Check your dishwashing soap for allergenic preservatives

4. apr 2017

Dishwashing liquids found in Danish shops are often good choices without problematic chemicals. But a test from The Danish Consumer Council THINK Chemicals shows that one in three products in the test contains allergenic preservatives.


Test of chemicals in dishwashing soap
Photo: Nikoline Oturai

Dishwashing liquids: Free from endocrine disruptors

33 soaps for washing dishes by hand have been checked for problematic chemicals.

As detergents do not have to list all ingredients on the label, the chemical content of the products have been found in the detergent datasheets that includes all ingredients. The detergent datasheet has to be available on the website that is listed on the product.

The ingredients have been checked for suspected endocrine disruptors, sensitizing substances and chemicals with other problematic effects.

The test shows that you do not need to worry about endocrine disruptors in your dishwashing soap. But it is relevant to consider sensitizing preservatives and perfume.

  • 14 dishwashing liquids are free from problematic chemicals
  • 6 dishwashing liquids are free from problematic chemicals but contain perfume
  • 13 dishwashing liquids contain sensitizing preservatives

See the test results (in Danish).

12 dishwashing soaps contain Methylisothiazolinone

Methylisothiazolinone (MI) is a highly sensitizing preservative used in many different products, such as paint, cosmetics and detergents. MI was used in 12 of the 13 dishwashing soaps that contained sensitizing preservatives.

Each year more than 1.000 Danes are diagnosed with contact dermatitis related to MI. Because of this, it is a good idea to minimize the exposure to MI in order to lower the risk of being sensitized.

The substances Benzisothiazolinone and Octylisothiazolinone were also found. They are similar to MI.

Sensitizing preservatives

These are the findings of sensitizing preservatives/antioxidants in the test:

  • Methylisothiazolinone in 12 products
  • Benzisothiazolinone in 9 products
  • Octylisothiazolinone in 1 product
  • Propyl gallate i 2 products
  • Glutaral i 1 product

Difficult to obtain full information on ingredients

Diswashing soaps have to have a website listed on the product, where the consumers can find a full list on ingredients (datasheet). The label of the product does not need to declare all ingredients.

The test showed that these lists can be difficult to obtain. We found examples of missing lists, lists that were extremely difficult to find and lists that were outdated. Our first try gave correct information on 9 products, faulty information on 10 products and no data on 14 products. Some of the ingredients lists were found with help from the companies and other companies had the datasheets made on our request.

Faulty claims on products

I the test we also found examples of claims that could mislead the consumers. Among others two companies wrote “aloe vera” on their products, even though the products did not contain any aloe vera.

Another product claimed “sensitive”, even though it contained the highly sensitizing substance Methylisothiazolinone. Two of the companies have afterwards decided to change their products.

For further questions about the test contact Christel Søgaard Kirkeby, project manager in The Danish Consumer Council THINK Chemicals, on e-mail