Dianne's Blog

Shampoo Bars Vs Soap - Do you know the difference?
April 08, 2024

Shampoo Bars Vs Soap - Do you know the difference?

Welcome to my blog! I've been meaning to start one for a long time and there never seems to be enough hours in the day. I had intended to make my first blog post about soap ingredients, but nearly every day I see more companies touting their "shampoo" bars that really aren't and it annoys me. So, what better topic to start! 

First, the words soap and shampoo CANNOT be used interchangeably. They are two completely different compounds. It would be kind of like using the words water and vodka to mean the same clear liquid. 

Note: If you want to skip the chemistry and learn how a consumer can easily tell the difference, scroll to the end. 

Why would companies/makers market soap as shampoo? In my opinion, it comes down to two or three plausible explanations. First, the company is ignorant of the chemistry of soapmaking. Second, the company is preying on the ignorance of the consumer to sell product. Three, well maybe there are only two. 

Soap by definition is the compound that is created by the combination of fats & oils, with an alkali (most commonly sodium hydroxide aka lye). Soap has a pH between 9-10, which means it is alkaline. You CANNOT change the pH of soap by adding different oils, luxury butters or "conditioning" additives.

Shampoo by definition is a compound created by the combination of surfactants & co-surfactants with a salt. Most shampoos have a pH between 5.5 - 6.5, which means it is acidic. 

Why does this matter? It matters because human hair is sensitive to pH changes and is naturally on the acidic side with a pH near 5.5. It is able to maintain it's  integrity when exposed to compounds in or around that range. Water is generally neutral (pH = 7), which means what you apply to your hair should be close to your hair's pH of 5.5 or even slightly more acidic (less than 5.5) in order to maintain the healthy structure of the hair and microbiome of your scalp. 

What happens when you use soap on your hair? Using an alkaline substance (soap) on your hair disrupts the pH balance causing irreversible damage to the structure of your hair over time and scalp irritation. You may notice your hair is unable to retain moisture because the cuticles along the hair shaft have been raised. Your hair may frizz as the core of the strand seeks moisture from the atmosphere. Hair will feel like straw due to increased friction between strands due to the raised cuticles.

Despite the negative consequences of using soap on your hair, many people still do it. I know I'm generalizing here, but men seem to be able to "get away" with using soap more easily. Their hair is generally shorter and cut more often so damaged hair is removed much more frequently. 

And, it's convenient to use an "all-in-one" bar for those trying to replace more harmful products from their skin and hair care routines. But, you wouldn't expect to use soap as deodorant, so it's wise to recognize your bodies different chemical needs. 

So what about companies who do understand the chemistry and still sell soap as shampoo? I've read many, many forums and comments by other soapmakers who give reasons such as "soap ingredients are less scary and seem natural", and "soap is WAY cheaper to produce". In my opinion, that is completely dishonest and deliberately mis-leading to consumers. Soap is not shampoo. Shampoo is not soap. It's just factually wrong.

How to tell the difference? 

  1. Price: Soap is much cheaper & easier to produce. The ingredients to make real shampoo are WAY more expensive than any oils/lye used to make soap. If you are looking at a 3.5 - 5.0 oz bar that is under $10, it is SOAP.
  2. Ingredients: If the list contains the words "saponified oils", "lye" or "sodium hydroxide", it is SOAP.  There are no exceptions to this rule.
  3. The mention of pH on the packaging: The words "pH balanced" or "soap-free" are good indications that it is in fact SHAMPOO.

If you want to make the switch to solid shampoo, I would encourage you to check out our shampoo and conditioner bars. I can promise you that they are in fact shampoo, that they are pH balanced for hair, and also include many other hair loving ingredients such as nettle leaf, marshmallow root, and panthenol (pro-vitamin B5). 

As always, I hope I've provided some insight and education. 




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