Cetrimonium chloride

cetrimonium-chloride

Cetrimonium Chloride is the mainstay of hair conditioners. It works in a very simple way. Damaged hair has an electric charge. This is why you get flyway hair. The hair shafts are literally repelling one another. Conditioners work by neutralising that charge and replacing it with a lubricious layer of loveliness. 

Let’s have a look at the details. The very top layer of the hair shaft is protected by tiny plates. These are hard and shiny and have a very slight positive charge.  When these plates are in good condition, your hair is in good condition.  It shines and the very slight surface charge means that hair shafts repel one another so the hairs don’t stick to each other and glide smoothly when combed.  This is what most of us want from our hair most of the time. When the plates get damaged or even lost altogether, the situation is very different.  The hair below the plates has a dull appearance.  And even worse, it has a strong negative charge.  The very slight mutual repulsion that is beneficial in hair that is in good condition becomes an extreme force pushing the hair shafts away.   This creates the unmanageable fly away hair that in some extreme cases even sticks up.  So your hair is now not smooth, shiny and able to glide along the comb.   It is dull, fractious and gives every indication of having a mind of its own.  And that mind is a malicious one.

cetrimonium-chloride

Cetrimonium chloride has a positive charge at one end of a long carbon chain

So what to do?

One option is to crack open a bottle of conditioner.  This is where the cetrimonium chloride comes in.   It is what is called a quaternary ammonium compound, and the significance of this is that it is a long molecule with a large positive charge at one end.  This positive charge is attracted to the negative charge on the damaged hair shaft.  So what happens is that the cetrimonium chloride attaches itself to the hair coating the damaged bits.  Hey presto, your hair is no longer fly away and you can now do something with it.

The ability of cetrimonium chloride to seek out damaged hair and fix it has been used in the past by marketers.  I remember working on one conditioner that went under the tag line ‘conditions your hair only where it is needed’.  This was perfectly true, though a rather strange way to put it.  It was like saying that soap washes your hand only where it is dirty.  But I suppose I shouldn’t complain about advertising that is justified when you think about how much is pure moonshine.

Cetrimonium chloride is still the most widely used quaternary ammonium compound in hair conditioners, but there is a whole family of them that work in much the same way.  They usually have the -ium bit in the name somewhere and often chloride too, but bromide sometimes pops up.  There are conditioning agents that aren’t related but these tend to be used in combination with something like cetrimonium chloride.  I hope this gives you something to think about while your hair is drying.

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Safety information and other boring stuff about cetrimonium chloride can be found on the cosmetics info database.

If you like ingredient posts, here are three of my most popular ones.

Cetearyl alcohol

Potassium sorbate

Mineral oil

And there is a full list on my cosmetics ingredient database page.

 

8 thoughts on “Cetrimonium chloride

  1. Aesthete

    Hi Colin,

    Thank you breaking down Cetrimonium chloride. I’ve seen it in shampoo also. Does it work better in shampoo or conditioner? How much of it (%) would a product need or where abouts it should be on the ingredient list to have the effect you describe?

    Thanks in advance!

  2. Colin

    Hi Aesthete, sorry to have taken so long to reply. Quaternary compounds in general including cetrimonium chloride don’t work at all well with shampoos. The quats are positively charged and shampoos are full of negatively charged surfactant ions. These stop them from working at all.

  3. Aine

    Great article, Colin. I’m sure I’ve read it before but I really enjoyed it this time round. Very informative, easy for science idiots like me to understand, and I laughed out loud a few times. Thank you.

  4. Kelli

    Hi Colin. I wanted to ask if you have any information about Cetrimonium Bromide and how it benefits hair? Any information would be greatly appreciated.
    Thanks,
    Kelli

  5. Colin Post author

    Hi Kelli,

    I don’t think that the use of bromide rather than chloride makes any difference- though I have never done a side by side comparison. I think someone once told me that the bromide was more effective as an antiseptic, but I have been told lots of things like that over the years and they turn out to be false as often as they are true. But even if true, it doesn’t relate to its use in hair care.

  6. Ayanda

    Hi Colin,

    I’ve read conflicting information about the maximum allowable concentration of cetrimonium chloride for leave in and rinse off products in the EU, do you know what they are or a reliable source I could use to find out?

    Many thanks
    Ayanda

  7. Colin Post author

    You’ll find all the restrictions in Annex III of the cosmetic regulations.

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