Impurities in cosmetics; chemicals not listed in the INCI list

Many of you are certainly familiar with the mandatory cosmetic product ingredient list, the INCI -list. The package of each commercial cosmetic product must include a list of raw materials indicating all the ingredients contained in the product. Unfortunately, not all information can be found on INCI. There is a group of very dangerous or allergenic substances that can be left out from the list. These substances are impurities in the raw materials of cosmetics.

What are these contaminants and where do they come from? In this article, I will tell you about the seven most common ingredients hidden in cosmetics.

Photo by Nataliya Melnychuk on Unsplash


Nitrosamines are very harmful chemicals. They are not found in the INCI list of products because they are hidden inside other ingredients. Nitrosamines have been classified by the International Agency for Research on Cancer as potentially carcinogenic chemicals. In addition, nitrosamines have been found to cause hormonal disorders even in very small amounts.

Nitrosamines can be found in just about any cosmetic that contains preservatives. Ingredients used in the manufacture of preservatives may be contaminated with nitrosamines. Currently, 55 different chemicals that may contain nitrosamine have been studied. The most common of these substances are harmless lecithin as well as hydrogenated lecithin. That is why it is especially important to pay attention to the quality of the ingredients. High quality lecithin does not contain dangerous impurities.

Ethylene oxide

Ethylene oxide is a very harmful chemical to which we are exposed quite often. Ethylene oxide is actually used in hospitals for disinfection. Ethylene oxide can be used to disinfect instruments and equipment that cannot tolerate heating. In hospitals, of course, this is important. Ethylene dioxide is also used to treat spices, seeds and beans. Ethylene oxide stops unwanted microbial growth in foods without heating. The ethylene oxide content of food is closely monitored. Sometimes we get warnings about products removed from shops due to excessive ethylene oxide content.

Ethylene oxide is a carcinogenic chemical. Excessive exposure to ethylene oxide has also caused mutagens, fertilization problems and sensitization.

Where can ethylene oxide be found in cosmetics? Synthetic emulsifiers such as polysorbate-20, polysorbate-60 and polysorbate-80 may have residues of ethylene oxide. Ethylene oxide may also be found in all PEG compounds. PEGs are commonly used in cosmetics for many different purposes. You can read more about PEG compounds here.

Ethylene oxide can also end up in homemade cosmetics if you have used dried herbs (thyme, rosemary) in oil extracts. Ethylene oxide may also be present in seeds such as sesame seeds and sunflower seeds. The product descriptions of herbs and seeds do not need to mention ethylene dioxide treatment. You should get all the cosmetic ingredients as organic as possible.

1,4 dioxane

1,4 dioxane is a very common hidden chemical in cosmetics. From the same products where you can find ethylene dioxide, you can also find 1.4 dioxanes as they are produced in the same process. 1.4 Dioxane is most commonly found in foaming products like bath foams and shampoos. The International Agency for Research on Cancer classifies 1,4-dioxane as a potential carcinogen.

 Cosmetic products are also tested for 1.4 dioxane. However, testing is not complete. Therefore, it is better to avoid the same PEG compounds and the above-mentioned polysorbates.


Acrylamide is classified as a human carcinogen. Acrylamide can be formed in the product when treated at high temperatures (baking). Many fried foods may therefore have high levels of acrylamide.

No maximum levels have been set for acrylamide. However, there is a recommendation to avoid acrylamide in the EU Commission legislation.

Acrylamide is found contaminated in products containing polyacrylamide, polyacrylic acid or polyquaternium-7.


Formaldehyde is recognized as a carcinogen. The European Union severely restricts the use of formaldehyde. Formaldehyde is quite often found in nail polishes, hair sprays and lash adhesives. A very common source of formaldehyde is preservatives that contain formaldehyde releasers. I have written a separate article about formaldehyde. You can read it here.


Hydroquinone is a compound that can co-occur with vitamin E (tocopherol) and its derivatives. Hydroquinone can be formed in products during the manufacturing process.

Hydroquinone is classified as a harmful product. It has been shown to cause severe skin and eye burn at short-term exposure. Hydroquinone belongs to the group of dangerous chemicals. It can potentially cause cancer and potentially damage the genome. It has also been suspected of causing allergies as well as skin changes.

Hydroquinone is used creams for whitening age spots and freckles. In nature, hydroquinone is found, for example, in beeswax.

PAHs (polycyclic aromatic hydrocarbons)

PAHs are chemicals that have been studied for decades. They have been found to cause cancer in humans. Breast cancer in particular is often associated with PAHs. PAHs can be present in both food and cosmetics.

PAHs are found in cosmetics that use crude oil, gasoline, or coal. Such products are products containing Vaseline and/or products containing coal tar. Ordinary wood tar can be used without worries. Hydrogenated palm oil also contains PAHs.

How to avoid harmful hidden chemicals?

Photo by Nataliya Melnychuk on Unsplash

These aforementioned impurities are just examples of compounds that have been hidden in cosmetics. Cosmetics may also contain pesticide residues and environmental toxins. In addition, the raw materials may contain other chemical residues due to the treatment.

If you want to use conventional cosmetics, watch the INCI list. Avoid products that use PEG compounds. PEGs as well as polysorbate-80 and polysorbate-20 are so common in cosmetics that they are quite unavoidable. I recommend that you choose an unscented product. Many fragrances contain incredibly harmful compounds.

The best way to avoid contaminated cosmetics is to buy and make natural cosmetics. Most of the listed chemicals are present in preservatives or fragrances that are not allowed in natural cosmetics. By choosing a natural cosmetics -quality product, you will also avoid most of the hidden chemicals in cosmetics.

Are you worried about cosmetic impurities?

2 answers

  1. Detection and quantification of harmful impurities especially nitrosamines and derivatives in Cosmetic products remains a major challenge to Chemists

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