By Rachel Leong
I recently bleached all my hair, but I wondered if hair colouring is actually dangerous. Hair bleach or lightener lightens your hair by removing melanin, your natural pigment. When the hair is light enough, you can then add on hair dye to temporarily change your hair colour. Here are some things I wish I knew before colouring my hair.
Artificial hair dye can cause skin irritation such as redness, sores, itching, and burning. This is mainly due to ammonia (alkalizing agent) and hydrogen peroxide (oxidizing agent) which are the most damaging chemicals. The effects are more serious when swallowing these toxic chemicals. Besides mouth, throat, and stomach irritation, it can also lead to severe vomiting. If the dye gets in your eye, it can even make you blind. This is why instructions say you should not use colour on your eyebrows and eyelashes.
When using bleach or hair dye properly, it should not cause cancer or brain damage. Because a lot of research done on hair dye and cancer is contradictory and inconclusive, colouring hair is unlikely to increases your chances of cancer. A study on Chinese women found that there was no significant association to breast, stomach, lung, and colorectal cancer. Before the 1980s, some hair dyes contained chemicals that caused cancer in animals. Thankfully, those chemicals have all been removed now.
The research done on the effects of hair dye on cancer is quite uncertain. Therefore, it is better to be aware of some cancer risk factors:
- Exposure type (especially hairstylists and barbers)
- Length of use (using hair dye before the 1980s)
- Frequency (how much you dye your hair)
- The colour of hair dye (black and brown dye have more chemicals)
Some alternative hair dyes exist such as henna hair dye. Henna is a natural and healthy alternative made from plants. The dye can leave your hair softer, stronger, and undamaged. However, the colours can be unpredictable and limited.
When lightening your hair, bleach breaks about 15-20% of protein bands. This makes hair very weak and string-like. To reduce breakage, using products with bis-aminopropyl diglycol dimaleate, a compound that can repair molecule bonds, is very popular and recommended.