True Soap vs Synthetic Detergent Bars

You may be asking yourself what the difference is between a bar you buy from a soap-maker like myself, and a bar that you can pick up at your local grocery store. On the market currently, there are two main types of bars you can easily find for sale: True Soap and Syndet (Synthetic Detergent bars). Knowing your skin needs and your personal buying preferences can help you narrow this choice down, and no, all “soap” is not created equal.

True Soap

In order to be considered a ‘true soap’, a bar must meet the following criteria:

  • The bar must be made with a base or mixture of various oils and butters aka fatty acids.
  • The cleansing agent must be created through a saponification process using a chemical such as sodium hydroxide (lye) or potassium hydroxide aka alkali salts.
  • The bar may not include the addition of any synthetic detergents.
  • The bar may not make any additional claims beyond cleansing (there are some laws that allow claims based on commonly known and accepted uses, but that’s a whole other blog post).
  • The bar may not make any claims of disinfection or medicinal use otherwise it would fall under the FDA drug guidelines.

True soaps can be made small-batch and handmade, or on a large scale using standard manufacturing processes. In the United States, makers of true soap function under laws governing traditional products. We are allowed to create soap without the typical cosmetic testing and guidelines as long as it falls under the rules listed above.

True soap has many benefits: it makes use of an age-old, traditional process, some people find that their skin likes true soap more, and it supports a local business. Others just like being able to understand exactly what is going into the making of their skin care.

Synthetic Detergents (Syndet Bars)

Now, I’m not here to bash on synthetic detergents. They are an amazing part of our modern life and have their uses. They can include everything from the softest and most natural cleansing agents to surfactents like SLS and more. Often, these are the only bars some skin types can use. Syndet bars aren’t scary or bad, but it’s good to understand how they cleanse. It’s also good to understand that many of them may have additives that may make some skin issues worse.

You will never see these bars labeled with the word SOAP. Makers of syndet bars are required by the FDA to label their bars as “cleansing bars” or “face bar” or something similar. They are not allowed to use the word soap on their label. These bars are considered a cosmetic or a drug and fall under FDA purview.

Additional Learning

If you’re interested in this topic and want to learn more, one of my favorite websites recently posted a long-form video essay on this subject and about how to read soap labels: Reviewing Store-Bought Soap Labels.


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