Harmful Ingredients in Shampoo

woman with long hair in black and white

Did you know that there are harmful ingredients in shampoo?  There are known and suspected allergens, irritants, and toxins lurking in many personal care and beauty products that may grace your bathroom shelves.

Sounds kind of crazy, right?

Known and suspected toxins.  No way?!

The trouble with the cosmetics industry is that the regulations for personal care products (things like shampoo) are incredibly loose.  

In North America, and in many other countries worldwide, the burden of proof is on the consumer.  That means that ingredients are considered safe until proven harmful.  

And it is not in a company's interest to prove their ingredients harmful.

And so many ingredients like parabens, SLS, and others, are used in personal care products for years until enough third-party evidence is accumulated to have an ingredient banned.

[Triclosan, an antibacterial agent used in many hand soaps and sanitizers, was actually just banned in the summer of 2016 in Canada.]

So how do you avoid harmful ingredients in shampoo?  

You have 3 options:

1. Learn to read your labels.  (The 6 most harmful ingredients in shampoo can be found below.)  

2. Buy a product that you know is safe.  Going certified organic is a good way to avoid all the synthetic irritants and toxins without becoming an expert in label-reading.

You can find my favourite food-grade certified organic products here.

3. Make your own shampoo.  You can get your hands on my favourite (an super simple) all natural DIY shampoo bar recipe here.

6 Most Harmful Ingredients in Shampoo & How to Avoid Them

Below are the 6 most harmful ingredients in shampoo.  Check your bottles and make sure you are not using any of these offenders.

Sodium Laureth Sulfate (SLS or SLES)

Sodium laureth sulfate (SLS) is a foaming agent found in many body washes, bubble baths, shampoos, and basically anything that foams.

The problem with SLS is that it is harsh on the skin.  In order to make it gentler, companies will ethoxylate it, which turns it into SLES.  SLES can be contaminated with 1,4-dioxane, a probably human carcinogen (i.e. it likely causes cancer).

Fragrance or Parfum

"Fragrance" is considered a trade secret in the cosmetics industry, and so companies don't have to disclose what exactly is in their fragrance.  Over 3,000 different chemicals may be hidden by the word "fragrance". This is problem #1.

Problem #2 is that  “fragrance” or “parfum” also usually signals the presence of phthalates and toulene.  Phthalates are suspected endocrine disrupters, which can have adverse developmental, reproductive, neurological, and immune effects.  One phthalate in particular, DEHP is a possible source of cancer.

Toulene  can cause liver, kidney, and brain damage as well as damage to a developing foetus.

PEG Compounds

PEG compounds are petroleum-based chemicals that are often used in cosmetics as  thickeners, solvents, softeners, and moisture-carriers.  

They can be contaminated with ethylene oxide (a known human carcinogen) and 1,4-dioxane (a suspected human carcinogen). 1,4-dioxane is also a suspected kidney toxicant, neurotoxicant, and respiratory toxicant.


Parabens are commonly used in shampoo as a preservative.

The problem with parabens is that they are suspected endocrine disruptors and may cause cancer.

The European Commission on Endocrine Disruption has listed parabens as Category 1 priority substances, based on evidence that they interfere with hormone function.

Parabens have been detected in human breast cancer tissues, suggesting a possible association between parabens in cosmetics and cancer.

Parabens may also interfere with male reproductive functions.


Quaternium-15 is a preservative sometimes used in shampoo that slowly releases formaldehyde, a known carcinogen (i.e. this does cause cancer).

Quaternium-15 can also irritate the skin and eyes and trigger allergies at low doses.

Cocamidopropyl Betaine

Cocamidopropyl betaine is a chemical used in products like shampoo, toothpaste, and body wash.  It is derived from coconuts, and its primary purpose is to make your product foamy.

Cocamidopropyl betaine can cause allergic reactions and skin and eye irritations.  

The biggest danger of using a product with cocamidopropyl betaine is its potential contamination with nitrosamines, which have been identified as one of the most potent classes of carcinogens, having caused cancer in more than 40 different animal species as well as in humans.

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2 Comment

  1. Ericka Mbl says: Reply

    This is alarming! As it is possible that this type of products come to the market causing so much damage to humanity and is so allowed that few people know this important information not only feed us with hormones and insecticides but put chemicals in products that harm our health .

    Thanks for the information I will be more careful when buying any shampoo in the market making it organic and if it is better I will do it myself as I have learned here.

    1. Rebecca says: Reply

      Yes, Ericka, choosing organic is a good option. BTW, make sure that it’s certified organic by a third party body: the ACO and the USDA have some of the highest standards worldwide. Just picking something that says “organic” doesn’t actually gaurantee that this junk isn’t in the product. You have to read the labels or pick something that’s certified.

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