Hello dear Migglers!

I saw another disturbing report on NDR at the weekend. It was about polyquaternium-7, a plastic found in most shower gels and shampoos. Personally, I don't want to shower with it, not just for my own sake, but also for the sake of the water.

So, off to Migros to read the bottle. I could only find one shower gel without this additive (Rexona). Wouldn't Migros like to take on a pioneering role for once and do without such nonsense?


Caution: Stains from shower gel?

Following a tip from a viewer, we tried the process ourselves and washed clothes stained with shower gel in the washing machine. The result: Wherever the shower gel came into contact with the laundry, there were dark stains that did not lighten even after a second wash. A laundry tried to remove the stains, but even the harshest bleach couldn't get rid of them.

Cause: a plastic in the shower gel
The head of the laundry, Uwe Riedel, then found a reference to polyquaternium-7 on the shower gel packaging and explained: "It's a plastic and, in combination with the detergent solution, it practically acts like a two-component adhesive." Polyquaternium-7 is a declarable substance, which means that it must be indicated on the packaging.

What exactly is polyquaternium-7?
We take a random sample and buy 19 shampoos and 19 shower gels in a drugstore. We found polyquaternium-7 in four shampoos and eleven shower gels. Polyquaternium-7 is a so-called film former, it is supposed to coat the hair with a protective film and make it easier to comb and antistatic. Polyquaternium is a polymer, i.e. a plastic. This plastic is positively charged and therefore adheres particularly well to hair, which has a strong negative charge.

That is the problem. Similar to hair, polyquaternium-7 also sticks to laundry. What's more, the suds are also negatively charged and this strengthens the bond on the fabrics. At the same time, polyquaternium-7 attracts color pigments from the suds and binds them permanently. This effect continues even after subsequent washes. For example, stains may not appear on towels that come into contact with polyquaternium until a few washes later. This is when there is a lot of dirt and color pigments in the washing solution.

Industry reaction
We contacted the German Association of Personal Care and Detergents and asked why no warning about staining was printed on the products. The association's answer: "When used properly, a shower gel does not come into contact with textiles." The industry therefore believes that the stains on the laundry are caused by user error, so to speak.

Stains even with normal use
Interestingly, polyquaternium-7 is much more common in shower gels than in shampoos. In these cases, however, the plastic should also form a film on the skin. We try it out: We wash our hands and arms ten times with a normal soap and use a white towel. Then we use a shower gel containing polyquaternium-7 instead of soap. Again, we dry off with a white towel. We put both towels in the washing machine together with a pair of new jeans. The result is clear. The towel from the polyquaternium hand wash has dark stains. It has rubbed the polyquaternium film off the skin and the color pigments in the jeans have made this polyquaternium-7 visible.

It seems illogical that the industry uses the hair straightener polyquaternium-7 more often in shower gels than in shampoos. However, the body care and detergent industry association sees the substance as multifunctional: "In hair care products, it ensures better combability, while in shower gels, for example, it makes the skin feel better."

We take a closer look at polyquaternium-7: The plastic that triggers this great skin feeling has a toxic substance in it that is otherwise found in chips, cookies and potato chips: acrylamide. Is there a link between polyquaternium and acrylamide? In fact, the German Federal Office for Risk Assessment warned against polyquaternium-7 as a source of acrylamide as early as 2003.

Polyquaternium-7 as a substance is contaminated with acrylamide. This contamination occurs during the production process in oil refineries. If the substances get into the wastewater after showering and washing hair, the sewage treatment plants have difficulties with them. This is because polyquaternium-7 is not biodegradable and acrylamide is poison for the beneficial bacteria in the sewage basin, explains Harald Hanßen, a graduate engineer at Hamburg Wasser's sewage treatment plant: "They impair the utilization of the waste we produce during wastewater treatment."

To put this into perspective: with every bag of potato chips we ingest many times more acrylamide than after weeks of showering with a shower gel containing polyquaternium 7. In addition, there are limits for polyquaternium-7 as to how much acrylamide the substance may contain.

The industry sticks to polyquaternium-7
Nevertheless, the question remains as to why the industry does not abandon this problematic substance, especially as there are acrylamide-free alternatives such as silicones or chitosan. The answer: "There is no reason to do so. Cosmetics are safe and pose no health risks." Cosmetics manufacturers are determined to hold on to this problematic substance because polyquaternium-7 is unbeatably cheap. A metric ton, or 1,000 kilograms, costs 800 to 850 dollars in China. This means that one kilogram of this active ingredient costs less than 70 cents in the eurozone. The alternatives are many times more expensive.