Exactly What Is Soap Made Of?

Exactly What Is Soap Made Of?

Have you ever wondered what soap is actually made out of? What makes soap… soapy? Since childhood, most of us have been encouraged (if not nagged) to use soap when washing our hands and body, without really being told what it actually is.

Do we really need soap and is there some special ingredient that makes it any different than if we were to just use a nice smelling oil? Does it actually kill germs or just wash them away? Let’s discuss!

First, let’s talk about what a soap “recipe” calls for and the ways that it can be made.

Soap is a combination of oils, fats, lye, and water (other ingredients can also be added for additional purposes such as color, fragrance, texture, and shelf life). These things get mixed together and must be combined in the proper proportions in order to chemically transform into soap through a process called saponification—that's right, there is an actual name for the process of becoming soap! 

Bubbly Belle has the scoop on all the sudsy details, so let’s dive in. 


Saponification is the name of the chemical process in which oils and fats react with lye or an alkali. Lye refers to any alkali, which is a water-soluble salt like sodium hydroxide or potassium hydroxide. The type of lye used will determine the type and form of the soap created.

When the alkali being used is sodium hydroxide, it creates a “hard” sodium soap. An alkali, like sodium hydroxide, is what helps form that beautiful soap bar that is just oh-so-satisfying to grab and lather up in the shower! The alkali is what combines and transforms all of the oils and other ingredients into the final finished product—it’s what makes soap, soap! 

Another option is to use potassium hydroxide as the lye or alkali in the recipe. If a potassium alkali is used instead of sodium, it will produce a "soft" soap in a liquid or cream form. If a soap lacks these natural ingredients and instead has a chemical replacement for the lye, then the final product is actually considered a detergent. 

Fats and Oils

Since fats and oils are a main part of the saponification process, you’ll commonly find a long list of various oils and fats under the ingredients of soap. The oils and fats are key players and a very important element of how that soap is going to look and feel. The types of oils used by the soap maker are going to determine how well the soap moisturizes, smells, and acts on your skin. 

Another important reason why oils are so vital in any soap recipe is that they are the part that actually removes the germs off of your hands. Germs like to hang out and gather on the natural oils found on our hands and bodies. Since water doesn’t mix with oil, washing our hands with just water alone can’t sufficiently grab any of those nasty little germs. 

How They Work

When we wash our hands with soap, the oils in the product work in and mix with the oils of our hands, acting as a liaison between our hands and the water. Then, we wash everything away together down the drain. When you see soaps marketed as “antibacterial” this means that a sanitizing (and usually chemical) agent has been added to the product.

However, this is not a necessary requirement to be considered “soap.” It’s through the saponification process that soap becomes a product that can effectively grab and wash away those same germs. 

When shopping for a moisturizing and soothing soap, look for ones that use natural oils rich in vitamins, antioxidants, and other skin-loving ingredients. The types of oils used in your soap are usually what will play a big role in adding to that overall luxurious lathering experience that leaves our skin feeling clean and soft. Here are a few of our favorite oils and fats to have in our soaps. 

Almond Oil

Sweet almond oil makes an excellent addition to any soap for its antioxidants and omega-3 fatty acids. It aids in fighting off free radicals and it’s easily absorbed to help nourish your skin!

Coconut Oil

This popular ingredient is commonly found in soaps and lotions for its amazing moisturizing abilities. It is said to help reduce inflammation, help hold in moisture on the skin, and even aid in clearing blemishes with its antimicrobial properties.

Avocado Oil

High in vitamin E and potassium, avocado oil is a superstar in any cosmetic product. It is said to help strengthen collagen in the skin with its oleic acid properties which can have anti-aging benefits. We’ll take all the help we can get!

Castor Oil

You’ve probably seen castor oil listed in the ingredients of most soaps. This is because its properties are known to produce a foamy, creamy, and luxurious lather. It offers amazing moisturizing benefits and is easily absorbed, making it a powerhouse ingredient in forming any great soap!

Palm Oil

Palm oil is a popular choice in soap and shampoo products due to its Vitamin E content and antioxidant properties. It is also particularly good at removing dirt and oil from the skin while providing moisture, which prevents the soap from stripping important oils that occur naturally on our skin.

Mango or Shea Butter

You’ll typically see shea or mango butter listed in the ingredients of soaps as one of the fats. These are popular choices that are both packed with nutrients. The fatty acids create a luxurious texture and add amazing moisturizing abilities to the product. 

Essential Oils

Another great ingredient you can commonly find in soaps is essential oils like lavender or eucalyptus. These oils are famous for their calming effect and for smelling amazing. Essential oils are always a great choice that will take your lathering experience to the next level for sure!

Cold Process vs. Hot Process Soap

Handmade soap can be made in two different ways: cold process and hot process. The recipes for both processes are usually the same. The only difference is the way the finished product looks, which is a result of ingredients being added at different times in each respective process. 

Isopropyl Alcohol 99%

Isopropyl alcohol (also known as rubbing alcohol) is a common ingredient used for the process of making handmade, cold-process soap. Usually, it is sprayed in a thin layer to help prevent soda ash and residue from forming in the saponification process. This helps the finished soap bar have a smooth, beautiful finish that feels better in your hand!

Sodium Lactate

When creating a product like soap, preservatives and thickening agents are typically necessary to help give a nice texture and also to keep any bacteria from growing on the product itself (especially in a damp environment like a shower—yikes!). 

Sodium lactate is a natural ingredient that helps preserve the soap and is a much safer option than the parabens you may find in some other products. Parabens are preservatives found in cosmetics and soaps that often have hormone-mimicking properties. Whenever possible, we recommend opting for natural, vegan, sustainably sourced soaps that don’t harm the environment with their production the way that some chemical manufacturing processes can.


Yes, water is needed to make soap! Water plays an important role in initiating the saponification process. The water on the ingredients list helps dissolve the lye so that it can interact with the oils and chemically combine together. Try and support companies that are conscious of their water usage in their manufacturing process, like Bubbly Belle. 

Additives? No thanks.

Harmful additives, parabens, and other synthetic chemicals (with names that are too hard to pronounce) can sometimes be added to soaps in order to make them look a certain way or last a certain amount of time on the shelf. We’ll pass on these potentially irritating products and opt for vegan, handmade products with better-for-you ingredients.


It’s nice to know that there actually was a reason that our parents were always bugging us to use soap when washing our hands as a kid! It turns out that they did know what they were talking about after all. 

Soap is the product you get after oils and fats have combined with an alkali (or soluble salt) through the saponification process. Then the soap, in all its sudsy goodness, is able to find and grab the germs off of our hands and bodies—in a way that water alone can’t do. Then we can wash germs and dirt away and down the drain for good. 

Who knew there were so many ingredients used and ways to make soap? The different varieties of ingredients you can find in soaps, like the examples listed above, are what can determine how moisturizing, soothing, and beneficial to the skin the final product will be. So be sure to choose one that will leave your skin feeling luxurious, silky, and can offer your skin the nourishment it needs.


Information about Soaps and Detergents | Healthy Cleaning 101 

Saponification | Chem Libretexts 

Sodium Hydroxide | Uses, Benefits, and Chemical Safety Facts | Chemical SafetyFacts

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