Ingredient categories to avoid in a shampoo
October 26, 2026Ingredient categories to avoid in a shampoo

“Sulfate-free,” “silicone-free,” “paraben-free”… With so many claims crowding shampoo labels, it’s hard to know what ingredients to avoid in shampoo, and above all why. The good news: you don’t need to be a chemist to make an informed choice. You just need to know what to look for on the label.

Here are 10 categories of ingredients to avoid in shampoo, what scientific and regulatory authorities actually say about them, and our tips for spotting a healthier shampoo for you and for the environment.

Are There Bad Ingredients in Shampoo?

The honest answer is nuanced. In Canada, the Food and Drugs Act prohibits the sale of a cosmetic that contains a substance that may cause injury to the health of the user when used normally. Health Canada maintains the Cosmetic Ingredient Hotlist, an administrative tool that identifies prohibited and restricted substances.1 In the United States, the FDA does not approve cosmetic products or ingredients before they go on the market, except for certain color additives, but it is illegal for a cosmetic to contain an ingredient that makes it harmful when used as directed. In addition, the FDA prohibits or restricts a short list of substances.2,3 In both countries, an ingredient that is neither prohibited nor restricted can therefore be used, as long as the product remains safe. That doesn’t mean everyone wants to use it. How do you tell harmful shampoo ingredients from merely controversial ones? By looking at the evidence.

At ATTITUDE®, we apply responsible science and the precautionary principle. When an ingredient raises questions, we prefer to choose an alternative. The 10 categories below rely on scientific sources, not fear.

10 Shampoo Ingredients to Avoid

1

Formaldehyde releasers

On the label: DMDM hydantoin, diazolidinyl urea, imidazolidinyl urea, quaternium-15.

These preservatives slowly release formaldehyde into the formula. The International Agency for Research on Cancer (IARC) classifies formaldehyde as carcinogenic to humans (Group 1), based on sufficient evidence linking exposure, mostly occupational, to nasopharyngeal cancer.4

2

Ethoxylated ingredients

On the label: sodium laureth sulfate (SLES), ceteareth-, laureth-, PEG-, PPG-, polysorbate-.

These surfactants and emulsifiers are made through ethoxylation, a reaction with ethylene oxide, which IARC classifies as carcinogenic to humans (Group 1).5 The process can leave traces of 1,4-dioxane, an impurity that IARC classifies as “possibly carcinogenic to humans” (Group 2B).6

These residues are not intentionally added, and their risk depends on their quantity, and therefore on how well the raw materials are purified.7,8 We prefer not to rely on them.

3

Ethanolamides (DEA)

On the label: cocamide DEA, lauramide DEA and other ingredients with “DEA” in the name.

IARC classifies cocamide DEA as “possibly carcinogenic to humans” (Group 2B), based on studies in mice, with no human data.9 Since the FDA does not see a reason for alarm either,10 the key is to know how to spot these ingredients on the label so you can make your own choice.

4

Isothiazolinones

On the label: methylisothiazolinone (MIT), methylchloroisothiazolinone (MCI).

Methylisothiazolinone is a preservative behind a rise in contact allergies, to the point that the European Union has banned it from leave-on products since February 2017.11 For rinse-off products such as shampoos, the Scientific Committee on Consumer Safety (SCCS) concluded in 2015 that a concentration of 100 ppm could not be considered safe, but that 15 ppm was, from the standpoint of inducing contact allergy.12

5

Long-chain parabens

On the label: propylparaben, butylparaben (and their derivatives).

The SCCS considers propylparaben safe up to 0.14%, while noting that the data hint at possible endocrine effects.13 In 2023, it reached the same limit for butylparaben, specifying that the lack of exposure data for children means safety concerns cannot be ruled out.14

6

Triclosan

On the label: triclosan.

