What Do the Ingredients on a Soap Label Mean?
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Have you ever turned over a simple bar of soap and found an ingredient list that doesn't look simple at all?
Aqua. Sodium olivate. Sodium cocoate. Sodium chloride. Glycerin.
They may sound like complicated chemicals, but some of these names describe very familiar things — water, salt, oils that have been turned into soap, and glycerin.
Let's decode a traditional soap label.
Aqua
Aqua simply means water.
You may see aqua instead of water on soaps that use international cosmetic ingredient naming.
Water plays an important role in soapmaking because the alkali used to make soap is typically dissolved in water before it is combined with oils.
Much of that water can evaporate as a bar dries and ages, but some water remains in the finished soap.
Sodium Olivate
This one sounds much more mysterious than it is.
Sodium olivate is the name used for saponified olive oil — in other words, olive oil that has reacted with sodium hydroxide to become soap.
You'll see similar names depending on which oils were used:
Sodium cocoate — derived from coconut oil
Sodium palmate — derived from palm oil
The word sodium is a clue that sodium hydroxide was the alkali involved in making these hard soaps.
What About Potassium?
Sometimes you'll see potassium instead of sodium.
Potassium hydroxide is another alkali used in soapmaking and is commonly used for softer and liquid soaps, while sodium hydroxide is typically used for hard bar soaps.
So you might encounter names such as potassium olivate or potassium cocoate.
Again, these complicated-looking names can simply be describing oils that have been turned into soap.
Sodium Chloride
Here's an especially easy one:
Sodium chloride is salt.
Salt has a long history in traditional soapmaking. In some methods, it is added to help separate the newly formed soap from the watery mixture — a process known as salting out.
Depending on the soapmaking method and formulation, salt can serve other purposes as well.
So seeing sodium chloride on a soap label doesn't mean there's an exotic chemical in the bar.
It may simply mean salt.
Glycerin
Glycerin is particularly interesting because it doesn't necessarily have to be added to soap.
Glycerin is naturally created during saponification.
When fats or oils react with an alkali, the reaction produces soap along with glycerin.
What happens to that glycerin depends on the soapmaking process. In some traditional processes, much of it can be separated from the soap along with the watery portion of the mixture. In other methods, the naturally produced glycerin remains in the finished bar.
So when you see glycerin on an ingredient list, don't automatically assume that the maker poured glycerin into the recipe as a separate additive.
It may have been created while the soap itself was being made.
Sodium Hydroxide and Potassium Hydroxide
These are the alkalis — or lyes — used to make soap.
Sodium hydroxide is generally used for hard bar soap.
Potassium hydroxide is commonly used for softer or liquid soap.
If you see one of these on an ingredient list, it may be because the maker is listing the ingredients used to make the soap, rather than describing only what is present after saponification.
During saponification, the alkali reacts with the oils to form soap.
Why Can Two Similar Soaps Have Very Different Ingredient Lists?
This is where soap labels can be confusing.
One label might say:
Olive oil, water, sodium hydroxide
while another might say:
Sodium olivate, aqua, glycerin
Those lists look quite different, but they can reflect closely related soapmaking chemistry described in different ways.
That's why reading a traditional soap label isn't always as simple as counting the number of ingredients or deciding that the most scientific-looking names must be additives.
Sometimes the unfamiliar word is simply the technical name for something very familiar.
Soap School Fact
Sodium chloride is salt. Aqua is water. And sodium olivate is derived from olive oil that has been turned into soap.
An ingredient list that looks complicated at first glance may be describing a surprisingly simple bar of traditional soap.
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