Shampoo Bar? Hair Soap? What's the diff?

One can get down in the weedy-weeds with this question.  I certainly did!  But this post will take the well-groomed path and attempt to provide a succinct overview of these two choices that exist for those seeking waste-free, healthy hair care options.

First, Shampoo bars.  These little pucks have been growing in popularity for the past several years.  Basically, they are the cleansing ingredients in traditional shampoo bottles, without the added water or the bottle.  They are an excellent option for those interested in reducing waste and avoiding petroleum products.  They are sometimes referred to as "syn-det" bars, which is an abbreviation for exactly what they are primarily composed of, synthetic detergents.

Those of us who are interested in "natural" products and minimally processed ingredients may blanch at the ingredients list on a syn-det bar.  Let's take a look at the ingredients in a Mula Soap Shampoo Bar:

Sodium Cocoyl Isethionate, sodium lauryl sulfoacetate, cetyl alcohol, Cocamidopropyl betaine, behentrimonium methosulfate (and) ceteryl alcohol, jojoba oil, fragrance (phlatate free), argan oil, daikon seed oil, hydrolyzed oat protein, panthenol, Propylene Glycol, Diazolidinyl Urea, Iodopropynyl Butylcarbamate (preservative)

Now, if you have an aversion to ingredients with LOTS of syllables and you don't speak the language of "International Nomenclature of Cosmetic Ingredients," then that list is hella scary!  But a quick search of those ingredients will inform you of their benign intent and their usefulness in a gentle cleansing product like shampoo.  The reason these cleansing and moisturizing ingredients (surfactants and humectants in trade speak) are used in modern shampoo is that somewhere in history, we discovered that when combined carefully, they create a formula that matches the slightly acidic natural pH of the hair and scalp.  This means the structure of our hair, the follicle and scales of the strand, don't react to the pH of the product.  The hair and scalp can receive the cleansing or strengthening benefits of the formula without adjustment.  For many, this is a positive and healthy result, especially if one color treats their hair.

Soap differs from Shampoo Bars in that soap is made from oils, butters, liquid, and lye.  Many people with sensitive skin or allergies to synthetic surfactants find relief when they switch to soap.  In addition, the ingredients list of soap can feel wholesome and reassuring.  Let's look at the ingredients in a Mula Hair Soap:

*Coconut oil, Nettle-infused olive oil, water, *mango butter, sodium hydroxide, *sunflower oil, *avocado oil, jojoba oil, *castor oil, *flax seed gel, *hemp seed oil, sodium lactate, aloe powder, essential oil blend   (*organic)

Sounds pretty awesome right?  Why wouldn't you choose this for your hair over all those scary multi-syllabic ingredients?  Well, soap doesn't always play nice with everyone's hair, even an incredible soap like the one above.  Many people find their hair becomes lank and dull when they use soap to clean it.  Some of that result may be from the formulation of the soap itself but there is another culprit at play.

Our hair has a pH between 4.5-5. Soap is, by nature, an alkaline product with a pH of at least 8, and it will lift the scales of our hair initially, causing a “velcro-effect” whereby the strands stick to each other and appear limp.  The hair is clean, but appears lifeless and dull because of that reaction. However, a simple after-rinse with a weak vinegar solution usually rebalances the hair’s natural pH, allowing the scales to lie flat once more, revealing the natural bounce and shine.

Hair soap is not recommended for color-treated hair because the scale-lifting effect will cause color to fade more quickly.  Highlighted hair may be safe as the process involves removing color from the hair strand and color will not be further leached.

In conclusion, both Hair Soap and Shampoo Bars are economic, environmentally sound, and healthy ways to clean your hair and scalp, and both can be used all over the body!  There are many passionate testimonies on the superiority of one over the other, and it comes down to what your hair and scalp respond to and what you are drawn to.  

I hope this information helps you chose the product you are most curious about and that you have incredible illustrious results!