Health Canada limits its concentration to 0.3% in cosmetics other than mouthwash and concludes that, at the exposure levels assessed, it is not harmful to human health.15 Its problem is rather environmental: it is not completely removed from wastewater, it is highly toxic to aquatic organisms such as algae and fish, and it is listed on Schedule 1 of the Canadian Environmental Protection Act, 1999, the List of Toxic Substances.15

In the United States, the FDA determined in 2016 that triclosan and 18 other ingredients are not generally recognized as safe and effective in consumer antiseptic wash products rinsed off with water, such as hand and body soaps and washes.16

7

Artificial dyes

In Canada: CI followed by a number (e.g., CI 42090), or a color name followed by a number (e.g., Blue 1, Yellow 6).17
In the United States: color name and number preceded by FD&C, D&C or Ext. D&C (e.g., FD&C Yellow No. 6), or the short form (e.g., Yellow 6).18

A dye has no cleansing role: it is there only for looks. Certifiable artificial dyes are human-made and come primarily from petroleum and coal.19 Reactions are rare, but an allergic-type reaction is possible: for example, FD&C Yellow No. 5 (Yellow 5) can cause itching and hives in some people, and it is found in foods, drugs and cosmetics.19

8

Silicones

On the label: dimethicone, amodimethicone, cyclopentasiloxane (D5), cyclomethicone.

Silicones coat the hair fiber to give an instant feeling of softness. On the environmental side, Environment Canada and Health Canada concluded in 2008 that D5, a cyclic siloxane, is persistent in air, water and sediment and is not readily biodegradable, and may therefore have a long-term harmful effect on the environment. They found, however, that it does not constitute a danger to human health.20

9

Undisclosed fragrances

The terms “fragrance” and “parfum” can group several components without naming them, which makes choosing harder for sensitive people.21 To earn the EWG Verified® mark, a product must meet EWG’s disclosure standards and disclose all of its ingredients to EWG, including those in the fragrance. It also cannot contain any ingredient on EWG’s “Unacceptable” list, meaning ingredients with health, ecotoxicity or contamination concerns.22

Our shampoos are EWG Verified®: their fragrances therefore contain no ingredient from EWG’s “Unacceptable” list, are fully disclosed to EWG, and every one of their ingredients is listed on our labels.

10

Fragrance allergens

On the label: limonene, linalool, citral, geraniol, eugenol, cinnamal, coumarin, farnesol.

These compounds are among the 26 fragrance allergens that must be labeled in the European Union, according to the SCCS.23 Canada also requires them to be declared in the ingredient list: since April 12, 2026 for 24 allergens (including all eight above), when they exceed 0.01% in a rinse-off product such as a shampoo, and since August 1, 2026 for the expanded list of 81 entries in new cosmetics (from August 1, 2028 for existing products).17 Beware: natural doesn’t mean allergen-free. The SCCS identified 28 natural extracts among established contact allergens.24

When they are present in our products, these compounds are listed on the label, and our unscented shampoos are an option for sensitive skin and scalps.

How to Choose Your Shampoo

If, like us, you’re looking for ingredients of natural origin, here are a few tips for spotting a good shampoo:

✓Read the full ingredient list, not just the “free-from” claims on the front. A “paraben-free” claim says nothing about the preservative that replaces it.
✓Look for a recognized certification, such as EWG Verified®. According to EWG, products that carry it contain no ingredient of concern and meet its transparency criteria.22
✓Check unfamiliar ingredients in Health Canada’s Cosmetic Ingredient Hotlist1 or, in the United States, in the FDA’s short list of prohibited and restricted ingredients3, as well as in EWG’s Skin Deep® database.

To learn what to look for instead of what to avoid, read our article 10 Ingredients to Look For in a Shampoo. And to find the shampoo that suits your hair, see Selecting the Right Shampoo for Your Hair Type.

Unwanted Substances in Shampoo: What’s the Impact?

FOR YOU

The Impact on Health

Authorities assess each ingredient individually, at its use concentrations. Health Canada in fact concludes that, at current exposure levels, many substances are not harmful to the health of the general population.8,15 Reactions do vary from person to person, however: a contact allergy, once triggered, persists.24

FOR THE PLANET

The Impact on the Environment

A shampoo gets rinsed off, and its ingredients end up in wastewater. Triclosan is highly toxic to aquatic organisms15, and D5 is persistent in water and sediment.20 That’s why our formulation choices take the health of the environment into account, not just yours.

Our Shampoos: Formulated With Ingredients of Natural Origin, Transparent and Effective

At ATTITUDE®, we believe in questioning everything, including our own formulas, and we invite you to do the same. Our shampoos are carefully designed with the impacts on human health and on the environment in mind, are formulated with ingredients of natural origin25 and contain fragrances that meet EWG Verified® criteria.

Discover our shampoos, available in eco-refills and as plastic-free shampoo bars, to reduce your plastic consumption.

