Is Natural Hair Dye Really Safer Than Conventional?

(image credit: By Dean Wissing)

Do you color your hair? I think it is very likely that you do and that you therefore also have seen the warning texts on the conventional hair dye packaging regarding cancer and allergies.

Because of this you might have started to use a “natural hair dye” as an alternative to conventional dyes and are convinced that this is a better and healthier alternative? Think twice. This may not always be the case.

A study in the U.K. in 2013 revealed that one in six women had no idea what their original hair color is, as they have been coloring their hair for so long. The beauty and cosmetics industry is booming and remained stable throughout the entire recession. This industry brought in global revenue of $155-255bn in 2014 and is estimated to grow to $316bn by 2019.

There is a lot of money in beauty. Hence, it should not really come as a surprise that producers may be motivated to do some cosmetic touch-ups about the truth about some of their products, both “natural” and “synthetic” ones.

I want to color my hair without risking cancer! Should I choose a natural hair dye?

After entering some sort of midlife crisis I started coloring my hair dark red. I really love the color, but every time I color my hair, the long warning texts on the packaging daunt me somewhat.

My midlife crisis also has prompted many morbid thoughts: I suddenly found myself thinking about everything that could be unhealthy and bad for me, and death. The warning texts on the dye packages scared me more and more: I don’t want to get cancer and die! But then my rational self stepped in: Are the dyes as bad as they indicate and are the “natural” and organic dyes really any better? I needed to find out more.

Some bastards have beautiful natural hair color (image credits: collage:Jujutacular. source image: Rama, Jastrow, Mattbuck)
Some bastards have beautiful natural hair color (image credits: collage:Jujutacular. Source image: Rama, Jastrow, Mattbuck)

Is “natural hair dye” better than “synthetic hair dye”?

Synthetic dyes, despite being quite harsh chemically, work well and the hair will remain that color. Then there are “natural dyes” whereof henna is one alternative. Just beware that these dyes often do not only contain the henna plant extract, but also a lot of other “synthetic” chemicals and metal salts (sometimes even lead).

The second “natural” option is to make your own vegetable dyes at home and progressively dye your hair over a long period of time to achieve a slight taint in your hair (for example, black tea-rinses makes it darker).

The so called natural dyes do not last as long as the synthetic ones since they do not penetrate the hair cuticle.

What is the danger with synthetic dyes?

Unfortunately most of the synthetic dyes do contain components that are carcinogen and can penetrate the skin for example 4-MMPD, 2,4-diaminoanisole which has to be labeled with the warning:

Warning – Contains an ingredient that can penetrate your skin and has been determined to cause cancer in laboratory animals.

Other examples of carcinogen compounds contained in dyes are: 4-chloro-m-phenylenediamine, 2,4-toluenediamine, 2-nitro-p-phenylenediamine and 4-amino-2-nitrophenol.

However (and this is important!), the studies that have been made with regard to the carcinogen properties of synthetic hair dyes have shown that due to the rare exposure to the dyes: about once a month and for 30 min, exposure does not constitute a high risk. Once again,

The dose makes the poison and hairdressers and many others working in the cosmetics industry are exposed to very high levels of these compounds.

Nonetheless, the greatest risk of these “synthetic” dyes comes not from them being carcinogen, but from the high risk of getting an allergic reaction. This risk can be just as high in many so called “natural” dyes, particular for the so called “composite hennas” that  I discuss below.

You should never color your hair whilst being pregnant since your baby might be exposed to unnecessary mutagens and if you would get an allergic reaction to the dye, your baby will be in severe danger.

The hair coloration business has been a bit of a Wild West regarding chemical certifications. This is mostly due to legislative issues since the hair dyes are not as tightly controlled as creams and lotions that one applies directly onto the skin.

natural hair dye vs conventional hair dye
Synthetic dyes – a booming industry (image credit: Masahiko OHKUBO)

Did you know that “henna” can contain metal salts including lead?

