# skin deodorant based on zinc soaps



## Robert (Sep 14, 2013)

Just came across an interesting expired patent for this stuff.  The material used for the great majority of the formulas therein could easily be made by soap hobbyists, although a few of the substances would be beyond most.  Mostly they're made of zinc soap of castor oil, made by saponifying castor oil as usual and then mixing a solution of the soap with a zinc salt and recovering the solid zinc soap.  (Zinc hydroxide's not alkaline enough to directly saponify with by normal or convenient means, sorry.)

It's said to work on other potentially stinky things too, like cat litter, but it should be tolerated well by skin too, especially considering that other zinc compounds are in use on skin as sun blocks and baby powders or creams.  I don't know how many of you would want to try the permanganate oxid'n to make the "booster" substances, though, but they don't seem from the patent description to be essential for the major effect.


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## Evik (Oct 3, 2013)

Hi Robert, 

You do not need to make a soap based zinc deodorant. I have been using one for 2 years, which I made after I found a scientific article showing that zinc oxide itself is a perfect deodorant for stinky feet - even better than aluminium-based ones. I have made quite a research on the subject and discuss that in my blog pretty in detail here:
http://curious-soapmaker.com/zinc-oxide-use-natural-deodorants.html
 
and here is the recipe:

http://curious-soapmaker.com/natural-cream-deodorant-that-really_6.html


Basically, any zinc oxide cream works as a deodorant (I put in mine 30% of zinc oxide).


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## Robert (Oct 3, 2013)

Evik said:


> You do not need to make a soap based zinc deodorant. I have been using one for 2 years, which I made after I found a scientific article showing that zinc oxide itself is a perfect deodorant for stinky feet - even better than aluminium-based ones. I have made quite a research on the subject and discuss that in my blog pretty in detail here:
> curious-soapmaker.com/zinc-oxide-use-natural-deodorants.html
> 
> and here is the recipe:
> ...


The 1st link isn't working, although the 2nd sure is.  I'm glad this works for you, and I bet it's also better tolerated by skin than aluminum-based and other products are.  However, there is one advantage to making a Zn soap, and that is it might be easier to make & keep than a zinc oxide cream, unless you already have an emulsified and preserved base made up.  The soap would not be a kind you could wash with, but would be to rub onto dry skin.  I don't think I made that clear before--that I'm using the word "soap" in a chemical sense, and not in the looser, colloquial sense of "detergent" or "something to wash with".


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## Evik (Oct 3, 2013)

Hi Robert, 

sorry for the link, the http:// was missing, now corrected. I understood what you meant by soap and now I see your point of view. I make creams from scratch and it is not a problem for me to make one. However, you don't really need to make one, you can simply buy a diaper rash cream or sunscreen with high percentage of zinc oxide, or add zinc oxide to an existing cream or lotion.

I can understand you prefer a stick deodorant. When I look at the patent, I find the process of making zinc ricinoleate quite complex, but why not, given the fact you can easily find zinc sulphate heptahydrate (which I am not sure is available for home soapmakers easily). Maybe less difficult would be to add the zinc oxide into a classic CP soap in high quantity?

In the zinc soap deodorant as described by the patent, I would also fear that it won't be efficient enough in skin applications (where no water is used to remove it after use). The reason is that zinc oxide is reacting with decomposed fatty acids that are made by bacteria from skin sebum oils, creating non smelly zinc soaps. If you apply already zinc salts on your skin in, I suppose it won't be that efficient,although it can be good in picking up other odor causing compounds (as described in the patent).

It would be nice to compare that...


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## Robert (Oct 4, 2013)

Evik said:


> sorry for the link, the http:// was missing, now corrected.


Actually I tried supplying the http:// myself, still didn't work.


> I understood what you meant by soap


I didn't mean to imply you didn't, I'm just always thinking of others who may read the thread now or later.


> I make creams from scratch and it is not a problem for me to make one. However, you don't really need to make one, you can simply buy a diaper rash cream or sunscreen with high percentage of zinc oxide, or add zinc oxide to an existing cream or lotion.


Aw, but that's no fun.


> I can understand you prefer a stick deodorant.


I wasn't thinking of myself, just that a lot of hobbyists are after a vehicle like that.


> When I look at the patent, I find the process of making zinc ricinoleate quite complex, but why not, given the fact you can easily find zinc sulphate heptahydrate (which I am not sure is available for home soapmakers easily). Maybe less difficult would be to add the zinc oxide into a classic CP soap in high quantity?


The patent claimed that some of the effectiveness came from the zinc, and some from particular soap embodiments like that.  I think most DIYers would use a simpler soap than that.


> In the zinc soap deodorant as described by the patent, I would also fear that it won't be efficient enough in skin applications (where no water is used to remove it after use). The reason is that zinc oxide is reacting with decomposed fatty acids that are made by bacteria from skin sebum oils, creating non smelly zinc soaps. If you apply already zinc salts on your skin in, I suppose it won't be that efficient,although it can be good in picking up other odor causing compounds (as described in the patent).
> 
> It would be nice to compare that...


It would be.  I don't think most of the effect comes from a simple acid-base rxn like that, but rather some way that the Zn acts greater than stoichiometrically, such as by inhibiting other rxns.


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