Teach Soap

I was reading the ingredients on a bottle of BBW lotion I have and one of the ingredients listed was Sodium Hydroxide???? Why is that in there????

To adjust the ph.

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Genny

Yes. Genny beat me to it. It's in toothpaste too and pretzels and pickles.

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Irena
Closed minds are like faulty parachutes; they refuse to open.

And a lot of shampoo. I've been reading a lot of labels now that I have a better idea of what ingredients do what.

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~~Heather~~
Mad [soaping] Scientist

potassium hydroxide, sodium hydroxide, and TEA (triethanolamine) are all used to raise pH.
citric acid is the usual thing to lower pH.
I personally prefer not to use TEA because of the possibility of nitrosamines, which are carcinogenic. Unfortunately, if you want to make transparent gels then you usually have to use TEA.
Talking of labels, I was just examining the label on a bottle of Org@^ix hair conditioner, an expensive brand. It has 26 ingredients, including d-Limonene. Cannot imagine why that should be in a conditioner. There were at least 5 separate preservatives, giving me the impression that they thought: umm, maybe one or two of these really don't work too well, but not sure really, so, umm, let's add some of this... and how about, yes, some of this and this too... that should do it
Having said that, it is pretty nice. It has a lot of silicone in it though. I experimented a little and was able to almost exactly duplicate the fragrance, using a combination of 0.5% vanilla oil and 1% vanilla/lavender FO.

Interesting. So in small amounts its not caustic then?

If you add NaOH to raise the pH what happens is it reacts with something. You don't end up with actual NaOH in the product. For instance lets say I have a fruity product that contains acids such as tartaric, citric etc. If I add sodium hydroxide I'll get a reaction like:
sodium hydroxide + citric acid -> sodium citrate + water
or
sodium hydroxide + tartaric acid -> sodium tartrate + water
and even if there are no free acids but only oils and butters, well, they are acids too; so:
sodium hydroxide + palmitic acid -> sodium palmitate + water