There is a big difference between henna and composite henna. However, composite henna is often branded as just “henna”. Henna is pretty harmless, whereas composite henna can be just as bad as conventional “synthetic” dyes.

Henna is ground leaves or bark from the bush Lawsonia inermis and it has a long been used in the Middle East and Africa in the coloration of hair and making of temporary tattoos.  The natural color of the henna dye is a brown-reddish color. If the dye has other hues, it has been tampered with.

To achieve different colors than just brownish-red, metal salts may be added to the henna powder. It is these metal salts that do not agree with commercial dyeing products later on if you decide to stop using henna and start using a synthetic dye instead. Your hair might turn green.

henna - natural hair dye
Henna powder for hair (image credit: Andrey “A.I.” Sitnik)

Is henna powder dangerous?

There are some henna producers that sell a composite henna of sorts, but the ingredients have been restricted to merely contain the plant Indigo (Indigofera tinctoria) and Henna bark (Lawsonia inermis). There are also many other plant extracts that are used to tweak the color of the henna dyes.

I checked up Indigo on the European Commission’s Scientific Committee on Consumer Safety’s (SCCS) website and it seems like Indigo is fairly harmless, though it is a weak skin irritant. Nonetheless, SCCS mention that there is too little data to conclude if it is carcinogen, but they deem it unlikely.

Henna bark is considered safe to use as a dye and very few cases of allergic reactions have been registered.  However, SCCS calls for more research on genotoxicity (that would be if it causing cancer) since there is not enough data collected to be able to answer that.

The SCC clearly state that what they are testing in this particular report is: the clean henna bark and not composite henna. They clearly state that this should not be confused with black henna that may show completely different toxicity.

Did you know that black henna can be just as toxic as synthetic dyes?

Interestingly, many black henna products contain the one compound that is discussed the most regarding toxicity of synthetic dyes: para-phenylenediamine (PPD). PPD is a compound is found in virtually all synthetic hair dyes. PPD and its derivative compounds like 4-methoxy-m-phenylenediamine (4-MMPD) have been shown to be carcinogen by the FDA.

PPD can also often be found in unregulated black tattoos. Despite the danger of PPD black henna is on a rise globally and particularly in the use by children and adolescents. PPD may cause strong allergic reactions ranging from skin issues such as dermatitis to full blown anaphylactic shock. Is dyeing your child’s hair really worth the risk?

What is the difference between “organic hair dye” and “natural hair dye”?

 “what is organic”?

This seems like an easy question to answer, but contains many pitfalls. Do you mean “organic” as in and eco-labelled products that have to comply with a certain set of regulations and laws, or do you use “organic” as a synonym for “natural” and plant-based dyes?

There is a big difference. Obviously, there are natural henna products that are indeed organic: grown according to a certain label’s standard. However, there is no difference between these organic and non-organic products regarding their toxicity to humans when used as dyes.

Furthermore, here are major issues with the label “organic”. It can mean a lot of things and the labels can be quite misleading. One tip is to investigate if the label used is a so called TYPE I label certified by the International Standardization Organization (ISO). These labels are independently checked by third party organizations.

However, even these labels can vary much in their criteria. Eco-labeling is a jungle. Nonetheless, the term “organic” is used extremely sloppy, particularly in the U.S.

The beauty industry is a $300bn industry. Of course they will use every loop-hole there is to sell more products regardless if they are “natural” or “synthetic”. Therefore, many “organic” dyes include something like 30 % truly eco-labeled ingredients (whatever that means) and the rest is just your normal chemicals used in dyes. Know your eco-labels and understand the regulations around them with respect to the different products.

Yes, I know, it is virtually impossible, but I will try to help clarify the issue on hair dyes in this article.

So, why are chemicals needed in hair dyes?

