More than 1 million Americans used hair coloring products at least 14 times during 2020. There are three primary types of hair dye: permanent, semi-permanent, and temporary.
To apply hair dye, almost every product requires you to rinse your hair after application. Is it really environmentally friendly to use hair dye when it will leach out and go down the drain?
There aren’t enough studies to determine how harmful to the environment hair dye is.
How does hair dye affect the environment?
Unfortunately, there aren’t enough studies to show whether hair dye harms the environment. Different hair products use a variety of ingredients, though the majority use PPD and/or hydrogen peroxide. Ammonia is another harmful chemical to the environment found in hair dye.
Even a low concentration of ammonia can be harmful to aquatic life. Ammonia is widely known to be toxic to fish at high levels, where it can build up in internal tissues and blood and ultimately result in death.
Pharmaceuticals and personal care products (PPCPs), including hair dyes, are environmental pollutants because they are still present after wastewater treatment processes. PPCPs are generally at low concentrations in surface water and groundwater and have even been found in drinking water. While hair dye is only a part of PPCP pollution, there is “mounting evidence” that contaminants in an aquatic environment “may exert detrimental impacts on aquatic life”, as summarised in a paper on PPCPs in the freshwater aquatic environment.
Some chemicals associated with hair dye can produce nitrosamines, which are toxic and carcinogenic. Nitrosamines have been found in sewage treatment plants, river water, and seawater.
PPD, or p-Phenylenediamine, is one of the primary coloring agents used in hair dye. It works in conjunction with hydrogen peroxide which bleaches the hair and ammonia (or ethanolamines). Derived from petroleum, PPD can potentially create a mutagenic substance if the user does not follow instructions. Mutagenic properties can be potentially carcinogenic. It is also potentially toxic to aquatic life when entering waterways.
Hydrogen peroxide is commonly used with hair dye, either in the hair dye product or as hair bleach. A study on hydrogen peroxide and monoethanolamine in hair dye demonstrated that dermatitis and hair loss was caused by hair dye in mice. Hair loss is also known to occur in humans with frequent usage, especially when they use lots of peroxides.
Different concentrations of hydrogen peroxide in waterways affect different aquatic organisms. Bacteria, algae, and zooplankton are less tolerant of exposure to hydrogen peroxide than fish.
Algae are producers and an essential part of food webs in aquatic ecosystems, and hydrogen peroxide can adversely affect the growth of algae. While most fish can tolerate higher levels of exposure to hydrogen peroxide, excessive amounts could drastically reduce mortality for an entire ecosystem.
Is hair dye vegan?
Many cosmetics aren’t vegan-friendly, and hair dye isn’t any different. Even some vegan hair dye companies use beeswax, milk derivatives, or honey derivatives for some of their colors. Thankfully, a lot of vegan hair dyes are available now.
Carmine, keratin, stearic acid, lanolin, glycerine, and casein are just some of the ingredients used in hair dye derived from animal products.
Popular hair dye companies like L’Oreal, Garner, Schwarzkopf, and more test their hair dyes on animals. This doesn’t necessarily mean that the company itself tests on animals, but rather that they allow it. Hair dyes sold in China are required by law to be tested on animals, though it’s possible this may change in the future.
If you’re looking for a vegan hair dye, make sure to do your research on what’s best for you. Most vegan hair dyes are semi-permanent or temporary, but there are some vegan permanent hair dyes emerging, such as Naturtint. There are even vegan hair bleach products now available to reduce reliance on hydrogen peroxide.
Are hair dyes carcinogenic?
One of the most common questions about hair dye is whether hair dye is carcinogenic. Hair dyes used to be made using by-products from the coal industry, hence the name ‘coal-tar dye’, though these by-products have been replaced by petroleum. Improvements have been made over the years, such as the removal of aromatic amines from hair dye after it was discovered they caused cancer in animals.
Coal-tar hair dyes can be permanent, semi-permanent, or temporary and are made from petroleum. They are associated with eye injuries, including blindness, and allergic reactions. The FDA states that there is no “reliable evidence showing a link between cancer and coal-tar hair dyes on the market today”.
There are some ingredients in hair dyes that have been shown to cause cancer during lab studies of animals, where animals were fed hair dye over a period of time. Dye applied to an animal’s skin has also been shown to be absorbed into the bloodstream in some studies but it has not been determined whether there is a link between skin application and cancer risk.
Other studies have found that hairdressers and barbers who work with hair dye have an increased risk of bladder cancer. The International Agency for Research on Cancer has determined that workplace exposure to hair dye is “probably carcinogenic” based on bladder cancer data.
There are mixed results on whether personal usage of hair dye increases your risk for cancer. A 2005 meta-analysis into the personal use of hair dyes and the risk of bladder cancer showed that there was no association between using hair dye and developing bladder cancer.
In 2014, another meta-analysis on hair dye use agreed that there was “no associated … observed for the highest categories of duration of use and lifetime frequency of use of both any type of dyes and permanent dyes”. However, dark-colored dyes were higher than permanent dyes, comparing the relative risks of 0.92 (permanent hair dyes) and 1.29 (dark-colored dyes).
A case-control study in Italy investigating the possible association between personal use of hair dyes and multiple forms of cancers found that permanent hair dyes resulted in a slightly increased risk of lymphocytic leukemia and black hair dye colors increased risk of developing leukemia. They did not record timing or frequency of hair dye use though.