References

[1] Health Canada. Cosmetic ingredient hotlist: prohibited and restricted ingredients [Internet]. Ottawa (ON): Government of Canada; 2004 [updated 2026 Mar 31; cited 2026 Oct 26]. Available from: https://www.canada.ca/en/health-canada/services/consumer-product-safety/cosmetics/cosmetic-ingredient-hotlist-prohibited-restricted-ingredients.html

[2] U.S. Food and Drug Administration. Cosmetics & U.S. law [Internet]. Silver Spring (MD): FDA; [cited 2026 Oct 20]. Available from: https://www.fda.gov/cosmetics/laws-regulations/cosmetics-us-law

[3] U.S. Food and Drug Administration. Prohibited & restricted ingredients in cosmetics [Internet]. Silver Spring (MD): FDA; 2022 [cited 2026 Oct 20]. Available from: https://www.fda.gov/cosmetics/cosmetics-laws-regulations/prohibited-restricted-ingredients-cosmetics

[4] IARC Working Group on the Evaluation of Carcinogenic Risks to Humans. Formaldehyde, 2-butoxyethanol and 1-tert-butoxypropan-2-ol. Lyon (FR): International Agency for Research on Cancer; 2006. (IARC Monographs on the Evaluation of Carcinogenic Risks to Humans; vol. 88). Available from: https://www.ncbi.nlm.nih.gov/books/NBK326456/

[5] IARC Working Group on the Evaluation of Carcinogenic Risks to Humans. Ethylene oxide. In: Chemical agents and related occupations. Lyon (FR): International Agency for Research on Cancer; 2012. (IARC Monographs on the Evaluation of Carcinogenic Risks to Humans; vol. 100F). Available from: https://www.ncbi.nlm.nih.gov/books/NBK304417/

[6] IARC Working Group on the Evaluation of Carcinogenic Risks to Humans. 1,4-Dioxane. In: Re-evaluation of some organic chemicals, hydrazine and hydrogen peroxide. Lyon (FR): International Agency for Research on Cancer; 1999. p. 589-602. (IARC Monographs on the Evaluation of Carcinogenic Risks to Humans; vol. 71). Available from: https://inchem.org/documents/iarc/vol71/019-dioxane.html

[7] U.S. Food and Drug Administration. 1,4-Dioxane in cosmetics: a manufacturing byproduct [Internet]. Silver Spring (MD): FDA; 2022 [cited 2026 Oct 20]. Available from: https://www.fda.gov/cosmetics/potential-contaminants-cosmetics/14-dioxane-cosmetics-manufacturing-byproduct

[8] Health Canada. 1,4-Dioxane [Internet]. Ottawa (ON): Government of Canada; 2009 [updated 2025 Jul 4; cited 2026 Oct 26]. Available from: https://www.canada.ca/en/health-canada/services/chemical-substances/challenge/batch-7/1-4-dioxane.html

[9] IARC Working Group on the Evaluation of Carcinogenic Risks to Humans. Coconut oil diethanolamine condensate. In: Some chemicals present in industrial and consumer products, food and drinking-water. Lyon (FR): International Agency for Research on Cancer; 2013. p. 141-8. (IARC Monographs on the Evaluation of Carcinogenic Risks to Humans; vol. 101). Available from: https://publications.iarc.who.int/_publications/media/download/5689/a7f9c50c94049b868c528c4f7285de11bda360b1.pdf

[10] U.S. Food and Drug Administration. Diethanolamine [Internet]. Silver Spring (MD): FDA; 2025 [cited 2026 Oct 20]. Available from: https://www.fda.gov/cosmetics/cosmetic-ingredients/diethanolamine

[11] Commission Regulation (EU) 2016/1198 of 22 July 2016 amending Annex V to Regulation (EC) No 1223/2009 of the European Parliament and of the Council on cosmetic products. OJ L 198, 2016 Jul 23, p. 10-2. Available from: https://eur-lex.europa.eu/eli/reg/2016/1198/oj/eng

[12] Scientific Committee on Consumer Safety (SCCS). Opinion on methylisothiazolinone (MI) (P94), submission III (sensitisation only). SCCS/1557/15. Brussels: European Commission; 2015 [adopted 2015 Jun 25; final version 2015 Dec 15; cited 2026 Oct 19]. Available from: https://health.ec.europa.eu/publications/methylisothiazolinone-mi-p94-submission-iii-sensitisation-only_en