Hairs are made up of protein fibres, just like many natural textile fibres like wool. To ensure that the dye enters the hair and remains there, the hair first has to be treated with ammonia and hydrogen peroxide so that the protective layers open and allow the dye to enter the hair shaft.

The hydrogen peroxide removes the natural color of the hair and reacts with the dye to make a new color. Often the molecule that produces the color is the toxic compound para-phenylenediamine (PPD).

The legal loophole

There is a legal loophole that commonly is used for cosmetics in the U.S.: all cosmetics have to be labeled with their content. This falls under the Fair Packaging and Labeling Act (FPLA). However, this law does not apply to professionals using the products. This is why it is sometimes difficult to know the products actually contain if you go to a salon.

Also, non-approved coal-tar products (PPD is a coal-tar derivative) with known adverse effects may be used in products provided the product is labeled properly with a warning text such as:

Caution – This product contains ingredients which may cause skin irritation on certain individuals and a preliminary test according to accompanying directions should first be made. This product must not be used for dyeing the eyelashes or eyebrows; to do may cause blindness.

Albeit, this is not the case for non-approved metallic or vegetable dyes: They must be labeled. I find this somewhat peculiar since coal-tar products have indeed been shown to have real detrimental effects on both the ecosystem and human health.

Some very unscientific claims

Skin Deep – a non-scientific toxicity data base

During this research I also encountered the Skin Deep database that has been set up by the Environmental Working Group (EWG). Despite at first being excited about discovering a nice and accessible database on compound toxicities for the general public, my joy rapidly dissipated when I started to click my way through the lists.

There were absolutely no data on dose-responses. Remember that

“The dose makes the poison”.

For example, Coffea arabica was labeled as “carcinogen” in the Skin Deep database. Seriously, guys! We are talking about coffee beans that are not even ingested, but added to the scalp in tiny amounts.

I cannot recommend the EWG Skin Deep data base. I find it unscientific and fear mongering and it takes away the focus on the chemicals in our environment that really should be banned and removed from the marked due to ecological or human health reasons.

Gluten free hair dye – what the world needs!

Many of these “natural hair dye” products are also labeled gluten free. Gluten is a large molecule and is not absorbed by the skin. These misunderstanding often originate due to a type of celiac disease (gluten intolerance) called herpetiformis (DH) which causes nasty rashes on the skin.

People think that DH is caused by skin-contact with gluten, but it is caused by ingestion of gluten. The only way you could get it is if you would lick your fingers after having used skin lotions containing gluten. There are very few people with celiac disease who are so sensitive that they would react to the tiny amounts gluten that they might ingest from a lip balm.

To think that a gluten free hair dye is necessary is stretching the truth a bit in my opinion. During all my years of dyeing my hair, I have yet to ingest some of the product and if I would get some in my mouth, I seriously doubt that gluten would be my first concern…

Some funny claims I found:

“Morrocco Method Int’l has provided the world’s finest in raw, vegan and paleo hair care for more than 40 years. All of our products are sulfate free, gluten free, and all natural. “


“Gluten-free. vegan. no corn derivatives. No synthetic chemicals”.

But, can someone explain why no corn it important and why it should be raw?!? I don’t get it. …and paleo? I am sure we know a lot about the hair dyeing practices of the cave men.

Selling chemicals without chemicals

I encountered some quite funny pages during this research. Rainbow Henna for example writes on their page:

“Rainbow Henna has no additives, chemicals, or pesticides”

They are selling chemicals with no added chemicals… but I am glad to hear that there are no additives added to chemical-free chemicals.  Once again, an example of a fundamental misunderstanding of what a chemical is and this is very typical for this sort of business.

Another favorite is the claim that using organic soap (instead of a non-organic one) in one’s hair before and after dyeing would keep the color longer. I still fail to see how the origin (organic/non-organic) of the fatty acids and glycerols in that soap would have anything to do with the outcome of the dying. But as health guru David Wolfe says:

“Chocolate is an octave of the sun”.

