8 Chemicals Found in Most Hair Dyes to Avoid

Posted by KatakamiYuki on

Skin absorption rates vary across body parts, with the forehead and scalp exhibiting higher absorption than the forearms. In the realm of hair coloring products, a crucial step towards informed choices is scrutinizing ingredient lists to mitigate potential risks. Join us on a journey as we explore eight common chemicals present in hair color formulations, shedding light on the importance of conscious ingredient assessment for the promotion of overall well-being.

Could you look at the ingredients list on your hair color and hair care products?

chemical hair color

1. P-phenylenediamine PPD

PPD is short for para-phenylenediamine. It is used as a dye for dark color shades and is made from coal tar, a petroleum-derived chemical that includes benzene, naphthalene, phenols, aniline, and other chemicals. It is also used as a wood preservative, and contact with skin is best avoided.
PPD can cause reactions ranging from mild skin irritation to more severe allergic contact dermatitis.[1] Sensitive individuals may experience dermatitis—skin inflammation and irritation commonly called eczema. In more severe cases, there may be marked reddening and swelling on the scalp and the face. An allergy to PPD can result in widespread contact dermatitis, hives, and, in rare severe cases, anaphylaxis.

2. Hydrogen peroxide

Hydrogen peroxide

Hydrogen peroxide is oxygen water. It is the activator that you add to the color cream when you dye your hair. Peroxide is used as the developer or oxidizing agent. It removes pre-existing color.
Hydrogen Peroxide is said to change the hair structure and make it brittle, stripping it of its natural luster. [2]

3. Ammonia


Ammonia is used to open up the hair’s cuticle (the outer layer), so the dyes can come into the shaft (the inside of the hair).
Ammonia can cause skin irritation, and if it gets into your bloodstream, you could get sick. Ammonia can also impact the earth by endangering animals in the ocean and crops on the land.

4. Ethanolamine


Ethanolamine is used in our demi-permanent hair colorants instead of Ammonia.
Ethanolamine is similar to ammonia but can damage your hair more.[3] You may also notice more hair loss, and there can even be a risk of birth defects.

5. DMDM hydantoin

DMDM hydantoin

DMDM hydantoin is a formaldehyde releaser or donor. It slowly releases the chemical formaldehyde as it breaks down in the product over time to prevent mold and bacteria from growing. It works by slowing or stopping the growth of potentially harmful microbes such as fungi, yeast, and bacteria. DMDM hydantoin has come under fire in recent years because it releases small amounts of formaldehyde. It may cause tissue irritation and affect the immune system.

6. SLS


Before you use your go-to hair color, check for these ingredients: sodium Laureth sulfate, sodium lauryl sulfate, or sodium chloride. These ingredients act like a deep-cleaning detergent that can strip your hair of its new color. It strips your hair of dirt and essential, natural oils that can leave your hair weak and prone to breakage. Continuous exposure to sodium Laureth sulfate can even cause skin irritations.

7. Resorcinol


Resorcinol (or benzene-1,3-diol) is a chemical commonly used in hair color, hair dyes, skin peels, and during acne treatments. It reacts with the peroxide-containing developer to give the required color or shade.
Resorcinol is a toxic dye that can cause scalp irritation and is an allergen affecting the endocrine system.

8. Methylchloroisothiazolinone


Methylchloroisothiazolinone is a preservative in many skin care products, household cleaners, and hair dye products that stop fungi, yeast, and bacteria from growing. Methylisothiazolinone engages your immune system and irritates your skin.[4] Once this happens, you may become permanently allergic to methylchloroisothiazolinone the next time you are exposed.


Did you know your hair undergoes a complete transformation approximately every seven years? 

Toxins can persist in your hair for up to seven years. Consequently, daily choices, including exposure to coloring and perming agents, can damage the hair's cuticle, leading to brittleness, breakage, and premature aging.


There are plenty of plants- and henna-based hair colors out there that offer a safer and less damaging alternative to traditional chemical dyes. 100% Organic hair dye is safer than Natural hair dyes. Organic hair dye is hair color made from organic botanical components (usually meaning free from pesticides) without being subject to specific damaging chemical processes. Radico's hair colorants contain only natural, certified organic ingredients.

non-toxic hair color



1. Han JH, Lee HJ, Bang CH, Lee JH, Park YM, Lee JY. P-Phenylenediamine Hair Dye Allergy and Its Clinical Characteristics. Ann Dermatol. 2018 Jun;30(3):316-321. doi: 10.5021/ad.2018.30.3.316. Epub 2018 Apr 23. PMID: 29853746; PMCID: PMC5929949. 

2. Malinauskyte E, Cornwell PA, Reay L, Shaw N, Petkov J. Effect of equilibrium pH on the structure and properties of bleach-damaged human hair fibers. Biopolymers. 2020 Nov;111(11):e23401. doi: 10.1002/bip.23401. Epub 2020 Sep 14. PMID: 32926408; PMCID: PMC7757171.

3. Ali N, Marsh J, Godfrey S, Williams DR. Aqueous MEA and Ammonia Sorption-Induced Damage in Keratin Fibers. ACS Omega. 2018 Oct 31;3(10):14173-14180. doi: 10.1021/acsomega.8b01189. Epub 2018 Oct 25. PMID: 30411060; PMCID: PMC6217691.

4. Scherrer MA, Rocha VB, Andrade AR. Contact dermatitis to methylisothiazolinone. An Bras Dermatol. 2015 Nov-Dec;90(6):912-4. doi: 10.1590/abd1806-4841.20153992. PMID: 26734880; PMCID: PMC4689087.

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  • It’s a great article about ammonia free hair colour Thank you

    Samar Kumar on

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