The Difference Between Bar Soap and Shampoo Bars

The Difference Between Bar Soap and Shampoo Bars

One of the most asked question I get at our local Farmers markets is if our handmade soaps can be used on hair. While I guess “technically” they can be used to wash hair, they really are not formulated for hair. So, today we are going to go over the difference between bar soap and shampoo bars and how to tell the difference.

What is Bar Soap?


– Fatty Acids: Derived from animal fats (tallow) or plant oils (coconut, olive, palm).

– Alkali: Usually sodium hydroxide (lye) for the saponification process.

– Additives: Fragrances, colorants, and moisturizers like glycerin.


Bar soap is primarily designed for cleaning the skin. Its formulation focuses on removing dirt, oils, and bacteria from the skin’s surface.

 What is a Shampoo Bar?


– Surfactants: Often derived from coconut or palm oil, such as sodium coco sulfate, to create lather and clean the hair.

– Conditioners: Ingredients like shea butter, cocoa butter, or panthenol to nourish and moisturize the hair.

– Additives: Essential oils, herbal extracts, and proteins to enhance hair health and fragrance.


Shampoo bars are specifically formulated for hair care. They cleanse the scalp and hair, removing excess oils, dirt, and product buildup while providing conditioning benefits.

 Key Differences Between Bar Soap and Shampoo Bars

 pH Levels

– Bar Soap: Typically has a higher pH (9-10), which can be harsh and drying on the hair and scalp.

– Shampoo Bars: Formulated with a lower pH (4.5-6) to match the natural pH of the scalp and hair, maintaining balance and preventing dryness.

 Ingredients and Effects

– Bar Soap: The fatty acids and alkali in bar soap can strip the natural oils from hair, leading to dryness, frizz, and potential damage.

– Shampoo Bars: Surfactants and conditioners in shampoo bars are designed to gently cleanse without stripping natural oils, leaving hair soft, manageable, and healthy.


– Bar Soap: Best for skin cleansing, not suitable for hair due to its harsh formulation.

– Shampoo Bars: Specifically crafted for hair care, offering a balance of cleansing and conditioning.

How To Tell The Difference

The easies way to tell the difference between a soap bar and a shampoo bar is the ingredients. If a label has the ingredient lye, sodium hydroxide, potassium hydroxide, or says saponified oils of…. It is soap.

Understanding the difference between bar soap and shampoo bars is crucial for choosing the right product for your hair care routine. While bar soap is excellent for skin cleansing, it is not suitable for hair due to its high pH and harsh ingredients. Shampoo bars, on the other hand, are specifically designed to cleanse and condition hair, making them a better choice for maintaining healthy locks. When selecting a shampoo bar, consider your hair type and any specific needs to find the perfect match. Embrace the benefits of solid personal care products and enjoy the journey to healthier hair and a greener lifestyle.