… Nothing in this business needs to make sense as long it is natural.

Time to swap your dye to a more ecological one?

In this case, pure henna with no additives except perhaps indigo, seems to be the most ecological and healthy way to dye your hair unless you want to use Earl Gray tea, but you might end up looking like a menopausal carrot.

Synthetic dyes, as well as many composite henna dyes, contain many dangerous chemicals and metal additives that might cause severe allergic reactions. However, pure henna is not completely harmless, it just means that it is a lesser “evil” alternative.

It is important to remember that the rare and short exposure to the dyes makes their carcinogen properties less of a concern (the dose makes the poison).

However, in my opinion, there is one very real concern: Most sewage treatment plants are not equipped to deal with these sorts of chemicals (including henna), which then results in it all landing in your closest aquatic ecosystem. This is in my opinion the greater concern than the human health issue. Be nice to our waterways: we depend on them for our survival.

I might actually consider swapping my dye to a more ecological one like pure henna, since I like my hair menopausal red anyhow.

Do you color your hair and have you ever been worried about the warning texts on the packages? Do you also think that it is peculiar that we can ignore proven chemical toxicity just because of vanity, but get our knickers in a twist because of vague suspicions of carcinogen chemicals in other things like lotions?  What are your thoughts on the matter?


U.S. Department of Health and Human Services. Registry of Toxic Effects of Chemical Substances (RTECS, online database). National Toxicology Information Program, National Library of Medicine, Bethesda, MD. 1993.

Goldenberg, A., Jacob, E. Paraphenylenediamine in black henna temporary tattoos: 12-year Food and Drug Administration data on incidence, symptoms, and outcomes (2015). vol 72, issue 4, pp 725-726. DOI: http://dx.doi.org/10.1016/j.jaad.2014.11.031

Vogel, T.A., Coenraads P.-J., Schuttelaar M. (2014). Allergic contact dermatitis presenting as severe and persistent blepharoconjunctivitis and centrofacial oedema after dyeing of eyelashes. Contact Dermatitis, 71, 303–317. doi:10.1111/cod.12272

Marietta, Eric V.; Murray, Joseph A. Animal models to study gluten sensitivity (2012) SEMINARS IN IMMUNOPATHOLOGY  Volume: 34   Issue: 4   Pages: 497-511   Published: JUL 2012

FDA FACT SHEET: http://www.fda.gov/Cosmetics/ProductsIngredients/Products/ucm143066.htm

The effects of henna (hair dye) on the embryonic development of zebrafish (Danio rerio) By: Manjunatha, Bangeppagari; Peng Wei-bing; Liu Ke-chun; et al. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH  Volume: 21   Issue: 17   Pages: 10361-10367   Published: SEP 2014

Study on hair dyeing wastewater treatment by the union process of Adsorption Coagulation and Potassium Permanganate Oxide. By: Yin, Jun; Hu, Ying. Edited by: Zhang, L. Conference: 2nd International Conference on Renewable Energy and Environmental Technology (REET) Location: Dalian, PEOPLES R CHINA Date: AUG 19-20, 2014. ENVIRONMENTAL TECHNOLOGY AND RESOURCE UTILIZATION II  Book Series: Applied Mechanics and Materials   Volume: 675-677   Pages: 638-642. Published: 2014

Human systemic exposure to [C-[14]-paraphenylenediamine-containing oxidative hair dyes: Absorption, kinetics, metabolism, excretion and safety assessment. By: Nohynek, Gerhard J.; Skare, Julie A.; Meuling, Wim J. A.; et al. FOOD AND CHEMICAL TOXICOLOGY  Volume: 81   Pages: 71-80   Published: JUL 2015

Maternal hair dye use and risk of neuroblastoma in offspring. By: McCall, EE; Olshan, AF; Daniels, JL. CANCER CAUSES & CONTROL  Volume: 16   Issue: 6   Pages: 743-748   Published: AUG 2005

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