye will usually recommend that you apply a small amount of the hair color solution to the inside of your elbow. You need to allow it to dry and see if you develop any allergic reactions, including rashes, itchiness, itchy eyes, pink eye, swollen eyes, wheezing, and nausea.
Safety Precautions To Take While Coloring Hair
Research may still be on the fence about the health impact of hair colors. But you can play it safe by not overusing hair dyes. For instance, reduce the frequency of dyeing your grays if you are unwilling to cut it out altogether. Always read the label and choose a product low in ammonia and hydrogen peroxide, and make sure you follow these safety precautions.
- Always strictly follow the instructions outlined on the hair color product packaging.
- Perform a patch test 48 hours before the application, especially if you’re coloring your hair for the very first time or trying a new brand. In fact, with the constant modifications in ingredients, a patch test is a good idea every time!
- Keep the color solution away from your eyes, and always wear protective gloves.
- Don’t leave the color solution on your hair longer than directed on the packaging.
- Don’t color your hair if your scalp is itchy or sunburned.
- Never use hair color on your eyelashes or eyebrows. This can be very harmful to your eyes and you even risk going blind.