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Quaternary Ammonium Compounds

Called "quats" for short, quaternary ammonium compounds are used commonly in hair conditioners, shampoos, and even lotions, to impart a slippery feel to the hair and skin. Quats are the chemicals that enable you to have a little dollop of conditioner and let it easily glide and be distributed throughout your hair. They also have anti-microbial properties and are commonly used as preservatives. There are a number of problems with quats, however. First, they are known to cause skin and respiratory irritation, and some people are highly allergic to them. Second, some quaternary ammonium compounds, like benzalkonium chloride, are phenolic and have been found to be endocrine disruptors, meaning they interfere with hormone function within the body. Third, they are toxic to aquatic life, so they're not good for the environment when washed downstream.

Some examples of quaternary ammonium compounds:

babassuamidopropalkonium chloride
benzalkonium chloride
benzathonium chloride
Grapefruit Seed Extract
methylbenzethonium chloride
cetalkonium chloride
Vegetable Oil Quaternary
stearalkonium chloride
guar hydroxypropyltrimonium chloride
behentrimonium chloride
behentrimonium methosulfate

Check out what this chemical safety database says about quats:

"Quaternary ammonium compounds can cause toxic effects by all routes of exposure including inhalation, ingestion,dermal application and irrigation of body cavities. Exposure to diluted solutions can cause mild and self-limited irritation. Concentrated solutions of quaternary ammonium compounds are corrosive and can cause burns to the skin and the mucous membranes. They can produce systemic toxicity due to their curare-like properties. They can also cause allergic reactions.

Mild to severe caustic burns of the skin and mucous membranes can occur depending on the agent and the concentration. Other signs may include: nausea, vomiting, abdominal pain, anxiety, restlessness, coma, convulsions, hypotension, cyanosis and apnoea due to respiratory muscle paralysis; death may occur within 1 or 3 hours after ingestion of concentrated solutions. Haemolysis and methaemoglobinemia have been reported infrequently."

Here is a report that the SCCS (Scientific Committee on Consumer Safety, an organization in the EU) did on a number of quats. The SCCS recommends that based on the skin reactions and toxicity seen in the studies, that concentrations of behentrimonium chloride shouldn't exceed 3% in a rinse-off product, and should be no more than .5% in a leave-on product.

Reader Comments (10)

This is disturbing as it is so widely used in food service as a dish sanitizer! It is used in the kitchen where I work. I guess we'll have to wear gloves and a mask.

Tue, July 31, 2012 | Unregistered Commenterartizan

It's nice to know what such chemicals can do to us. It would be the responsibility of the user on how to use it correctly.

Sun, June 9, 2013 | Unregistered Commenteraileen eva

My 84 year old mother-in-law has been having sudden unexplained seizure like activity and near loss of consciousness. I found my husband cleaning her bedside commode with a natural supposedly healthy toilet bowl cleaner and right afterward she had a seizure episode. Upon investigation I found one of the ingredients is a quaternary ammonia. Your article was very helpful. I think she is very sensitive to inhaled quats. A quaternary disinfectant gave me two autoimmune skin conditions after I was exposed to them repeatedly as a nurse on the job for four years in a hospital setting.

Fri, August 30, 2013 | Unregistered CommenterRZimm

Nice post ... good to know such things about Quaternary Ammonium Compounds

Wed, October 23, 2013 | Unregistered CommenterAcetate

Do not forget acquired resistance, that are cross to other antibotics!

Sat, November 23, 2013 | Unregistered CommenterMiroslav Besermenji


Have their been studies of how quats react to silicones, poly-acrylates and PVCs? I theorize the quats are causing polymeric degradation when combined with an organic solvent such as IPA, EtOH or MeOH??

Mike Gruenhagen

Fri, November 20, 2015 | Unregistered CommenterMikeG

Interesting. I had allergic reaction to a disinfectant that had this in it. supposed to be a medical disinfectant but was poured inside a pipe crawlspace inside my apartment for mold. Does this thing ever degrade or is it active forever?

Also, i've read that quaternary ammonium chloride can be a breakdown product in polypropeline. Does anyone know if that all can apply to 24 hour urine containers that have preservatives in them? had very bad allergic reaction and burnt lips from that; don't think it was the preservative itself since i smelled the same substance on a new container with a different preservative than the first. . unless the preservatives break down the plastic in some way?

Mon, January 11, 2016 | Unregistered CommenterTooManyChemicals

Thanks for posting this. I have had three allergic reactions eating at three different places on campus and finally found out that they use this sanitizer in all their kitchens. They sanitize counters, cutting boards and knives with it - in order to avoid cross contamination of food! Thanks a lot University.

Fri, July 8, 2016 | Unregistered CommenterFlorence

Why do you list grapefruit seed extract as a quat? As far as I know it is natural... :-/

Wed, November 22, 2017 | Unregistered CommenterKaren

I too am interested in grapefruitseed extract. It's sold ad a health product.

Sun, February 24, 2019 | Unregistered CommenterSusanna

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