[13] Scientific Committee on Consumer Safety (SCCS). Opinion on propylparaben (CAS No 94-13-3, EC No 202-307-7). SCCS/1623/20. Brussels: European Commission; 2021 [final version 2021 Mar 30-31; cited 2026 Oct 19]. Available from: https://health.ec.europa.eu/publications/propylparaben_en

[14] Scientific Committee on Consumer Safety (SCCS). Opinion on butylparaben (CAS No 94-26-8, EC No 202-318-7). SCCS/1651/23. Brussels: European Commission; 2023 [final version 2023 Oct 26; cited 2026 Oct 19]. Available from: https://health.ec.europa.eu/publications/butylparaben-cas-no-94-26-8-ec-no-202-318-7_de

[15] Health Canada. Triclosan - information sheet [Internet]. Ottawa (ON): Government of Canada; 2018 [updated 2020 Oct 10; cited 2026 Oct 26]. Available from: https://www.canada.ca/en/health-canada/services/chemical-substances/fact-sheets/chemicals-glance/triclosan.html

[16] U.S. Food and Drug Administration. Consumer antiseptic wash final rule questions and answers: guidance for industry [Internet]. Silver Spring (MD): FDA; 2017 [updated 2020 May 7; cited 2026 Oct 20]. Available from: https://www.fda.gov/regulatory-information/search-fda-guidance-documents/consumer-antiseptic-wash-final-rule-questions-and-answers

[17] Health Canada. Industry guide for the labelling of cosmetics [Internet]. Ottawa (ON): Government of Canada; 2006 [updated 2026 Apr 24; cited 2026 Oct 26]. Available from: https://www.canada.ca/en/health-canada/services/consumer-product-safety/reports-publications/industry-professionals/labelling-cosmetics.html

[18] U.S. Food and Drug Administration. Cosmetic ingredient names [Internet]. Silver Spring (MD): FDA; 2022 [cited 2026 Oct 20]. Available from: https://www.fda.gov/cosmetics/cosmetics-labeling/cosmetic-ingredient-names

[19] U.S. Food and Drug Administration. How safe are color additives? [Internet]. Silver Spring (MD): FDA; 2023 [updated 2023 Jul 13; cited 2026 Oct 20]. Available from: https://www.fda.gov/consumers/consumer-updates/how-safe-are-color-additives

[20] Environment Canada, Health Canada. Screening assessment for the Challenge: decamethylcyclopentasiloxane (D5), Chemical Abstracts Service Registry Number 541-02-6 [Internet]. Ottawa (ON): Government of Canada; 2008 Nov [cited 2026 Oct 26]. Available from: https://www.canada.ca/en/environment-climate-change/services/evaluating-existing-substances/screening-assessment-forchallenge60.html

[21] U.S. Food and Drug Administration. Fragrances in cosmetics [Internet]. Silver Spring (MD): FDA; 2022 [cited 2026 Oct 20]. Available from: https://www.fda.gov/cosmetics/cosmetic-ingredients/fragrances-cosmetics

[22] Environmental Working Group. Discover EWG VERIFIED® [Internet]. Washington (DC): EWG; 2026 [cited 2026 Oct 20]. Available from: https://www.ewg.org/skindeep/ewgverified

[23] Scientific Committee on Consumer Safety (SCCS). Opinion on fragrance allergens in cosmetic products. SCCS/1459/11. Brussels: European Commission; 2012 [adopted 2012 Jun 26-27; cited 2026 Oct 26]. Available from: https://ec.europa.eu/health/scientific_committees/consumer_safety/docs/sccs_o_102.pdf

[24] Scientific Committee on Consumer Safety (SCCS). Allergenic fragrances in cosmetic products: citizens’ summary [Internet]. Brussels: European Commission; [cited 2026 Oct 19]. Available from: https://ec.europa.eu/health/scientific_committees/opinions_layman/perfume-allergies/en/citizens-summary-allergens.pdf

[25] International Organization for Standardization. ISO 16128-1:2016. Guidelines on technical definitions and criteria for natural and organic cosmetic ingredients and products — Part 1: Definitions for ingredients [Internet]. Geneva: ISO; 2016 [cited 2026 Oct 26]. Available from: https://www.iso.org/standard/62503.html

Written by Team ATTITUDE