Sodium Hydroxide in Lotion?

[MissE]

My first real-life contact with sodium hydroxide came from soapmaking. Imagine my surprise when I saw sodium hydroxide on the label while shopping for a lotion/cream for the season yesterday. I grabbed a few more at random and scrutinized the labels, and sure enough sodium hydroxide showed up quite a bit. I didn't know they added tthat to lotions and creams!

Question, what might be the function of sodium hydroxide in a lotion?

 

[DeeAnna]

It's used to adjust the pH of the product to keep it within proper limits. No big deal.

 

[toxikon]

Susan has a little blurb about it here! :mrgreen:

http://swiftcraftymonkey.blogspot.ca/2014/01/weekend-wonderings-are-bath-melts-safe.html

WHY WOULD WE FIND SODIUM HYDROXIDE IN A LOTION?
Rosi asks: I have some body lotion from the store and there is sodium hydroxide on the ingredient list, what does it bring to the lotion?

Sodium hydroxide could do one of three things in a lotion...
1. It could help the carbomer turn into a gel;
2. It could be helping adjust the pH to a more alkaline one; or
3. It could be turning something into a soap to behave as an emulsifier.

To turn a carbomer turn into a gel, we use an alkaline ingredient - in this case it would be something like an 18% solution of sodium hydroxide - to turn it from the flaky gel stuff into the gooey gel stuff. To adjust the pH, we would use a dilute solution of sodium hydroxide to raise the pH to become more alkaline. To use it as a soap as an emulsifier, we would be turning an oil or triglyceride into a soap through the process of saponification. (I know very little about this concept, to be honest...)

 

[jcandleattic]

Once you start recognizing ingredients, you will notice them in a lot of stuff. Especially NaOH. I never realized until after making soap that NaOH is an ingredient in pretzels and other types of Irish and German breads (and probably other nationalities as well).

 

[Dahila]

Buffering solution in lotions

 

[DeeAnna]

With respect, NaOH is not a buffer, Dahlia. It is a strong base and dissociates almost completely. A buffer (like soap) by definition does not dissociate (break apart) easily.

 

[MissE]

Thanks, everyone, for weighing in.

 

[SunRiseArts]

Once you start recognizing ingredients, you will notice them in a lot of stuff. Especially NaOH. I never realized until after making soap that NaOH is an ingredient in pretzels and other types of Irish and German breads (and probably other nationalities as well).

when I learned that I was thinking the acids in out digestive system must be so strong. :shock:

 

[Dahila]

With respect, NaOH is not a buffer, Dahlia. It is a strong base and dissociates almost completely. A buffer (like soap) by definition does not dissociate (break apart) easily.

People do call it that. I use it to higher ph in lotions when it goes to low.
Thanks DeeAnna, so what is the proper name for this solution?
it is 10% Naoh and 90 Water

 

[lenarenee]

I once freaked when reading the label of a whitening toothpaste....LYE??? :shock:
.

 

[chela1261]

A couple of weeks ago I bought a hand cream and was totally surprised to see sodium hydroxide in it. I had no idea they used it in lotions, creams etc or why

 

[dixiedragon]

Once you start recognizing ingredients, you will notice them in a lot of stuff. Especially NaOH. I never realized until after making soap that NaOH is an ingredient in pretzels and other types of Irish and German breads (and probably other nationalities as well).

Bagels too. That's why we sometimes see lye that is labeled "food grade".

https://www.npr.org/sections/thesal...pretzel-crust-count-on-chemistry-and-memories

 

[DeeAnna]

People do call it that. I use it to higher ph in lotions when it goes to low.
Thanks DeeAnna, so what is the proper name for this solution?
it is 10% Naoh and 90 Water

I'd call it a sodium hydroxide solution. It doesn't have any fancy name that I'm aware of.

If people are calling sodium hydroxide solution a "buffer," they're mistaken. NaOH can be used to raise the pH, yes, but simple pH adjustment is different than adding a buffer to help stabilize the pH. There are many chemicals that could be used in a lotion to buffer the pH, but NaOH is not one of them.

 

[Dahila]

I'd call it a sodium hydroxide solution. It doesn't have any fancy name that I'm aware of.

If people are calling sodium hydroxide solution a "buffer," they're mistaken. NaOH can be used to raise the pH, yes, but simple pH adjustment is different than adding a buffer to help stabilize the pH. There are many chemicals that could be used in a lotion to buffer the pH, but NaOH is not one of them.

thank you so much, someone was correcting me in the group that is not naoh solution but 'buffer solution", I do believe in you DeeAnna you never give out wrong information. Thank you so much

 

[DeeAnna]

Hmmm. I'm puzzled. I guess I'd have to read the actual discussion to get a better sense of why they're saying NaOH is a buffer. It doesn't make a lot of sense to me at this point, but I suppose I might be missing something.

 

[MissE]

Susan has a little blurb about it here! :mrgreen:

http://swiftcraftymonkey.blogspot.ca/2014/01/weekend-wonderings-are-bath-melts-safe.html

Referring to (3), does it mean there is some amount of the lotion that is actually soap?

Bagels too. That's why we sometimes see lye that is labeled "food grade".

https://www.npr.org/sections/thesal...pretzel-crust-count-on-chemistry-and-memories

I've wondered about the 'food grade' lye, too, is it different than the one we use for soapmaking?

 

[jcandleattic]

I've wondered about the 'food grade' lye, too, is it different than the one we use for soapmaking?

You can use food grade in soapmaking. It's not different, it's just processed differently so more impurities are taken out. I actually prefer it for soapmaking.

 

[MissE]

You can use food grade in soapmaking. It's not different, it's just processed differently so more impurities are taken out. I actually prefer it for soapmaking.

Thanks, jcandleattic.

 

[DeeAnna]

Food grade NaOH may not be any different than the non-food grade except for the degree of laboratory testing. Food grade has to meet more stringent standards for certain types of contaminants such as mercury, but it's made in the same equipment and with the same chemical process as tech grade. It's just one day they test to tech grade standards and the next day the test is to food grade standards.

 

[MissE]

Food grade NaOH may not be any different than the non-food grade except for the degree of laboratory testing. Food grade has to meet more stringent standards for certain types of contaminants such as mercury, but it's made in the same equipment and with the same chemical process as tech grade. It's just one day they test to tech grade standards and the next day the test is to food grade standards.

Thanks, DeeAnna. I have to wonder, does going for and using food-grade lye specifically not mean that the soap produced is that much safer for the skin? I would certainly want to avoid mercury ending up in my soap.

And is food-grade lye more expensive generally than the tech-grade one, or more difficult to find, or what?